Aluminium Alloys - New Trends in Fabrication and Applications 978-953-51-0861-0, 978-953-307-244-9

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Edi“ed by Zaki Ahmad

ALUMINIUM ALLOYS NEW TRENDS IN FABRICATION AND APPLICATIONS

ALUMINIUM ALLOYS NEW TRENDS IN FABRICATION AND APPLICATIONS Edi“ed by Zaki Ahmad

Aluminium Alloys - New Trends in Fabrication and Applications h““p://dx.doi.org/10.5772/3354 Edi“ed by Zaki Ahmad Contributors Pedro Vilaça, Pa“iphan J”ijerm, Igor Al“enberger, Vaclav - Sklenicka, Jiri Dvorak, Pe“r Kral, Milan Svoboda, Marie Kvapilova, Wojciech Lib”ra, Ar“”r Rekas, Alfredo Flores, Mohamed Mazari, Mohamed Beng”ediab, Mokh“ar Zemri, Bena““o” Bo”cho”icha, Vic“or Songmene, J”les Ko”am, Imed Zaghbani, Nick Parson, Alexandre Mal“ais, Amir Farzaneh, Maysam Mohammadi, Zaki Ahmad, Nick Birbilis, M”min SAHIN, Cenk Misirli, Paola Leo, Marek Balazinski, Pa“rick Hendrick

Published by InTech Janeza Trdine 9, 51000 Rijeka, Croa“ia Copyright © 2012 InTech All chap“ers are Open Access dis“rib”“ed ”nder “he Crea“ive Commons A““rib”“ion 3.0 license, which allows ”sers “o download, copy and b”ild ”pon p”blished ar“icles even for commercial p”rposes, as long as “he a”“hor and p”blisher are properly credi“ed, which ens”res maxim”m dissemina“ion and a wider impac“ of o”r p”blica“ions. Af“er “his work has been p”blished by InTech, a”“hors have “he righ“ “o rep”blish i“, in whole or par“, in any p”blica“ion of which “hey are “he a”“hor, and “o make o“her personal ”se of “he work. Any rep”blica“ion, referencing or personal ”se of “he work m”s“ explici“ly iden“ify “he original so”rce.

Notice S“a“emen“s and opinions expressed in “he chap“ers are “hese of “he individ”al con“rib”“ors and no“ necessarily “hose of “he edi“ors or p”blisher. No responsibili“y is accep“ed for “he acc”racy of informa“ion con“ained in “he p”blished chap“ers. The p”blisher ass”mes no responsibili“y for any damage or inj”ry “o persons or proper“y arising o”“ of “he ”se of any ma“erials, ins“r”c“ions, me“hods or ideas con“ained in “he book.

Publishing Process Manager Iva Simcic Technical Editor InTech DTP “eam Cover InTech Design “eam Firs“ p”blished December, 2012 Prin“ed in Croa“ia A free online edi“ion of “his book is available a“ www.in“echopen.com Addi“ional hard copies can be ob“ained from orders@in“echopen.com

Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions, Edi“ed by Zaki Ahmad p. cm. ISBN 978-953-51-0861-0

Con“en“s

Preface VII Section 1

Properties and Structure of Aluminium Alloys

1

Chap“er 1

Equal-Channel Angular Pressing and Creep in Ultrafine-Grained Aluminium and Its Alloys 3 Vaclav Sklenicka, Jiri Dvorak, Milan Svoboda, Pe“r Kral and Marie Kvapilova

Chap“er 2

Durability and Corrosion of Aluminium and Its Alloys: Overview, Property Space, Techniques and Developments 3 N. L. S”kiman, X. Zho”, N. Birbilis, A.E. H”ghes, J. M. C. Mol, S. J. Garcia, X. Zho” and G. E. Thompson

Chap“er 3

Influence of Structural Parameters on the Resistance on the Crack of Aluminium Alloy 47 Mohamed Mazari, Mohamed Beng”ediab, Mokh“ar Zemri and Bena““o” Bo”cho”icha

Chap“er 4

Effect of Micro Arc Oxidation Coatings on the Properties of Aluminium Alloys 99 Cenk Mısırlı, Mümin Şahin and Uf”k Sözer

Section 2

Extrusion, Rolling and Machining

Chap“er 5

Effects of Deep Rolling and Its Modification on Fatigue Performance of Aluminium Alloy AA6110 107 Pa“iphan J”ijerm and Igor Al“enberger

Chap“er 6

Numerical Modelling in Designing Aluminium Extrusion 123 Wojciech Lib”ra and Ar“”r Rękas

121

VI

Con“en“s

Chap“er 7

Linear Friction Based Processing Technologies for Aluminum Alloys: Surfacing, Stir Welding and Stir Channeling 137 Pedro Vilaça, João Gandra and Ca“arina Vidal

Chap“er 8

Dry, Semi-Dry and Wet Machining of 6061-T6 Aluminium Alloy 159 J. Ko”am, V. Songmene, M. Balazinski and P. Hendrick

Chap“er 9

Global Machinability of Al-Mg-Si Extrusions 199 V. Songmene, J. Ko”am, I. Zaghbani, N. Parson and A. Mal“ais

Section 3

Heat Treatment and Welding

Chap“er 10

Section 4

253

Pure 7000 Alloys: Microstructure, Heat Treatments and Hot Working 223 P. Leo and E. Cerri Durability, Degradation and Recycling of Aluminium Alloys 275

Chap“er 11

Mechanical and Metalurgical Properties of Friction Welded Aluminium Joints 255 M”min Sahin and Cenk Misirli

Chap“er 12

Elaboration of Al-Mn Alloys by Aluminothermic Reduction of Mn2O3 277 A. Flores Valdés , J. Torres and R. Ochoa Palacios

Section 5 Chap“er 13

Application of Aluminium Alloys in Solar Power

323

Aluminium Alloys in Solar Power − Benefits and Limitations 301 Amir Farzaneh, Maysam Mohammdi, Zaki Ahmad and In“esar Ahmad

Preface “ρumiσum aρρτys arκ στt τσρy sκrviσμ aκrτspaθκ, autτmτtivκ aσd rκσκwaηρκ κσκrμy iσdus‐ try thκy arκ ηκiσμ κxtκσsivκρy usκd iσ surλaθκ mτdiλiθatiτσ prτθκssκs at σaστsθaρκ suθh as mτdiλiκd phτsphτriθ aθid aστdiziσμ prτθκss tτ θrκatκ hiμh surλaθκ aθtivity τλ σaστpartiθρκs. ”κσiμσ οτiσiσμ τλ uρtra-λiσκ μraiσκd aκrτspaθκ aρumiσum aρρτys usiσμ σaστtκθhστρτμy is hiμhρy prτmisiσμ. Supκr hydrτphτηiθ surλaθκs havκ ηκκσ θrκatκd at a σaστsθaρκ tτ maπκ thκ surλaθκs dust aσd watκr rκpκρρκσt. Thκ ηiμμκst θhaρρκσμκ ρiκs iσ prτduθiσμ σaστstruθturκ mκtaρs at θτmpκtitivκ θτsts. Sκvκrκ pρastiθ dκλτrmatiτσ SPD is ηκiσμ dκvκρτpκd tτ prτduθκ στσmatκriaρ λτr spaθκ appρiθatiτσs. Thκ λτθus τλ sθiκσtists τσ usiσμ aρumiσum aρρτys λτr di‐ rκθt μκσκratiτσ τλ hydrτμκσ is rapidρy iσθrκasiσμ aσd dramatiθ prτμrκss has ηκκσ madκ iσ λaηriθatiτσ τλ “ρumiσum, Gaρρium aσd Θσdium aρρτys. Θt θaσ thκrκλτrκ sκκσ that thκ impτr‐ taσθκ τλ aρumiσum has σκvκr dκθρiσκd aσd it θτσtiσuκs tτ ηκ matκriaρ whiθh has attraθtκd thκ attκσtiτσ τλ sθiκσtists aσd κσμiσκκrs iσ aρρ κmκrμiσμ tκθhστρτμiκs. Θσ thκ θτσtκxt τλ thκ aητvκ θτmmκσts, thκrκ is ampρκ οustiλiθatiτσ λτr puηρishiσμ this ηττπ. Thκ θhaptκr ηy Prτλ. Sahiσ Mumiσ dκsθriηκs sτmκ τλ thκ impτrtaσt λuσdamκσtaρ prτpκrtiκs rκρatκd tτ mκtaρρurμiθaρ prτpκrtiκs aσd wκρdiσμ. Thκ prτθκdurκ aσd struθturaρ dκtaiρs τλ λriθ‐ tiτσ stir wκρdiσμ aσd λriθtiτσ stir θhaσσκρiσμ has ηκκσ dκmτσstratκd ηy Dr. Viρaça Pκdrτ with ηκautiλuρ iρρustratiτσs, dκκp rτρρiσμ aμκiσμ aσd aσd λatiμuκ θτσtrτρ thκ surλaθκ prτpκr‐ tiκs τλ aumiσium aρρτys. Dr.Θσμ. Ιuiοκrm Pathipham, has dκsθriηκd thκ impaθt τλ thκ aητvκ λaθtτrs θτmprκhκσsivκρy. Prτλ. Sπρκσiθπa Vadτv has dκsθriηκd thκ κquaρ θhaσσκρ aσμuρar prκssiσμ iσ rκρatiτσ tτ prτduθiσμ uρtra λivκ μraiσs matκriaρs with prτλusκ iρρustratiτσs aσd μraphiθs. Thκ rκadκrs iσtκrκstκd iσ σumκriθaρ mτdκρiσμ wτuρd λiσd thκ θhaptκr τσ σumκri‐ θaρ mτdκρiσμ vκry prτduθtivκ. Chaptκr τσ maθhaσaηiρity ηy Prτλ. Sτσμmκσκ Viθtτr λτθusκs τσ aumiσum, maμσκsiuσ aσd siρiθτσ aρρτys. Thκ κλλκθt τλ miθrτ arθ τxidatiτσ θτatiσμ τσ struθturκ aσd mκθhaσiθaρ paramκtκrs has ηκκσ shτwσ ηy Prτλ. Sahiσ Mumiσ. “ρumiσum is ηκiσμ iσθrκasiσμρy usκd iσ sτρar pτwκr duκ tτ its attriηutκs aσd it is κxtκσsivκρy usκd iσ θτσ‐ θκσtratiσμ sτρar pτwκr CSP aσd phτtτvτρtaρiθ sτρar θκρρs PV . Thκ rκadκr iσtκrκstκd iσ rκ‐ σκwaηρκ κσκrμy wτuρd λiσd thκ θhaptκr τσ aρumiσum aρρτys iσ sτρar pτwκr hiμhρy iσtκrκst‐ iσμ. Thκ sκθtiτσ τλ θτrrτsiτσ τλ PV mτduρκs has ηκκσ writtκσ θτmprκhκσsivκρy iσ this θhap‐ tκr. Θt is a μττd κxampρκ τλ iσtκrσatiτσaρ θτρρaητratiτσ as shτwσ ηy thκ authτrs λrτm Θraσ, Caσada, Paπistaσ aσd Saudi “raηia. ΘσTκθh is tτ ηκ θτσμratuρatκd λτr ηriσμiσμ a ηττπ τσ “ρumiσum aρρτys with σκw dimκσsiτσs prτρiλκratiσμ iσ vκσuκs τλ κmκrμiσμ tκθhστρτμiκs. Θ hτpκ studκσts at μraduatκ ρκvκρ aσd aρρ thκ rκsκarθhκrs wτuρd λiσd this ηττπ τλ μrκat iσtκrκst aσd sκvκrκ tτpiθ wτuρd stimuρatκ thκm iσ uσdκrtaπiσμ λurthκr rκsκarθh iσ arκas τλ iσtκrκst.

VIII

Preface

Thκ spirit τλ my dκθκasκd λathκr Waρi “hmκd aσd ρτviσμ mτthκr Ιamκκρa ”κμum aσd my dκθκasκd sτσ Θσtκπhaη “hmκd has mτtivatκd mκ iσ aρρ my aθadκmiθ θτσtriηutiτσs iσθρudiσμ this ηττπ. Θ thaσπ Shamsuοοκhaσ, Huma ”κμum, “ηida ”κμum, Farhat Suρtaσa λτr thκir κσ‐ θτuraμκmκσt. Θ thaσπ my μraσdsτσ Mr. Mishaaρ “hmκd λτr his hκρp. Θ thaσπ thκ dirκθtτr τλ COMS“TS Dr. M ”τdρa, Dr. Taρat “λza , Hκad τλ “θadκmiθs aσd Rκsκarθh COMS“TS aσd Dr. “ssaduρρah Khaσ, Hκad τλ Chκmiθaρ Dκpartmκσt λτr κσθτuraμκmκσt. Θ thaσπ Kiσμ Fahd Uσivκrsity τλ Pκtrτρκum aσd Miσκraρs, Dhahraσ, Saudi “raηia λτr prτvidiσμ mκ vκry prτ‐ duθtivκ wτrπiσμ yκars aσd κσvirτσmκσt. Θ thaσπ Miss Zahra Khaσ aσd Miss Tayyκηa τλ Chκm. Eσμ Dκpt. Θ thaσπ Dr Θσtκsar “hmκd τλ Lahτrκ Cτρρκμκ λτr Wτmκσ Uσivκrsity aσd Mr. Maσzar “hmκd τλ Uσivκrsity τλ Sτuth “sia λτr thκir hκρp. Fiσaρρy, Θ thaσπ “ρρah “ρ‐ miμhty λτr his θτuσtρκss ηρκssiσμs. Prof. Zaki Ahmad Uσivκrsity Fκρρτw aσd Fuρρ Prτλκssτr Dκpartmκσt τλ Maσuλaθturiσμ Eσμiσκκriσμ aσd Maσaμκmκσt Dκ La Saρρκ Uσivκrsity Phiρippiσκs

Section 1

Properties and Structure of Aluminium Alloys

Chapter 1

Equal-Channel Angular Pressing and Creep in UltrafineGrained Aluminium and Its Alloys Vaclav Sklenicka, Jiri Dvorak, Milan Svoboda, Pe“r Kral and Marie Kvapilova Addi“ional informa“ion is available a“ “he end of “he chap“er h““p://dx.doi.org/10.5772/51242

. Introduction Crκκp strκσμth aσd duθtiρity arκ thκ πκy θrκκp prτpκrtiκs τλ θrκκp-rκsistaσt matκriaρs ηut thκsκ prτpκrtiκs typiθaρρy havκ τppτsiσμ θharaθtκristiθs. Thus, matκriaρs with θτσvκσtiτσaρ μraiσ sizκs may ηκ strτσμ τr duθtiρκ ηut thκrκ arκ rarκρy ητth. Θσ this θτσσκθtiτσ, rκθκσt λiσdiσμs τλ hiμh strκσμth aσd μττd duθtiρity iσ sκvκraρ suηmiθrτmκtκr mκtaρs aσd aρρτys arκ τλ spκθiaρ iσ‐ tκrκst [ ]. Rκduθtiτσ τλ thκ μraiσ sizκ τλ a pτρyθrystaρρiσκ matκriaρ θaσ ηκ suθθκssλuρρy prτduθκd thrτuμh advaσθκd syσthκsis prτθκssκs suθh as thκ κρκθtrτdκpτsitiτσ tκθhσiquκ [ ] aσd sκvκrκ pρastiθ dκλτrmatiτσ SPD [ , - ]. “ρthτuμh θrκκp is aσ κxθκptiτσaρρy τρd arκa τλ rκsκarθh, aητvκ mκσtiτσκd prτθκssiσμ tκθhσiquκs havκ ηκθτmκ avaiρaηρκ τvκr thκ ρast twτ dκθadκs whiθh prτ‐ vidκ aσ τppτrtuσity tτ κxpaσd thκ θrκκp ηκhaviτur iσtτ σκw arκas that wκrκ στt λκasiηρκ iσ κar‐ ρiκr κxpκrimκσts. Crκκp tκstiσμ τλ σaστθrystaρρiσκ μraiσ sizκ d < σm aσd uρtraλiσκ-μraiσκd d< m matκriaρs is θharaθtκrizκd ηy λκaturκs that may ηκ diλλκrκσt λrτm thτsκ dτθumκσtκd λτr θτarsκ-μraiσκd matκriaρs aσd thus θaσστt κasiρy ηκ θτmparκd. Prτθκssiσμ thrτuμh thκ appρiθatiτσ τλ sκvκrκ pρastiθ dκλτrmatiτσ SPD is στw aσ aθθκptκd prτθκdurκ λτr prτduθiσμ ηuρπ uρtraλiσκ-μraiσκd matκriaρs haviσμ μraiσ sizκs iσ thκ suηmi‐ θrτmκtκr τr σaστmκtκr raσμκ. Thκ usκ τλ SPD κσhaσθκs θκrtaiσ matκriaρ prτpκrtiκs thrτuμh thκ iσtrτduθtiτσ τλ aσ uρtraλiσκ-μraiσκd miθrτstruθturκ. Thκ uρtraλiσκ sizκ τλ thκ μraiσs iσ thκ ηuρπ matκriaρs μκσκraρρy ρκads tτ siμσiλiθaσtρy imprτvκd prτpκrtiκs ηy θτmparisτσ with pτρyθrys‐ taρρiσκ matκriaρs haviσμ θτσvκσtiτσaρ μraiσ sizκs τλ thκ samκ θhκmiθaρ θτmpτsitiτσ. Sκvκraρ SPD prτθκssiσμ tκθhσiquκs arκ θurrκσtρy avaiρaηρκ ηut thκ mτst attraθtivκ tκθhσiquκ is κquaρθhaσσκρ aσμuρar prκssiσμ EC“P , whκrκ thκ sampρκ is prκssκd thrτuμh a diκ θτσstraiσκd with‐ iσ a θhaσσκρ ηκσt thrτuμh aσ aηrupt aσμρκ [ ]. Thκrκ arκ σumκrτus rκpτrts τλ thκ prτθκssiσμ τλ variτus purκ mκtaρs aσd mκtaρρiθ aρρτys ηy EC“P aσd maσy τλ thκsκ rκpτrts iσvτρvκ a θharaθ‐

4

Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

tκrizatiτσ τλ thκ miθrτstruθturκ aσd aσ iσvκstiμatiτσ τλ thκ mκθhaσiθaρ prτpκrtiκs at amηiκσt tκmpκraturκs. Thκrκ arκ aρsτ sκvκraρ rκpτrts τλ thκ tκσsiρκ prτpκrtiκs τλ thκ as-prκssκd matκri‐ aρs at κρκvatκd tκmpκraturκs with a spκθiaρ κmphasis τσ thκ pτtκσtiaρ λτr aθhiκviσμ hiμh supκr‐ pρastiθ κρτσμatiτσs. Hτwκvκr, thκ tκsts at κρκvatκd tκmpκraturκs arκ iσvariaηρy θτσduθtκd uσdκr θτσditiτσs τλ θτσstaσt straiσ ratκ aσd, ηy θτσtrast, τσρy vκry ρimitκd rκpτrts arκ avaiρa‐ ηρκ dκsθriηiσμ thκ θrκκp ηκhaviτur τλ aρumiσium aσd sτmκ aρumiσium aρρτys. Furthκrmτrκ, thκ rκsuρts λτr hiμh-purity aρumiσium, whiθh arκ thκ mτst κxtκσsivκ avaiρaηρκ tτ datκ, appκar aστmaρτus ηκθausκ uσdκr sτmκ tκstiσμ θτσditiτσs τλ strκss aσd tκmpκraturκ thκ mκasurκd miσimum τr stκady-statκ θrκκp ratκs iσ thκ prκssκd matκriaρs with uρtraλiσκ μraiσ sizκs whκrκ sρτwκr thaσ iσ thκ samκ matκriaρ iσ a θτarsκ-μraiσκd uσprκssκd θτσditiτσ. This θhaptκr was iσitiatκd tτ prτvidκ ηasiθ iσλτrmatiτσ τσ thκ θrκκp ηκhaviτur aσd miθrτ‐ struθturaρ θharaθtκristiθs τλ aρumiσium aσd sτmκ aρumiσium aρρτys. Thκ θhaptκr has aris‐ κσ iσ θτσσκθtiτσ with ρτσμ-tκrm rκsκarθh aθtivity τλ thκ “dvaσθκd Hiμh Tκmpκraturκ Matκriaρs Grτup at thκ Θσstitutκ τλ Physiθs τλ Matκriaρs, “θadκmy τλ Sθiκσθκs τλ thκ Czκθh Rκpuηρiθ iσ ”rστ, Czκθh Rκpuηρiθ. Thus, thκ τηοκθtivκ τλ this θhaptκr is tτ prκsκσt aσ τvκrviκw τλ sτmκ rκsuρts τλ τur θurrκσt rκsκarθh iσ θrκκp ηκhaviτur aσd a ρiσπ ηκtwκκσ thκ miθrτstruθturκ aσd thκ θrκκp prτpκrtiκs τλ uρtraλiσκ-μraiσκd aρumiσium ηasκd aρρτys. Thrτuμhτut thκ tκxt, τur rκsuρts arκ θτmparκd with thκτrκtiθaρ mτdκρs aσd rκρκvaσt κx‐ pκrimκσtaρ τηsκrvatiτσs puηρishκd iσ thκ ρitκraturκ.

. The development of processing using equal-channel angular pressing ECAP Prτθκssiσμ ηy sκvκrκ pρastiθ dκλτrmatiτσ SPD may ηκ dκλiσκd as thτsκ mκtaρ λτrmiσμ prτ‐ θκdurκs iσ whiθh a vκry hiμh straiσ is impτsκd τσ a ηuρπ sτρid withτut thκ iσtrτduθtiτσ τλ aσy siμσiλiθaσt θhaσμκ iσ thκ τvκraρρ dimκσsiτσs τλ thκ sτρid aσd ρκadiσμ tτ thκ prτduθtiτσ τλ κxθκptiτσaρ μraiσ rκλiσκmκσt tτ that thκ prτθκssκd ηuρπ sτρids havκ τr mτrκ μraiσs iσ sκθtiτσ [ ]. Oλ a widκ divκrsity τλ σκw SPD prτθκdurκs, κquaρ-θhaσσκρ aσμuρar prκssiσμ EC“P is aσ κspκθiaρρy attraθtivκ prτθκssiσμ tκθhσiquκ. Θt is rκρativκρy simpρκ prτθκdurκ whiθh θaσ ηκ appρiκd tτ λairρy ρarμκ ηiρρκts τλ maσy matκriaρs raσμiσμ λrτm purκ mκtaρs tτ prκθipitatiτσ-hardκσκd aρρτys, iσtκrmκtaρρiθs aσd mκtaρ-matrix θτmpτsitκs. . . Principles of ECAP Thκ priσθipρκ τλ EC“P is iρρustratκd sθhκmatiθaρρy iσ Fiμurκ . Fτr thκ diκ shτwσ iσ Fiμurκ , thκ iσtκrσaρ θhaσσκρ is ηκσt thrτuμh aσ aηrupt aσμρκ, Φ, aσd thκrκ is aσ additiτσaρ aσμρκ, , whiθh rκprκsκσts τutκr arθ τλ θurvaturκ whκrκ thκ twτ θhaσσκρs iσtκrsκθt. Thκ sampρκ, iσ thκ λτrm τλ a rτd τr ηar, is maθhiσκd tτ λit withiσ θhaσσκρ aσd thκ diκ is pρaθκd iσ sτmκ λτrm τλ λuss sτ that thκ sampρκ θaσ ηκ prκssκd thrτuμh thκ diκ usiσμ a pρuσμκr. Thκ σaturκ τλ thκ impτsκd dκλτrmatiτσ is simpρκ shκar whiθh τθθurs as thκ ηiρρκt passκs thrτuμh thκ diκ. Thκ rκtκσtiτσ τλ thκ samκ θrτss-sκθtiτσaρ arκa whκσ prτθκssiσμ ηy EC“P, dκspitκ thκ iσtrτduθ‐ tiτσ τλ vκry ρarμκ straiσs, is thκ impτrtaσt θharaθtκristiθ τλ SPD prτθκssiσμ aσd it is θharaθ‐

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

tκristiθ whiθh distiσμuishκs this typκ τλ prτθκssiσμ λrτm θτσvκσtiτσaρ mκtaρ-wτrπiσμ τpκratiτσs suθh as rτρρiσμ, κxtrusiτσ aσd drawiσμ. Siσθκ thκ θrτss-sκθtiτσaρ arκa rκmaiσs uσ‐ θhaσμκd, thκ samκ ηiρρκt may ηκ prκssκd rκpκtitivκρy tτ attaiσ κxθκptiτσaρρy hiμh straiσ.

Figure 1. Principle of ECAP.

“ρumiσium aσd its aρρτys usκd iσ this iσvκstiμatiτσ wκrκ prκssκd usiσμ aσ κxpκrimκσtaρ λa‐ θiρity λτr EC“P iσstaρρκd iσ thκ Θσstitutκ τλ Physiθs τλ Matκriaρs, “θadκmy τλ Sθiκσθκs τλ thκ Czκθh Rκpuηρiθ Fiμurκ . Thκ diκ was pρaθκd τσ a tκstiσμ maθhiσκ Zwiθπ. EC“P was θτσ‐ duθtκd mτstρy at rττm tκmpκraturκ with a diκ that had iσtκrσaρ aσμρκ ° ηκtwκκσ twτ parts τλ thκ θhaσσκρ aσd aσ τutκr arθ τλ θurvaturκ τλ ~ °, whκrκ thκsκ twτ parts iσtκrsκθt. Θt θaσ ηκ shτwσ λrτm λirst priσθipρκs that thκsκ aσμρκs ρκad tτ aσ impτsκd straiσ τλ ~ iσ κaθh pas‐ saμκ τλ thκ sampρκ. Thκ EC“P diκ iσvτρvκd thκ usκ τλ ηiρρκts τλ thκ ρκσμth τλ ~ ª mm with squarκ θrτss-sκθtiτσ τλ mm x mm. Thκ vκρτθity τλ pρuσμκr was mm/miσ. . . The processing routes in ECAP Thκ usκ τλ rκpκtitivκ prκssiσμ prτvidκs aσ τppτrtuσity tτ iσvτπκ diλλκrκσt sρip systκms τσ κaθh θτσsκθutivκ pass ηy simpρy rτtatiσμ thκ sampρκs iσ diλλκrκσt ways. Thκ λτur diλλκrκσt prτθκssiσμ rτutκs arκ summarizκd sθhκmatiθaρρy iσ Fiμurκ [ ]. Θσ rτutκ “ thκ sampρκ is prκssκd withτut rτtatiτσ, iσ rτutκ ”“ thκ sampρκ is rτtatκd ηy ° iσ aρtκrσatκ dirκθtiτσs ηκtwκκσ θτσsκθutivκ passκs, iσ rτutκ ”C thκ sampρκ is rτtatκd ηy ° iσ thκ samκ sκσsκ κi‐ thκr θρτθπwisκ τr θτuσtκr θρτθπwisκ ηκtwκκσ κaθh pass aσd iσ rτutκ C thκ sampρκ is rτ‐ tatκd ηy ° ηκtwκκσ passκs. Thκ distiσθtiτσ ηκtwκκσ thκsκ rτutκs aσd thκ diλλκrκσθκ iσ σumηκr τλ EC“P passκs may ρκad tτ variatiτσs ητth iσ thκ maθrτsθτpiθ distτrtiτσs τλ thκ iσdividuaρ μraiσs [ ] aσd iσ thκ θapaηiρity tτ dκvκρτp a rκasτσaηρy hτmτμκσκτus aσd κquiaxκd uρtraλiσκ-μraiσκd miθrτstruθturκ.

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Figure 2. Adap“a“ion of “es“ing ZWICK machine for ECAP pressing (a, b), and (c) ske“ch of ECAP die design.

Figure 3. Schema“ic of fo”r ECAP ro”“es for repe“i“ive pressing.

Θσ this wτrπ thκ EC“P prκssiσμ was θτσduθtκd iσ suθh a way that τσκ τr rκpκtitivκ prκssiσμ was θτσduθtκd λτρρτwκd κithκr rτutκ “, ” rτutκ ”C was usκd τσρy τr C. Dκtaiρκd κxamiσa‐ tiτσs τλ thκ κλλκθt τλ diλλκrκσt prτθκssiσμ rτutκs shτwκd that rτutκ ”C ρκads tτ thκ mτst rapid κvτρutiτσ iσtτ aσ array τλ hiμh-aσμρκ μraiσ ητuσdariκs [ , ]. Thκ rκsuρt is κxpρaiσκd ηy θτσ‐ sidκriσμ thκ shκariσμ pattκrσs dκvκρτpκd iσ thκ sampρκs duriσμ κaθh prτθκssiσμ rτutκ. Thus,

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

thκ rτutκ ”C is mτst prτηaηρy thκ τptimum EC“P prτθκssiσμ rτutκ at ρκast λτr thκ prκssiσμ τλ purκ aρumiσium aσd its aρρτys [ ]. . . Mechanical properties and defects achieved using ECAP Duriσμ thκ ρast twτ dκθadκs it has ηκκσ dκmτσstratκd that aσ uρtraλiσκ-μraiσκd struθturκ τλ matκriaρs prτθκssκd ηy EC“P may ρκad tτ siμσiλiθaσtρy hiμhκr strκσμth aσd hardσκss ηut tτ a rκduθtiτσ iσ thκ duθtiρity [ ]. Θσ this θτσσκθtiτσ aλtκr EC“P thκ mκθhaσiθaρ prτpκrtiκs wκrκ tκstκd mτstρy at rττm tκmpκraturκ usiσμ a tκstiσμ maθhiσκ τpκratiσμ at a θτσstaσt ratκ τλ . x - s- τλ θrτsshκad dispρaθκmκσt. . . . Tensile properties Tκσsiρκ tκsts wκrκ θτσduθtκd at K τσ purκ aρumiσium aλtκr prτθκssiσμ ηy EC“P λτr sam‐ pρκs aλtκr diλλκrκσt σumηκr τλ EC“P passκs. Θσ ρimitκd κxtκσt mκθhaσiθaρ tκsts wκrκ pκrλτrmκd τσ thκ sampρκs aλtκr EC“P aσd statiθ aσσκaρiσμ at K [ ]. Θσ Fiμurκ thκ tκσsiρκ data arκ summarizκd as a λuσθtiτσ τλ thκ σumηκr τλ passκs. Θt is apparκσt λrτm thκsκ λiμurκs that a vκry siμσiλiθaσt iσθrκasκ iσ yiκρd aσd uρtimatκ tκσsiρκ strκss τθθurrκd aλtκr thκ λirst prκssiσμ. Thκ suηsκquκσt prκssiσμ λurthκr iσθrκasκd yiκρd aσd uρtimatκ strκss vaρuκs ηut tτ a ρτwκr ratκ. Fur‐ thκr, a saturatiτσ τλ thκ ρκvκρ τλ ητth thκ paramκtκrs was attaiσκd aλtκr λτur passκs.

Figure 4. Infl”ence of differen“ ECAP ro”“es and differen“ n”mber of ECAP passes on (a) yield s“ress, and (b) ”l“ima“e “ensile s“ress af“er s“a“ic annealing.

Frτm Fiμurκ it θaσ ηκ aρsτ στtiθκd that statiθ aσσκaρiσμ at K ρκads tτ a suηstaσtiaρ dκ‐ θrκasκ iσ thκ ρκvκρ τλ yiκρd aσd uρtimatκ tκσsiρκ strκss vaρuκs duκ tτ diλλusiτσ ηasκd rκθτvκry prτθκssκs λτr aρρ thκ EC“P prτθκssκd sampρκs. Nτ siμσiλiθaσt diλλκrκσθκs iσ mκθhaσiθaρ prτpκrtiκs amτσμ thκ EC“P prτθκss rτutκs κxamiσκd wκrκ λτuσd. Furthκr, λrτm Fiμurκ is θρκar that aρthτuμh thκ ρκvκρs τλ thκ tκσsiρκ data λτr EC“Pκd “ρ hiμhρy dκθrκasκ with thκ σumηκr τλ EC“P passκs, thκ strκss ρκvκρs aλtκr passκs arκ muθh hiμhκr thaσ thκ strκss ρκv‐ κρs iσ thκ aσσκaρiσμ statκ aσd thκsκ diλλκrκσθκs θτmκ tτ mτrκ thaσ twiθκ. This rκsuρt iσdi‐

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θatκs that, whκσ θτmparκd with thκ tκσsiρκ ηκhaviτur τλ thκ aσσκaρκd statκ, thκ λρτw strκss is θτσsidκraηρy imprτvκd thrτuμh thκ appρiθatiτσ τλ EC“P [ , ]. . . . Hardness measurements Fiμurκ a shτws Viθπκrs miθrτhardσκss pρτttκd aμaiσst thκ σumηκr τλ EC“P passκs λτr κx‐ trκmκρy hiμh purity aρumiσium . % [ ]. Thκ hardσκss iσθrκasκs up tτ twτ passκs tτ taπκ a maximum duκ tτ thκ vκry hiμh disρτθatiτσ dκσsity. Hτwκvκr, suηsκquκσt passκs ρκad tτ a dκθrκasκ iσ thκ hardσκss ηκθausκ maσy τλ thκ suημraiσ ητuσdariκs κvτρvκ iσtτ hiμh-aσ‐ μρκ μraiσ ητuσdariκs. Fiμurκ η shτws Viθπκrs miθrτhardσκss pρτttκd aμaiσst diλλκrκσt pκri‐ τds τλ timκ τλ a statiθ aσσκaρiσμ at K λτr purκ . % “ρ prτθκssκd ηy EC“P ηy twτ diλλκrκσt prτθκssiσμ rτutκs. “ prτστuσθκd dκθrκasκ τλ miθrτhardσκss with aσ iσθrκasκ τλ aσσκaρiσμ timκ θaσ ηκ κxpρaiσκd ηy siμσiλiθaσt μraiσ μrτwth aσd sτλtκσiσμ τλ prκssκd matκ‐ riaρ duriσμ aσ aσσκaρiσμ κxpτsurκs [ ].

Figure 5. Hardness changes (a) wi“h respec“ “o n”mber of ECAP passes, and (b) as a f”nc“ion of annealing “ime a“ 473 K for “wo differen“ ECAP ro”“es.

. . . Nanoporosity after ECAP proθessing Θt is μκσκraρρy rκθτμσizκd that thκ EC“P prτθκss θτuρd prτduθκ a suηmiθrτθrystaρρiσκ ηuρπ matκriaρ with a rκρativκρy uσiλτrm struθturκ aσd % dκσsity λτr a widκ raσμκ τλ matκriaρs λrτm purκ mκtaρs, sτρid-sτρutiτσ aρρτys, θτmmκrθiaρ aρρτys, tτ mκtaρ matrix θτm‐ pτsitκs [ ]. Hτwκvκr, thκ prκviτusρy pκrλτrmκd aσaρysis τλ thκ data τσ thκ iσλρuκσθκ τλ thκ σumηκr τλ passκs τλ κquaρ-θhaσσκρ aσμuρar prκssiσμ τσ thκ κρastiθ-pρastiθ prτpκrtiκs aσd dκλκθt struθturκ τλ purκ aρumiσium dκmτσstratκd that thκsκ θharaθtκristiθs τλ mκ‐ θhaσiθaρ prτpκrtiκs arκ suηstaσtiaρρy aλλκθtκd ηy thκ κvτρutiτσ τλ thκ σaστpτrτsity λτrmκd duriσμ κquaρ-θhaσσκρ aσμuρar prκssiσμ [ - ]. Thus, tτ dκtκrmiσκ thκ tτtaρ vτρumκ τλ σaστpτrτsity whiθh θτuρd ηκ μκσκratκd ηy EC“P, twτ sκρκθtκd sampρκs τλ purκ aρumiσi‐ um wκrκ prκssκd λτr a tτtaρ τλ τσκ spκθimκσ “ aσd λτur spκθimκσ “ EC“P passκs,

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

rκspκθtivκρy, aσd λτr θτmparisτσ rκasτσs sτmκ part τλ thκsκ spκθimκσs wκrκ uσdκrwκσt ηy suηsκquκσt prκssurizatiτσ trκatmκσt ηy hiμh hydrτstatiθ prκssurκ [ ]. Thκ sampρκs wκrκ iσvκstiμatκd ηy smaρρ-aσμρκ Ψ-ray sθattκriσμ S“ΨS aσd diρatτmκtry [ ]. Sτmκ diλλκrκσθκs wκrκ λτuσd iσ thκ λraθtiτσaρ vτρumκ τλ thκ σaστpτrκs ΔV/V whκσ θτm‐ parκd spκθimκσ “ tτ spκθimκσ “ . Thκ vaρuκs ΔV/Vmax θτrrκspτσd tτ thκ as-prκssκd statκ τλ spκθimκσs aλtκr EC“P τσρy aσd thκ vaρuκs ΔV/Vmiσ wκrκ κvaρuatκd λτr thκ statκ aλtκr EC“P aσd suηsκquκσt prκssurizatiτσ whiθh rκprκsκσts a rκοuvκσativκ trκatmκσt λτr κρimiσa‐ tiτσ τλ σaστpτrκs. Thκ κvaρuatκd vaρuκs arκ ΔV/Vmax = x - aσd ΔV/Vmiσ = . . - λτr spκθi‐ mκσ “ aσd ΔV/Vmax = x - aσd ΔV/Vmiσ = x - λτr spκθimκσ “ , rκspκθtivκρy. Nτ suηstaσtiaρ diλλκrκσθκ iσ thκ avκraμκ sizκ τλ thκ σaστpτrκs ~ - σm was λτuσd ηκtwκκσ thκ spκθimκσs iσvκstiμatκd. Thκ vaρuκs ΔV/V dκtκrmiσκd ηy smaρρ-aσμρκ Ψ-ray sθattκriσμ aσd diρatτmκtry wκrκ aητut thκ samκ κ.μ. thκ λraθtiτσaρ vτρumκ ΔV/Vmiσ = x - ηy S“ΨS τλ spκθimκσ “ aμrκκd vκry wκρρ with ΔV/Vmiσ = . x - as dκtκrmiσκd ηy diρatτmκtry. Oσ thκ ηasis τλ thκ aλτrκmκσtiτσκd rκsuρts wκ θaσ θτσθρudκ that EC“P dκλτrmatiτσ aθhiκvκs strτσμρy κσhaσθκd θτσθκσtratiτσ τλ vaθaσθy aμμρτmκratκs typκ dκλκθts. Thκ κλλκθt τλ thκ spκθtrum τλ thκ pτiσt dκλκθts aσd thκ iσtκrσaρ strκssκs τσ κρastiθity aσd aσκρastiθity τλ EC“P‐ κd aρumiσium has ηκκσ rκpτrtκd κρsκwhκrκ [ ]. Θσ rκθκσt yκars usiσμ a ηaθπ-prκssurκ EC“P λaθiρitiκs [ ] has ηκθτmκ aσ arκa τλ spκθiaρ iσtκr‐ κst. “σ impτrtaσt advaσtaμκ iσ impτsiσμ a ηaθπ-prκssurκ may ηκ a dκθrκasκ τλ σaστpτrτsi‐ ty iσ thκ prκssκd matκriaρ [ ]. Hτwκvκr, additiτσaρ κxpκrimκσts arκ σκκdκd tτ κvaρuatκ thκ rτρκ τλ a ηaθπ-prκssurκ iσ κρimiσatiτσ τλ σaστpτrτsity.

. Microstructural features of ultrafine-grained materials Uρtraλiσκ-μraiσκd UFG matκriaρs prτθκssκd ηy EC“P diλλκr quaρitativκρy aσd quaσtita‐ tivκρy λrτm thκir θτarsκ-μraiσκd CG θτuσtκrparts iσ tκrms τλ thκir θharaθtκristiθ struθtur‐ aρ paramκtκrs aσd thus thκir θrκκp ηκhaviτur θaσστt ηκ κasiρy θτmparκd with that dτθumκσtκd λτr CG matκriaρs. Θt is impτrtaσt tτ στtκ iσ this rκspκθt that UFG matκriaρs arκ θharaθtκrizκd ηy μrκat κxtκσsiτσ τλ iσtκrσaρ iσtκrλaθκs thκrκλτrκ, μraiσ ητuσdary diλλu‐ siτσ prτθκssκs havκ tτ ηκ iσvτρvκd iσ thκ λτrmatiτσ τλ thκir struθturκ-sκσsitivκ prτpκrtiκs, κspκθiaρρy at κρκvatκd tκmpκraturκ [ ]. Thκ θharaθtκristiθs τλ thκ miθrτstruθturκs iσtrτduθκd ηy EC“P havκ ηκκσ κvaρuatκd iσ σu‐ mκrτus iσvκstiμatiτσs [ ]. Hτwκvκr, mτst τλ thκsκ κarρiκr iσvκstiμatiτσs κmpρτyκd traσsmis‐ siτσ κρκθtrτσ miθrτsθτpy TEM λτr dκtκrmiσatiτσs τλ thκ μraiσ sizκs prτduθκd ηy EC“P aσd thκ σaturκ τλ aσy disρτθatiτσ iσtκraθtiτσs τθθurriσμ withiσ μraiσs. Thκ appρiθatiτσ τλ mτdκrσ imaμiσμ mκthτds tτ thκ κxamiσatiτσ τλ miθrτstruθturκs iσ UFG matκriaρs prτθκssκd ηy EC“P has pκrmittκd a mτrκ dκtaiρκd iσvκstiμatiτσ τλ a pτssiηρκ ρiσπ ηκtwκκσ iσtκrσaρ mi‐ θrτstruθturκs τλ UFG mκtaρs aσd aρρτys aσd thκir mκθhaσiθaρ aσd/τr θrκκp ηκhaviτur [ ]. Diλλraθtiτσ-ηasκd tκθhσiquκs λτr ρτθaρizκd θrystaρ τriκσtatiτσ mκasurκmκσts, suθh as κρκθ‐ trτσ ηaθπsθattκr diλλraθtiτσ E”SD , arκ τλ θκσtraρ impτrtaσθκ tτday λτr θharaθtκriziσμ λiσκsθaρκ miθrτstruθturaρ λκaturκs [ - ].

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Thκ σκw κxpκrimκσtaρ tκθhσiquκ τλ E”SD θτσsidκraηρy κxtκσdκd thκ pτssiηiρitiκs τλ mκtaρ‐ ρτμraphy tτ κstimatκ rκρiaηρy thκ quaσtitativκ struθturaρ θharaθtκristiθs τλ matκriaρs [ ]. Θt κσaηρκs thκ σumκriθaρ θρassiλiθatiτσ τλ ητuσdariκs sκparatiσμ thκ rκμiτσs τλ diλλκrκσt τriκσta‐ tiτσs τλ thκir ρattiθκ struθturκ. Thκ maμσitudκ τλ thκ mutuaρ misτriκσtatiτσ θaσ ηκ θτσtiσu‐ τusρy sκρκθtκd aσd thus thκ rκμiτσs with a misτriκσtatiτσ ρκss thaσ a prκsθriηκd vaρuκ as wκρρ as thκir ητuσdariκs θaσ ηκ rκθτμσizκd. Thκrκ is a vast ρitκraturκ dκvτtκd tτ thκ τηsκrva‐ tiτσ ηy E”SD aσd prκθisκρy dκλiσκd misτriκσtatiτσ τλ ητuσdariκs aσd thκ θτσvκσtiτσaρ μraiσ ητuσdary θρassiλiθatiτσ ηasκd τσ suitaηρy pτρishκd aσd κtθhκd pρaσar surλaθκs as τηsκrvκd ηy τptiθaρ miθrτsθτpy τr ηy ητuσdariκs τηsκrvκd ηy κρκθtrτσ miθrτsθτpy aσd E”SD sκκ κ.μ. [ ] . “s θaσ ηκ κxpκθtκd, thκ E”SD mκthτd is mτrκ rκprτduθiηρκ, iσdκpκσdκσt τλ dκtaiρκd κtθhiσμ θτσditiτσs κtθ., aσd thκ surλaθκ arκa iσtκσsitiκs arκ usuaρρy hiμhκr κquivaρκσtρy, thκ mκaσ raσdτm prτλiρκ θhτrd is smaρρκr . Θσ this sκθtiτσ a divisiτσ τλ ητuσdariκs iσtτ truκ suη‐ ητuσdariκs with misτriκσtatiτσs Δ < °, traσsitiτσaρ suηητuσdariκs with ° Δ < °aσd hiμh-aσμρκ μraiσ ητuσdariκs with Δ ≥ ° was madκ. Suθh aσ apprτaθh is τλ primary impτrtaσθκ iσ thκ κxamiσatiτσ τλ matκriaρs prτduθκd ηy sκ‐ vκrκ pρastiθ dκλτrmatiτσ SPD , withτut θhaσμκ τλ shapκ, prτduθiσμ matκriaρs with uρtraλiσκ μraiσs κ.μ. [ , ] aσd θτσsidκraηρy diλλκrκσt prτpκrtiκs iσ θτmparisτσ with CG matκriaρs. Thκ rκasτσ λτr this diλλκrκσθκ is tτ a θκrtaiσ dκμrκκ purκρy μκτmκtriθ aσd θτσsists iσ diλλκr‐ κσt μraiσ aσd suημraiσ ητuσdary struθturκs, whiθh pρay aσ impτrtaσt rτρκ iσ mκθhaσiθaρ, thκrmaρ aσd τthκr prτpκrtiκs. This sκθtiτσ dκsθriηκs thκ rκsuρts τλ struθturaρ κxamiσatiτσs τλ hiμh purity aρumiσium aσd its sκρκθtκd prκθipitatiτσ-strκσμthκσκd aρρτys prτθκssκd ηy EC“P. Thκ miθrτstruθturκ was rκ‐ vκaρκd ηy TEM, SEM aσd E”SD aσd aσaρyzκd quaσtitativκρy ηy stκrκτρτμiθaρ mκthτds. Thκ variτus λaθtτrs iσλρuκσθiσμ thκ as-prκssκd miθrτstruθturκs iσθρudiσμ thκ tτtaρ straiσ impτsκd iσ EC“P prτθκssiσμ, thκ prτθκssiσμ rτutκs aσd thκ σaturκ τλ matκriaρs arκ κxamiσκd iσ dκtaiρ. . . Experimental materials and their microstructure after ECAP . . . Pure aluminium Thκ aρumiσium usκd iσ this iσvκstiμatiτσ was aσ κxtrκmκρy θτarsκ-μraiσκd μraiσ sizκ ~ mm hiμh purity . % “ρ suppρiκd iσ thκ λτrm τλ rτds. Thκ rτds wκrκ θut iσtτ shτrt ηiρρκts haviσμ a ρκσμth τλ ~ mm aσd a θrτss-sκθtiτσ mm x mm. EC“P was θτσ‐ duθtκd at rττm tκmpκraturκ usiσμ rτutκ “, ”C aσd C. Fuρρ dκtaiρs τσ thκ prτθκssiσμ havκ ηκκσ dκsθriηκd κρsκwhκrκ [ - ]. TEM rκsuρts havκ shτwσ that τσκ EC“P pass ρκads tτ a suηstaσtiaρ rκduθtiτσ iσ thκ μraiσ sizκ ~ . m , aσd thκ miθrτstruθturκ θτσsists τλ paraρρκρ ηaσds τλ μraiσs τriκσtκd iσ thκ shκariσμ di‐ rκθtiτσ. Thκ miθrτstruθturκ is vκry iσhτmτμκσκτus aσd thκ μraiσ sizκ variκs λrτm ρτθatiτσ tτ ρτθatiτσ. Thκ iσhτmτμκσκτus σaturκ τλ thκ miθrτstruθturκ may rκλρκθt thκ θτarsκ μraiσ sizκ ~ mm priτr tτ EC“P. Thκ μraiσs suηsκquκσtρy κvτρvκ upτσ suηsκquκσt EC“P passκs iσtτ a rκa‐ sτσaηρy κquiaxκd aσd hτmτμκσκτus miθrτstruθturκ with aσ avκraμκ μraiσ sizκ τλ ~ m rκ‐ μardρκss τλ thκ partiθuρar EC“P rτutκs. Thκ miθrτstruθturκ is κssκσtiaρρy hτmτμκσκτus aλtκr λτur EC“P passκs, aρthτuμh a tκσdκσθy λτr μraiσ κρτσμatiτσ iσ thκ dirκθtiτσ τλ thκ shκar dirκθ‐

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

tiτσ τλ thκ ρast prκssiσμ τpκratiτσ is rκtaiσκd. Fiμurκ μivκs aσ κxampρκ τλ thκ miθrτstruθturκ iσ thκ θrτss-sκθtiτσ στrmaρ tτ thκ prκssiσμ dirκθtiτσ aλtκr λτur suηsκquκσt EC“P passκs pκr‐ λτrmκd iσ diλλκrκσt rτutκs. TEM miθrτμraphs iσ Fiμurκ μivκ aσ κxampρκ τλ thκ miθrτstruθ‐ turκ iσ θrτss-sκθtiτσ aλtκr λτur aσd κiμht suηsκquκσt EC“P passκs ηy rτutκ ”θ aσd C, rκspκθtivκρy. Thκ E”SD μraiσ maps iσ Fiμurκ iσdiθatκ ρittρκ dκpκσdκσθκ τλ thκ μraiσ ητuσ‐ dary disτriκσtatiτσ distriηutiτσ τσ thκ EC“Pκd “ρ prτθκssκd ηy rτutκ ”θ.

Figure 6. TEM micrographs of al”mini”m af“er fo”r s”bseq”en“ ECAP passes on ro”“e (a) A, and (b) B.

Figure 7. Typical micros“r”c“”res and associa“ed SAED pa““erns af“er passage “hro”gh “he die for (a) 4 pressings, ro”“e B and (b) 8 pressings, ro”“e C.

Figure 8. Grain maps for ECAPed Al af“er: (a) 4 passes, and (b) 8 passes by ro”“e B (EBSD).

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Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

Θt θaσ ηκ κxpκθtκd that thκ θrκκp ηκhaviτur τλ thκ uρtraλiσκ-μraiσκd purκ aρumiσium wiρρ θriti‐ θaρρy dκpκσd τσ thκ thκrmaρ staηiρity τλ thκ miθrτstruθturκ. Tτ κxpρτrκ thκ thκrmaρ staηiρity τλ EC“P prτθκssκd aρumiσium ρτad-ρκss aσσκaρiσμ was θτσduθtκd at tκmpκraturκ τλ K λτr diλλκrκσt pκriτds τλ timκ i.κ. at thκ tκmpκraturκ τλ thκ iσtκσdκd θrκκp tκsts . Miθrτsθτpiθ κx‐ amiσatiτσ rκvκaρκd that thκ pτst-EC“P aσσκaρiσμ maπκs thκ EC“P miθrτstruθturκ quitκ uσ‐ staηρκ aσd a στtiθκaηρκ μraiσ μrτwth τθθurs at thκ vκry ηκμiσσiσμ τλ aσσκaρiσμ Taηρκ . Simuρtaσκτusρy, aσσκaρiσμ at K μivκs mκasuraηρκ θhaσμκ iσ thκ Viθπκrs miθrτhardσκss. Annealing conditions

ECAP 4 passes route A grain size [μm]

microhardness

ECAP 4 passes route B grain size [μm]

HV5

microhardness HV5

no annealing

0.9

37

0.9

38

473 K/ 0.5 h

6.6

27

4.5

32

473 K/ 1 h

7.9

23

4.8

32

473 K/ 2 h

7.3

23

4.8

27

473 K/ 5 h

7.3

21

5.3

27

473 K/ 24 h

12.2

19

5.0

23

473 K/ 168h

13.4

18

10.4

21

Table 1. Thermal s“abili“y and Vickers microhardness of “he ECAP al”mini”m.

. . . Preθipitation-strengthened aluminium alloys Θσ κvaρuatiσμ thκ miθrτstruθturκ θharaθtκristiθs τλ uρtraλiσκ-μraiσκd matκriaρs prτθκssκd ηy EC“P at κρκvatκd aσd hiμh tκmpκraturκs, it is vκry impτrtaσt tτ rκθτμσizκ that thκsκ uρtraλiσκμraiσκd miθrτstruθturκs arκ λrκquκσtρy uσstaηρκ at thκsκ tκmpκraturκs as it was οust dκmτσ‐ stratκd ηy thκ aητvκ mκσtiτσκd rκsuρts τλ thκrmaρ iσstaηiρity τλ prκssκd purκ aρumiσium. Hτwκvκr, it is τλtκσ λκasiηρκ tτ rκtaiσ aσ array τλ uρtraλiσκ μraiσs κvκσ at vκry hiμh tκmpκra‐ turκs ηy usiσμ matκriaρs θτσtaiσiσμ sκθτσd phasκs τr arrays τλ prκθipitatκs. This was a rκasτσ why twτ prκθipitatiτσ-strκσμthκσκd aρumiσium aρρτys wκrκ usκd iσ this iσvκstiμatiτσ. Θt has ηκκσ shτwσ that additiτσ tτ aρumiσium aρρτys τλ κvκσ vκry smaρρ amτuσts τλ Sθ typi‐ θaρρy, ~ . wt.% strτσμρy imprτvκs thκ miθrτstruθturκs τλ thκ aρρτys aσd thκir mκθhaσiθaρ prτpκrtiκs sτ that thκsκ aρρτys arκ suitaηρκ λτr usκ iσ κσμiσκκriσμ appρiθatiτσs [ ]. Sθaσdium additiτσs τλ ~ . wt.%Sθ tτ purκ aρumiσium arκ suλλiθiκσt tτ mτrκ τr ρκss rκtaiσ a smaρρ μraiσ sizκ at κρκvatκd tκmpκraturκs [ ]. Furthκr, sτmκ rκpτrts havκ dκmτσstratκd that it is pτssi‐ ηρκ tτ aθhiκvκ hiμh duθtiρitiκs iσ “ρ-Mμ-Sθ aρρτys ηy usiσμ EC“P tτ iσtrτduθκ aσ κxθκptiτσ‐ aρρy smaρρ μraiσ sizκ [ ]. Thκ θrκκp ηκhaviτur τλ θτσvκσtiτσaρ “ρ-Mμ aρρτys is κxtκσsivκρy dκsθriηκd iσ thκ ρitκraturκ. Thκ syσκrμy τλ sτρid-sτρutiτσ strκσμthκσiσμ aσd prκθipitatκ strκσμthκσiσμ has, hτwκvκr, στt ηκκσ κxtκσsivκρy studiκd at κρκvatκd aσd hiμh tκmpκraturκs [ ]. Vκry ρittρκ iσλτrmatiτσ is avaiρaηρκ at prκsκσt τσ thκ θrκκp prτpκrtiκs τλ uρtraλiσκμraiσκd “ρ-Sθ aσd “ρ-Mμ-Sθ aρρτys [ - ]. “θθτrdiσμρy, thκ prκsκσt iσvκstiμatiτσ was iσiti‐ atκd tτ prτvidκ a mτrκ θτmpρκx iσλτrmatiτσ τσ thκ θrκκp ηκhaviτur τλ thκsκ aρumiσium aρρτys iσ thκir uρtraλiσκ-μraiσκd statκs.

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

“σ “ρ- . wt.%Sθ aρρτy was prτduθκd ηy diρutiσμ aσ “ρ- . wt.%Sθ mastκr aρρτy with . wt.% purκ aρumiσium. Thκ rκsuρtiσμ iσμτts wκrκ suηοκθtκd tτ a hτmτμκσizatiτσ aσd μraiσ-θτarsκσiσμ trκatmκσt at K λτr hτurs aσd thκσ aμκd iσ air at K λτr hτur. Θσ thκ as-λaηriθatκd θτσditiτσ, thκ κxtrκmκρy θτarsκ μraiσ sizκ was mκasurκd as ~ mm. Thκ EC“P was θτσduθtκd at thκ Θσstitutκ τλ Physiθs τλ Matκriaρs “S CR ”rστ, Czκθh Rκpuηρiθ, usiσμ thκ samκ diκ aσd prτθκdurκ as it was rκpτrtκd κarρiκr λτr purκ aρumiσium i.κ. up tτ a tτtaρ EC“P passκs at rττm tκmpκraturκ . Thκ dκtaiρs θτσθκrσiσμ aσ “ρ- . wt.%Sθ aρρτy havκ ηκκσ rκpτrtκd κρsκwhκrκ [ - ]. Thκ tκrσary “ρ-Mμ-Sθ aρρτy was λaηriθatκd at thκ Dκ‐ partmκσt τλ Matκriaρs Sθiκσθκ aσd Eσμiσκκriσμ, Faθuρty τλ Eσμiσκκriσμ, Kyushu Uσivκrsity, Fuπuτπa, Ιapaσ. Thκ aρρτy θτσtaiσκd wt.%Mμ aσd . wt.%Sθ aσd it was prκparκd λrτm . % purity “ρ, . % purity Sθ aσd . % purity Mμ. Fuρρ dκtaiρs τσ thκ λaηriθatiτσ prτ‐ θκdurκ arκ μivκσ κρsκwhκrκ [ ] ηut, ηriκλρy, thκ aρρτy was θast, hτmτμκσizκd iσ air λτr h at K aσd sτρutiτσ trκatκd λτr h at K. Θσ thκ as-λaηriθatκd θτσditiτσ, thκ μraiσ sizκ was aητut m. “μaiσ, thκ EC“P was θτσduθtκd usiσμ a sτρid diκ that had ° aσμρκ ηκ‐ twκκσ thκ diκ θhaσσκρs aσd κaθh sampρκ was prκssκd at rττm tκmpκraturκ rκpκtitivκρy λτr a tτtaρ τλ κiμht passκs ηy rτutκ ”C.

Figure 9. Micros“r”c“”re in “he Al-0.2w“.%Sc alloy: (a) and (b) af“er ECAP (BC, 8 passes) and annealing for 1 h a“ 623 K, (c) and (d) af“er creep a“ 473 K.

Fiμurκs a,η aσd a,η shτw thκ miθrτstruθturκ τλ “ρ- . wt.%Sθ aσd “ρ- wt.%Mμ- . wt.%Sθ aρρτys iσ thκir as-prκssκd statκs. Expκrimκσts τσ “ρ- . wt.%Sθ aσd “ρ- wt.%Mμ- . wt.%Sθ aρρτys rκvκaρκd that prτθκssiσμ ηy EC“P rκduθκd thκ μraiσ sizκ tτ ~ . m aσd suηsκquκσt aσσκaρiσμ at K aσd h aσd θrκκp tκstiσμ μavκ thκ μraiσ sizκs ~ . m λτr aσ “ρ- . wt. %Sθ aρρτy aσd ~ . m λτr aσ “ρ- wt.%Mμ- . wt.%Sθ aρρτy, rκspκθtivκρy. Fiμurκs θ,d aσd

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Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

θ,d μivκ κxampρκs τλ thκ miθrτstruθturκ τλ thκ aρρτys iσ thκ ρτσμitudiσaρ sκθtiτσs paraρρκρ tτ thκ prκssiσμ dirκθtiτσ aλtκr θrκκp κxpτsurκs at K. “s wiρρ ηκ shτwσ ρatκr τσ στ suη‐ staσtiaρ diλλκrκσθκ iσ thκ rκρativκ λraθtiτσs τλ hiμh-aσμρκ > ° μraiσ ητuσdary pτpuρatiτσ aλtκr EC“P was λτuσd ηκtwκκσ thκ aρρτys iσvκstiμatκd. Thκsκ λraθtiτσs wκrκ sρiμhtρy iσ‐ θrκasκd duriσμ θrκκp κxpτsurκ up tτ aσ avκraμκ vaρuκ ~ %.

Figure 10. Micros“r”c“”re in “he Al-3w“.%Mg-0.2w“.%Sc alloy: (a) and (b) af“er ECAP (BC, 8 passes) and annealing for 1 h a“ 623 K, (c) and (d) af“er creep a“ 473 K.

Figure 11. TEM micrograph showing “he presence of coheren“ Al3Sc precipi“a“es in ”npressed sample, and (b) precipi‐ “a“e size dis“rib”“ion in ”npressed sample.

Fiμurκs η,d aσd η,d κxhiηit TEM miθrτμraphs, whiθh dκmτσstratκ thκ prκsκσθκ τλ θτhκr‐ κσt “ρ Sθ prκθipitatκs withiσ thκ matriθκs τλ ητth aρρτys. “ρ Sθ prκθipitatκs arκ iσdiθatκd ηy a

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

θτhκrκσθy straiσ θτσtrast [ ]. “ mκaσ sizκ τλ prκθipitatκs was ~ σm aλtκr θrκκp tκstiσμ τλ thκ “ρ- wt.%Mμ- . wt.%Sθ aρρτy aσd a mκaσ sizκ τλ prκθipitatκs sρiμhtρy ρarμκ was rκθτrdκd λτr thκ “ρ- . wt.%Sθ aρρτy ~ σm [ ] . Fiμurκ d shτws disρτθatiτσ miθrτstruθturκ τη‐ sκrvκd aλtκr θrκκp κxpτsurκ τλ EC“Pκd “ρ- wt.%Mμ- . wt.%Sθ. Thκ disρτθatiτσ pairs prκsκσt iσ ητth aρρτys θτσtaiσiσμ thκ smaρρκst prκθipitatκ radii arκ vκry λrκquκσt. Fτr ρarμκr prκθipitatκs thκ disρτθatiτσs arκ piσσκd κλλiθiκσtρy ηy “ρ Sθ prκθipitatκs as θρimηiσμ ηκθτmκs sρτwκr. Fiμurκ a κxhiηits TEM miθrτμraph τλ aσ “ρ- wt.%Mμ- . wt.%Sθ aρρτy shτwiσμ thκ prκsκσθκ τλ θτhκrκσt “ρ Sθ prκθipitatκs iσ aσ uσprκssκd sampρκ, aσd Fiμurκ η prκsκσts prκθipitatκ sizκ distriηutiτσ iσ aσ uσprκssκd aρρτy. . . Microstructure developed during creep . . . Pure aluminium Θt θaσ ηκ κxpκθtκd that thκ θrκκp ηκhaviτur τλ thκ UFG matκriaρ wiρρ ηκ iσλρuκσθκd θritiθaρρy upτσ thκ suηsκquκσt thκrmaρ staηiρity τλ its miθrτstruθturκ. Tτ κxpρτrκ this κλλκθt miθrτsθτp‐ iθ κxamiσatiτσ τλ μraiσ sizκ θhaσμκ iσ purκ aρumiσium duriσμ θrκκp κxpτsurκ at K aσd MPa wκrκ pκrλτrmκd. Θt is impτrtaσt tτ στtκ that κaθh θrκκp spκθimκσ was hκatκd tτ thκ tκstiσμ tκmpκraturκ iσ thκ λurσaθκ τλ thκ θrκκp tκstiσμ maθhiσκ τvκr a pκriτd τλ ~ h aσd thκσ hκρd at thκ tκstiσμ tκmpκraturκ λτr λurthκr ~ h iσ τrdκr tτ rκaθh thκrmaρ κquiρiηrium. Cτσsκquκσtρy, thκ miθrτstruθturκ θharaθtκristiθs τλ thκ EC“P matκriaρ at thκ τσsκt τλ thκ θrκκp tκstiσμ wκrκ simiρar tτ that shτwσ iσ Taηρκ . Nτ suηstaσtiaρ θτarsκσiσμ τλ μraiσs has ηκκσ τηsκrvκd duriσμ θrκκp κxpτsurκ at K sκκ Taηρκ . Specimen

ECAP conditions

Grain size [μm]

Time to fracture [h]

A4

ro”“e A, 4 passes

6.4

79

A8

ro”“e A, 8 passes

7.0

26

A12

ro”“e A, 12 passes

6.7

17

B4

ro”“e B, 4 passes

8.7

62

B8

ro”“e B, 8 passes

7.2

60

B12

ro”“e B, 12 passes

8.8

39

Table 2. Grain size of “he ECAP ma“erial af“er creep a“ 473 K and 15 MPa.

TEM τηsκrvatiτσs wκrκ usκd aρsτ tτ κstaηρishκd dκtaiρs τλ miθrτstruθturκ κvτρutiτσ duriσμ θrκκp. Thκ miθrτμraphs iσ Fiμurκ a,η iρρustratκ a disρτθatiτσ suηstruθturκ iσsidκ thκ μraiσs. Thκ disρτθatiτσ ρiσκs wκrκ wavy aσd τθθasiτσaρρy taσμρκd with κaθh τthκr. Θt is πστw that ρarμκ μraiσs iσ UFG matκriaρs θτσtaiσ disρτθatiτσs whiρκ μraiσs smaρρκr thaσ a θκrtaiσ sizκ arκ disρτθatiτσ λrκκ [ , ]. E”SD mκasurκmκσts wκrκ taπκσ tτ dκtκrmiσκ thκ μraiσ ητuσdary misτriκσtatiτσ aσd thκ vaρuκ τλ rκρativκ λraθtiτσ τλ a hiμh-aσμρκ μraiσ ητuσdary > ° pτpuρatiτσ λτr dκtaiρs sκκ . . . .

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Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

Figure 12. TEM micrographs from “he longi“”dinal sec“ion of an al”mini”m processed by ECAP ro”“e Bc (a) af“er 1 ECAP pass and creep, (b) af“er 8 ECAP passes and creep. Creep a“ 473 K and 15 MPa.

. . . Preθipitation-strengthened alloys Fτr θτmparisτσ rκasτσs, sτmκ rκsuρts τλ miθrτstruθturaρ θhaσμκs iσ “ρ- . wt.%Sθ aσd “ρ- wt. %Mμ- . wt.%Sθ aρρτys duriσμ θrκκp wκrκ prκsκσtκd κarρiκr iσ . . . Θt was λτuσd that θrκκp κx‐ pτsurκs τλ aσ “ρ- . wt.%Sθ aρρτy at K aσd MPa θausκd thκ θhaσμκs iσ suη μraiσ sizκs iσ‐ itiaρρy rκsuρtiσμ λrτm EC“P prκssiσμ. Fiμurκ a shτws thκ miθrτstruθturκ aλtκr EC“P passκs aσd suηsκquκσt θrκκp κxpτsurκ. TEM aσaρysis rκvκaρκd that thκ avκraμκ suη μraiσ sizκ iσ‐ θrκasκs λrτm ~ . um tτ ~ . m aλtκr θrκκp κxpτsurκ. Thκ suη μraiσ μrτwth was κλλκθtκd ηy prκsκσθκ τλ θτhκrκσt “ρ Sθ prκθipitatκs Fiμurκ η whiθh tτ sτmκ κxtκσt piσσκd thκ ητuσda‐ riκs aμaiσst thκir miμratiτσ aσd rκstriθtκd thκ mτvκmκσt τλ disρτθatiτσ.

Figure 13. Micros“r”c“”re of Al-0.2w“.%Sc alloy af“er 8 ECAP passes and s”bseq”en“ creep expos”re a“ 473 K and 20 MPa. (a) micros“r”c“”re, and (b) precipi“a“es Al3Sc.

Thκ E”SD data iσdiθatκ that thκ σumηκr τλ hiμh aσμρκ-ητuσdariκs > ° mκasurκd iσ thκ spκθimκσs aλtκr EC“P aσd suηsκquκσt θrκκp κxpτsurκ is strτσμρy dκpκσdκσt τσ thκ σumηκr τλ EC“P passκs. Thκ σumηκr τλ hiμh-aσμρκ μraiσ ητuσdariκs is iσθrκasiσμ with iσθrκasiσμ σumηκr τλ EC“P passκs λrτm apprτximatκρy % iσ thκ spκθimκσ aλtκr EC“P pass aσd suη‐ sκquκσt θrκκp tτ ~ % iσ thκ spκθimκσ aλtκr EC“P passκs aσd suηsκquκσt θrκκp. Θt was rκpτrtκd [ ] that thκ μraiσ ητuσdary sρidiσμ θaσ τθθur iσ UFG matκriaρs at κρκvatκd tκmpκra‐ turκs. Thus wκ θaσ suppτsκ that θhaσμκs iσ thκ σumηκr τλ hiμh-aσμρκ μraiσ ητuσdariκs iσ

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

thκ miθrτstruθturκ τλ EC“Pκd matκriaρs duriσμ θrκκp tκsts θaσ aλλκθt thκir θrκκp ηκhaviτur ηy iσθrκasiσμ thκ θτσtriηutiτσ τλ μraiσ ητuσdary sρidiσμ tτ thκ tτtaρ θrκκp straiσ [ ]. Thκ E”SD aσaρysκs wκrκ pκrλτrmκd τσ thκ sκvκraρ pρaθκs τλ thκ μauμκ ρκσμth τλ θrκκp spκθi‐ mκσ aλtκr EC“P aσd suηsκquκσt θrκκp rκvκaρκd sθattκr iσ thκ σumηκr τλ hiμh aσμρκ μraiσ ητuσdariκs H“G”s . Θσ thκ Fiμurκ thκ miσimaρ aσd maximaρ mκasurκd vaρuκs τλ thκ σumηκr τλ H“G”s arκ pρτttκd. Thκ iσspκθtiτσ τλ Fiμurκ shτws that thκ sθattκr iσ H“G”s θaσ ηκ partiθuρarρy κxpκθtκd aλtκr θrκκp tκsts iσ thκ spκθimκσs with ρτwκr σumηκr τλ EC“P passκs. Thκ hκtκrτμκσκτus distriηutiτσ τλ H“G” θaσ prτηaηρy iσλρuκσθκ thκ hτmτμκσκity τλ μraiσ ητuσdary sρidiσμ. Θσ thκ arκas with thκ hiμhκr σumηκr τλ H“G”s thκ μraiσ ητuσdary sρidiσμ wiρρ ηκ mτrκ iσtκσsivκ thaσ iσ thκ surrτuσdiσμ arκas [ ].

Figure 14. Frac“ion of high angle grain bo”ndaries as a f”nc“ion of “he n”mber of ECAP passes in “he Al-0.2w“.%Sc alloy.

Thκ iσvκstiμatiτσ τλ thκ uσκtθhκd surλaθκs τλ thκ spκθimκσs aλtκr - EC“P passκs aσd aλtκr θrκκp κxpτsurκ rκvκaρκd thκ appκaraσθκ τλ mκsτsθτpiθ shκar ηaσds [ , , , - ] ρyiσμ σκar tτ thκ shκar pρaσκ τλ thκ ρast EC“P pass Fiμurκ . Oσ thκ surλaθκ τλ spκθimκσs thκ mκsτsθτpiθ shκar ηaσds wκrκ partiθuρarρy τηsκrvκd σκar thκ λraθturκ rκμiτσ aσd thκir λrκ‐ quκσθy dκθrκasκd rapidρy with iσθrκasiσμ distaσθκ λrτm thκ λraθturκ. Oσ thκ spκθimκσ sur‐ λaθκ aλtκr EC“P passκs thκ mκsτsθτpiθ shκar ηaσds aρrκady θτvκrκd aρmτst thκ whτρκ μauμκ ρκσμth. Θt was λτuσd that thκ width τλ thκ ηaσds dκθrκasκs with iσθrκasiσμ σumηκr τλ EC“P passiσμ aσd aλtκr EC“P passκs thκ avκraμκ width τλ thκ ηaσds was ~ m as it is shτwσ iσ Fiμurκ . Thκ aσaρysκs τλ miθrτstruθturκ τσ thκ iσtκrλaθκs τλ thκ ηaσds λτuσd that iσ thκ viθiσity τλ thκsκ iσtκrλaθκs hiμh hκtκrτμκσκity iσ thκ distriηutiτσ τλ H“G”s θaσ ηκ τη‐ sκrvκd Fiμurκ . Thκ λτrmatiτσ τλ thκ mκsτsθτpiθ shκar ηaσd θaσ ηκ rκρatκd tτ iσhτmτμκ‐ σκity τλ miθrτstruθturκ τλ EC“Pκd aρρτy aλtκr θrκκp κxpτsurκ. Examiσatiτσ ηy E”SD rκvκaρκd that thκ miθrτstruθturκ τλ mκsτsθτpiθ shκar ηaσds is θrκatκd ηy hiμh-aσμρκ μraiσ ητuσdariκs Fiμurκ aσd .

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Figure 15. The he“erogeneo”s dis“rib”“ion of HAGBs (red colo”red) in “he sample of an Al-0.2w“.%Sc alloy af“er 4 ECAP passes and creep a“ 473 K and 20 MPa.

Figure 16. Appearance of “he micros“r”c“”re in “he Al-0.2w“%Sc alloy af“er 2 ECAP passes and s”bseq”en“ creep a“ 473 K. Tensile axis is horizon“al, SEM.

. . Unique features of microstructure in ultrafine-grained materials Thκ prτθκssiσμ tκθhσiquκ usκd tτ τηtaiσ thκ UFG miθrτstruθturκ shτuρd strτσμρy iσλρuκσθκ thκ θrκκp prτpκrtiκs τλ thκ matκriaρ. This is primariρy duκ tτ diλλκrκσθκ iσ miθrτstruθturκ as distriηutiτσ τλ μraiσs, suημraiσs, disρτθatiτσ dκσsity aσd ητuσdary θharaθtκr. Thκ μraiσ ητuσdary θharaθtκr is usuaρρy quaσtiλiκd usiσμ thκ misτriκσtatiτσ aσμρκ aθrτss μraiσ ητuσdariκs, with hiμh aσd ρτw aσμρκ μraiσ ητuσdariκs dκλiσκd as ≥ ° aσ ° < < °,

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rκspκθtivκρy. Eρκθtrτσ ηaθπ sθattκr diλλraθtiτσs E”SD mappiσμ has ηκκσ usκd tτ quaσtita‐ tivκρy θharaθtκrizκ ητuσdariκs iσ UFG matκriaρs [ , , , , ]. “ρthτuμh thκ ητuσdary spaθiσμ saturatκs aλtκr thκ λirst λκw EC“P passκs, thκ λraθtiτσ τλ hiμh aσμρκ ητuσdariκs θτσ‐ tiσuκs tτ iσθrκasκ with iσθrκasiσμ EC“P passκs [ , , ]. Θσ additiτσ tτ μraiσ sizκ dκtκrmi‐ σatiτσ, thκrκ arκ a σumηκr τλ impτrtaσt miθrτstruθturaρ paramκtκrs κvaρuatκd λrτm E”SD ηut στt avaiρaηρκ λrτm θτσvκσtiτσaρ mκthτds τλ μraiσ θharaθtκrizatiτσ iσ partiθuρars param‐ κtκrs rκρatiσμ tτ thκ μraiσ τriκσtatiτσs aσd ητuσdary θharaθtκrs [ - ]. Thκ λτρρτwiσμ tκxt dκsθriηκs rκprκsκσtativκ rκsuρts τλ quaσtitativκ θharaθtκrizatiτσ τλ UFG miθrτstruθturκ. . . . Stereologiθal estimates of UFG miθrostruθture θharaθteristiθs “t κaθh κxamiσκd spκθimκσ thκrκ wκrκ madκ thrκκ mutuaρρy pκrpκσdiθuρar pρaσar mκtaρρτ‐ μraphiθ sκθtiτσs dκστtκd as ΨΩ, ΨZ ρτσμitudiσaρ sκθtiτσs aσd ΩZ traσsvκrsκ sκθtiτσ , whκrκ Ψ, Ω aσd Z arκ thκ axκs τλ thκ Cartκsiaσ θττrdiσatκ systκm with Ψ aρτσμ thκ ρast prκss‐ iσμ dirκθtiτσ aσd Z pκrpκσdiθuρar tτ thκ ητttτm τλ thκ θhaσσκρ. Thκ tκθhσiquκ τλ autτmatκd E”SD iσ thκ sθaσσiσμ κρκθtrτσ miθrτsθτpκ was usκd λτr quaσtitativκ mκtaρρτμraphy. Fτur raσμκs τλ thκ ητuσdary misτriκσtatiτσ ∆ wκrκ sκρκθtκd ° ∆, ° ∆, ° ∆ aσd ° ∆. Thκσ staσdard iσtκrθκpt θτuσtiσμ [ ] rκsuρtiσμ iσ thκ mκaσ σumηκr NL τλ prτλiρκ θhτrds pκr uσit ρκσμth τλ thκ κxamiσκd tκst ρiσκs was θarriκd τut. Θσ κaθh spκθimκσ, six systκmatiθaρρy sκρκθtκd dirκθtiτσs τλ thκ tκst ρiσκs iσ κaθh sκθtiτσ wκrκ κxamiσκd. Thκ mκaσ ητuσdary arκas uσit vτρumκ wκrκ thκσ κstimatκd ηy thκ stκrκτρτμiθaρ rκρatiτσ SV = [ NL]. “στthκr impτrtaσt λκaturκ τλ thκ μraiσ ητuσdary struθturκ is its iσhτmτμκσκity. Thκ dispκrsiτσ τλ μraiσ prτλiρκ arκas θaσ ηκ quaρiλiκd ηy thκ θτκλλiθiκσt τλ variatiτσ CVa τλ thκ μraiσ prτλiρκ arκas iσ a pρaσκ V CVa = ¯ , whκrκ V is μraiσ prτλiρκ arκas variatiτσ aσd ϖ¯ is thκ mκaσ vaρuκ τλ thκ μraiσ prτ‐ ϖ λiρκ arκa [ , , ]. Thκ θτκλλiθiκσt τλ variatiτσ CVa τλ thκ prτλiρκ arκas is pκrhaps thκ ηκst stκrκτmκtriθ θharaθtκristiθ tτ κvaρuatκ hτmτμκσκity τλ miθrτstruθturκ aσd στwadays it is rκρativκρy κasiρy attaiσaηρκ ηy a θτmputκr imaμκ aσaρysis [ ]. . . . Inhomogeneity of UFG miθrostruθture Thκrκ arκ σumκrτus rκpτrts τλ thκ prτθκssiσμ τλ variτus purκ mκtaρs aσd mκtaρρiθ aρρτys ηy EC“P aσd maσy τλ thκsκ rκpτrts iσvτρvκ a dκtaiρκd θharaθtκrizatiτσ τλ thκ miθrτstruθturκ. Thκsκ rκsuρts arκ summarizκd iσ rκθκσt rκviκws [ , ]. Hτwκvκr, iσλτrmatiτσ sκρdτm is rκpτrt‐ κd τσ thκ pκrθκσtaμκ τλ hiμh aσμρκ μraiσ ητuσdariκs H“G”´s , aσ impτrtaσt paramκtκr iσ thκ θτmparisτσ τλ pρastiθity τλ diλλκrκσt prτθκssiσμ rτutκs aσd matκriaρs [ ]. Θt θaσ ηκ κxpκθtκd that sampρκs with diλλκrκσt distriηutiτσs τλ misτriκσtatiτσ aθrτss thκ μraiσ ητuσdariκs wiρρ dκ‐ λτrm diλλκrκσtρy. Furthκr, tτ prτvidκ iσλτrmatiτσ τσ thκ τptimum miθrτstruθturκ τλ UFG ma‐ tκriaρs wκ σκκd tτ usκ aσ additiτσaρ quaσtitativκ miθrτstruθturaρ paramκtκr τthκr thaσ οust thκ avκraμκ μraiσ sizκ θritiθaρ λτr thκ θrκκp ηκhaviτur aσd prτpκrtiκs [ ]. Suθh paramκtκr θτuρd ηκ a θτκλλiθiκσt τλ prτλiρκ CVa as a mκasurκ τλ hτmτμκσκity τλ matκriaρs miθrτstruθturκ [ ]. Hκσθκ, thκ μraiσ aσd suημraiσ struθturκ τλ thκ θrκκp spκθimκσs was rκvκaρκd ηy mκaσs τλ E”SD aσd θharaθtκrizκd ηy thκ θτκλλiθiκσt τλ variatiτσ CVa τλ thκ prτλiρκ arκas. Fτur raσμκs τλ thκ ητuσdary misτriκσtatiτσ ∆ ηκtwκκσ adοaθκσt pixκρs wκrκ sκρκθtκd λτr κxamiσatiτσ usiσμ

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E”SD, whiθh θτrrκspτσd σamκρy tτ suηητuσdariκs, traσsitivκ aσd hiμh aσμρκ μraiσ ητuσda‐ riκs withiσ ° ∆ aσd ° ∆, traσsitivκ aσd hiμh aσμρκ μraiσ ητuσdariκs λτr ° ∆, aσd mτstρy μraiσs with H“G”´s λτr ∆ ≥ °. Sκρκθtκd κxampρκs τλ imaμκs τλ ΨZ sκθtiτσs prτduθκd ηy E”SD τλ aσ “ρ- . wt.%Sθ arκ shτwσ iσ Fiμurκ .

Figure 17. Selec“ed examples of EBSD grain maps of an Al-0.2w“.%Sc alloys af“er ECAP cons“r”c“ed for differen“ grain misorien“a“ions: (a) s”bbo”ndaries ∆ 2°, (b) “ransi“ive s”bbo”ndaries and high angle bo”ndaries ∆ 10°, and, (c) high-angle grain bo”ndaries ∆ 15°.

Figure 18. The frac“ion of high-angle grain bo”ndaries in “he crep“ samples as a f”nc“ion of “he n”mber of ECAP passes.

Θt was μκσκraρρy τηsκrvκd that with thκ iσθrκasiσμ σumηκr τλ EC“P passκs N, a θτσsidκraηρκ amτuσt τλ suημraiσ ητuσdariκs was μraduaρρy traσsλτrmκd tτ H“G”´s as shτwσ iσ Fiμurκ . “t thκ samκ timκ, thκ ρτθaρ hτmτμκσκity τλ struθturκ as θharaθtκrizκd ηy thκ vaρuκs τλ CVa with thκ iσθrκasiσμ σumηκr N is μraduaρρy imprτvκd as dκmτσstratκs ηy Fiμurκ . Fiμ‐

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

urκ aρsτ shτws thκ miθrτsθτpiθ appκaraσθκ τλ thκ spκθimκσs τλ aσ “ρ- . wt.%Sθ aρρτy θrκpt uσdκr thκ samκ ρτadiσμ θτσditiτσs K, MPa ηut prτθκssκd ηy diλλκrκσt σum‐ ηκrs τλ EC“P passκs N. Thκ vaρuκs τλ CVa as hiμh as at N = , CVa< at N = , aσd . CVa at N = wκrκ λτuσd. Extrκmκρy hiμh vaρuκ CVa at N = dκmτσstratκs vκry hiμh iσhτmτμκσκity τλ a mixturκ τλ suημraiσ aσd μraiσ struθturκs. Thκ vaρuκ τλ CVa iσ vκry hτ‐ mτμκσκτus μraiσ systκms shτuρd στt κxθκκd thκ vaρuκ τλ [ ]. Θt shτuρd ηκ στtκd that κx‐ trκmκρy hiμh vaρuκs τλ thκ θτκλλiθiκσt τλ variatiτσ CVa is a σaturaρ θτσsκquκσθκ τλ thκ shτrt as wκρρ as ρτσμ-raσμκ iσhτmτμκσκity τλ miθrτstruθturκ.

Figure 19. Grain maps of an Al-0.2w“.%Sc alloy processed by differen“ n”mber N of ECAP passes and crep“ a“ 473 K and 20 MPa, and corresponding parame“er CVa: (a) 2 passes, CVa>> 2, (b) 4 passes, CVa< 2 and, (c) 8 passes, 0.55 CVa< 1.

Thκ suηstaσtiaρ μraiσ θτarsκσiσμ κspκθiaρρy iσ thκ θasκ τλ purκ mκtaρs θamκ up duriσμ thκ θrκκp κxpτsurκs dκpκσdiσμ τσ strκss aσd tκmpκraturκ thus maσiλκstiσμ thκ thκrmaρ iσstaηiρ‐ ity τλ uρtraλiσκ-μraiσκd miθrτstruθturκ [ , , ]. Θt is θρκar that iσ purκ aρumiσium thκ μraiσs μrτw rapidρy at κρκvatκd tκmpκraturκs ηκθausκ thκrκ arκ στ prκθipitatκs withiσ thκ θrystaρ‐ ρiσκ ρattiθκ tτ rκstriθt thκ mτvκmκσt τλ thκ μraiσ ητuσdariκs ηy a piσσiσμ κλλκθt€. ”y θτσ‐ trast, suηmiθrτmκtκr μraiσs may ηκ rκtaiσκd tτ rκρativκρy hiμh tκmpκraturκs iσ matκriaρs θτσtaiσiσμ a distriηutiτσ τλ λiσκ prκθipitatκs as iσ thκ θasκ τλ aσ “ρ- . %Sθ aρρτys θτσtaiσiσμ “ρ Sθ prκθipitatκs [ ]. Thκ quaσtitativκ θharaθtκrizatiτσ τλ thκ iσhτmτμκσκity τλ thκ ητuσ‐ dary struθturκ is shτwσ iσ Fiμurκ . Θt shτuρd ηκ strκssκd that thκ vaρuκs τλ thκ θτκλλiθiκσt τλ prτλiρκ arκa CVa as a mκasurκ τλ struθturκ hτmτμκσκity strτσμρy dκpκσd τσ thκ θhτsκσ raσμκs τλ misτriκσtatiτσ ∆ iσ E”SD aσaρysis. Whκrκas thκ λraθtiτσ τλ thκ suηητuσdariκs ρτw-aσμρκ μraiσ ητuσdariκs arκ dτmiσatiσμ λτr ∆ ≥ ° Fiμurκ a , thκ λraθtiτσs τλ hiμhaσμρκ μraiσ ητuσdariκs ≥ ° θτσλirm thκir hiμh sharκ λτr thκ raσμκ τλ ∆ ≥ ° Fiμurκ η . Dκtaiρκd iσspκθtiτσ τλ Fiμurκ η shτws a strτσμ dκpκσdκσθκ τλ CVa aλtκr θrκκp τσ thκ σumηκr τλ EC“P passκs. Suηstaσtiaρ dκθrκasκ τλ thκ vaρuκs CVa ° λτr thκ prκθipitatiτσstrκσμthκσκd “ρ- . Sθ aρρτy with iσθrκasiσμ σumηκr τλ passκs N λτr ∆ ≥ ° may ηκ θτσσκθtκd with thκ mτrκ rapid κvτρutiτσ ητuσdariκs haviσμ misτriκσtatiτσ aσμρκs > ° Fiμurκ a .

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Figure 20. Coefficien“ of profile area CVa as a meas”re of homogenei“y: 0.55 CVa < 1 (homogeneo”s sys“em), and CVa >> 2 (m”l“imodal grain size dis“rib”“ion). The chosen ranges of misorien“a“ion ∆ in EBSD analysis: (a) ∆ 2°, (b) ∆ 15°.

Figure 21. Dis“rib”“ion of bo”ndaries wi“h differen“ misorien“a“ion (a) EBSD analysis for ∆ 2°, (b) ∆ 15°.

for an Al-0.2w“.%Sc alloy analysed in Fig”re 8:

. Creep behaviour of UFG aluminium and its alloys Thκ mκθhaσiθaρ prτpκrtiκs τλ ηuρπ uρtraλiσκ-μraiσκd UFG matκriaρs at κρκvatκd aσd/τr hiμh tκmpκraturκs arκ a σκw aσd impτrtaσt arκa τλ rκsκarθh [ ]. Hτwκvκr, thκrκ havκ ηκκσ τσρy a λκw iσvκstiμatiτσs τσ thκ θrκκp ηκhaviτur τλ ηuρπ UFG matκriaρs prτθκssκd ηy κquaρ-θhaσ‐ σκρ aσμuρar prκssiσμ EC“P [ , ]. ”y θτmparisτσ with thκ uσprκssκd θτarsκ-μraiσκd statκ, prτθκssiσμ ηy EC“P may ρκad tτ θτσsidκraηρκ θhaσμκs iσ thκ θrκκp prτpκrtiκs iσ ηuρπ

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

UFG matκriaρs iσθρudiσμ a dκθrκasκ aσd/τr aσ iσθrκasκ [ ] iσ thκ miσimum θrκκp ratκ aσd thκ θrκκp ρiλκ. Θt is impτrtaσt tτ στtκ that thκsκ trκσds may ηκ στtiθκaηρy dκpκσdκσt τσ thκ σumηκr τλ EC“P passκs. Maσy iσvκstiμatiτσs θτσθκrσκd with thκ idκσtiλiθatiτσ τλ θrκκp mκθhaσisms havκ ηκκσ uσdκrtaπiσμ usiσμ θτarsκ-μraiσκd purκ aρumiσium [ ] aσd θτm‐ mκrθiaρ aρumiσium aρρτys [ ]. Hτwκvκr, it is ρτμiθaρ tτ κxpκθt that thκ mκθhaσism τλ hard‐ κσiσμ/sτλtκσiσμ τηsκrvκd iσ thκ aρumiσium prτθκssκd ηy EC“P may ηκ diλλκrκσt λrτm that τηsκrvκd iσ thκ θτarsκ-μraiσκd matκriaρ. Cτσsκquκσtρy, it θaσστt ηκ κxθρudκd that θrκκp iσ thκ EC“P aρumiσium aσd its aρρτys is θτσtrτρρκd ηy diλλκrκσt θrκκp mκθhaσism s thaσ that iσ thκ θτarsκ matκriaρ. Thus, σκithκr phκστmκστρτμiθaρ στr miθrτsθτpiθ aspκθts τλ thκ θrκκp ηκhaviτur τλ matκriaρs prτθκssκd ηy EC“P havκ ηκκσ uσdκrstaσd suλλiθiκσtρy as yκt. This sκθtiτσ rκpτrts a sκriκs τλ θrκκp κxpκrimκσts that wκrκ θτσduθtκd τσ spκθimκσs τλ purκ aρumiσium aσd its “ρ- . wt.%Sθ aσd “ρ- wt.%Mμ- . wt.%Sθ aρρτys prτθκssκd ηy κquaρθhaσσκρ aσμuρar prκssiσμ. Fτr θτmparisτσ purpτsκs, sτmκ θrκκp tκsts wκrκ pκrλτrmκd aρsτ τσ thκ uσprκssκd matκriaρs. Crκκp tκsts wκrκ pκrλτrmκd ητth iσ tκσsiτσ aσd θτmprκssiτσ. . . Effect of processing route on creep behaviour “s disθussκd iσ mτrκ dκtaiρ iσ Sκθtiτσ . . λτur distiσθt prκssiσμ rτutκs havκ ηκκσ idκσtiλiκd Fiμurκ . Thκ EC“P prτθκssiσμ was θτσduθtκd ηy τσκ τr rκpκtitivκ passκs λτρρτwiσμ κithκr rτutκ “, ” rτutκ ”C was usκd τσρy τr C. Fiμurκ θτσtaiσs a θτmpρκtκ rκθτrd τλ thκ maiσ θrκκp paramκtκrs λτr thκ EC“P spκθimκσs τλ “ρ aλtκr θrκκp tκstiσμ iσ tκσsiτσ at K aσd MPa κaθh pτiσt rκprκsκσts thκ avκraμκ rκsuρts τλ twτ tτ thrκκ iσdividuaρ θrκκp tκsts at thκ samκ ρτadiσμ θτσditiτσs . Θσspκθtiτσ τλ Fiμurκ shτws thκrκ arκ στt vκry siμσiλiθaσt diλλκr‐ κσθκs iσ θrκκp prτpκrtiκs τλ spκθimκσs prκparκd ηy thκ variτus EC“P prτθκssiσμ rτutκs. “ρρ thrκκ prτθκssiσμ rτutκs prτduθκ a siμσiλiθaσt iσθrκasκ iσ thκ miσimum θrκκp ratκ thrτuμh thκ λirst λτur passκs aσd a sρiμht iσθrκasκ duriσμ suηsκquκσt prκssiσμ Fiμurκ a . ”y θτσ‐ trast, thκ timκ tτ λraθturκ θrκκp ρiλκ dramatiθaρρy drτps thrτuμh λτur passκs aσd thκσ thκrκ is στ siμσiλiθaσt diλλκrκσθκs amτσμ thκ σumηκr τλ λτρρτwiσμ passκs ª Fiμurκ η. Rκθκσtρy, attκσtiτσ has ηκκσ μivκσ tτ κλλκθtivκσκss τλ thκ variτus EC“P rτutκs iσ prτduθiσμ μraiσ rκλiσκmκσt iσ aρumiσium [ ]. Θt has ηκκσ dκmτσstratκd that EC“P is θapaηρκ τλ prτduθ‐ iσμ rκλiσκd struθturκs with ρarμκ λraθtiτσs τλ hiμh-aσμρκ ητuσdariκs [ ] aρthτuμh thκ mκθha‐ σisms iσvτρvκd iσ thκ λτrmatiτσ τλ λiσκ μraiσs aσd hiμh-aσμρκ ητuσdariκs iσ thκ dκλτrmatiτσ miθrτstruθturκ rκmaiσ tτ ηκ θρariλiκd. Θσ this wτrπ miθrτstruθturaρ iσvκstiμatiτσ aρρ rτutκs κx‐ amiσκd iσdiθatκd ρittρκ diλλκrκσθκs iσ thκ μraiσ sizκ prτduθκd via thκ variτus EC“P rτutκs. With iσθrκasiσμ σumηκr τλ EC“P passκs this diλλκrκσθκ dκθrκasκs. Furthκr, thκrκ was ρittρκ ap‐ parκσt dκpκσdκσθκ τλ thκ misτriκσtatiτσ τσ thκ variτus prτθκss rτutκ λτr aσ EC“P diκ haviσμ aσ iσtκrσaρ aσμρκ κquaρs tτ °. Thκ misτriκσtatiτσ data θτσλirmκd that rκpκtitivκ prκssiσμ rκ‐ suρts iσ a prτμrκssivκ iσθrκasκ iσ thκ λraθtiτσ τλ hiμh-aσμρκ μraiσ ητuσdariκs Fiμurκ . Θσ rκρatκd wτrπ, Sπρκσiθπa κt aρ. [ , ] θarriκd τut aσ κxtκσsivκ θrκκp tκstiσμ τσ purκ aρumi‐ σium prτθκssκd ηy variτus EC“P rτutκs. Θt was λτuσd that prτθκssiσμ rτutκ had a ρittρκ ap‐ parκσt κλλκθt τσ thκ θrκκp ηκhaviτur τλ a prκssκd aρumiσium. Hτwκvκr, thκ κλλκθt τλ μraiσ μrτwth duriσμ θrκκp may tκσd tτ τηsθurκ thκ κλλκθt τλ diλλκrκσt prτθκssiσμ rτutκs aσd thκ

23

24

Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

θrκκp κxpκrimκσts arκ prτηaηρy στt a suλλiθiκσtρy rκλiσκd prτθκdurκ λτr piθπiσμ up thκsκ rathκr smaρρ diλλκrκσθκs iσ thκ θrκκp ηκhaviτur.

Figure 22. Infl”ence of differen“ ECAP ro”“es and differen“ n”mber of ECAP passes on (a) creep ra“e, and (b) “ime “o frac“”re.

. . Creep behaviour of pure aluminium Crκκp tκsts wκrκ pκrλτrmκd τσ thκ as-prκssκd spκθimκσs ητth iσ tκσsiτσ aσd θτmprκssiτσ iσ thκ tκmpκraturκ iσtκrvaρ λrτm tτ K uσdκr aσ appρiκd strκss raσμκ ηκtwκκσ aσd MPa. Thκ suηsκquκσt EC“P passκs wκrκ pκrλτrmκd ηy rτutκ ”C sκκ part . . up tτ passκs. . . . Creep ηehaviour Rκprκsκσtativκ θrκκp θurvκs arκ shτwσ iσ Fiμurκs aσd . “ρρ τλ thκsκ pρτts wκrκ τηtaiσκd at tκmpκraturκ τλ K ~ . Tm uσdκr aσ iσitiaρ appρiκd uσiaxiaρ tκσsiρκ τr θτmprκssiτσ strκss τλ MPa. Thκ θrκκp tκsts iσ tκσsiτσ wκrκ ruσ up tτ thκ λiσaρ λraθturκ τλ thκ θrκκp spκθimκσs, whκrκas thκ θrκκp tκsts iσ θτmprκssiτσ wκrκ iσtκrruptκd at a truκ straiσ τλ aητut ~ . . Staσdard vs t θrκκp θurvκs iσ Fiμurκs a aσd a θaσ ηκ κasiρy rκpρτttκd iσ thκ λτrm τλ thκ iσstaσtaσκτus straiσ ratκ d /dt vκrsus straiσ as shτwσ iσ Fiμurκs η aσd η. “s dκmτσ‐ stratκd ηy λiμurκs, siμσiλiθaσt diλλκrκσθκs wκrκ λτuσd iσ thκ θrκκp ηκhaviτur τλ thκ EC“P matκriaρ whκσ θτmparκd tτ its θτarsκ-μraiσκd θτuσtκrpart. First, thκ EC“P matκriaρs κxhiη‐ its marπκdρy ρτσμκr θrκκp ρiλκ Fiμurκ a τr marπκdρy ρτσμκr duratiτσ τλ θrκκp κxpτsurκ tτ τηtaiσ a straiσ τλ ~ . Fiμurκ η thaσ θτarsκ μraiσκd aρumiσium. Sκθτσd, thκ miσimum θrκκp ratκ λτr thκ EC“P matκriaρ is aητut τσκ tτ twτ τrdκrs τλ maμσitudκ ρκss thaσ that τλ θτarsκ-μraiσκd matκriaρ. Third, thκ shapκs τλ tκσsiρκ θrκκp θurvκs λτr thκ EC“P matκriaρ aλ‐ tκr hiμh σumηκr τλ prκssiσμ diλλκr θτσsidκraηρy λrτm thκ tκsts θτσduθtκd at smaρρ σumηκr τλ thκ EC“P passκs ηy thκ κxtκσt τλ iσdividuaρ staμκs τλ θrκκp.

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

Figure 23. S“andard creep and creep ra“e vers”s s“rain c”rves for ”npressed s“a“e and vario”s n”mber of ECAP passes via ro”“e Bc (creep in “ension ”p “o frac“”re).

Figure 24. S“andard creep and creep ra“e vers”s s“rain c”rves for ”npressed s“a“e and vario”s n”mber ECAP passes via ro”“e Bc (creep in compression ”p “o s“rain ~ 0.35).

Thκ diλλκrκσθκ iσ thκ miσimum θrκκp ratκ λτr thκ EC“P matκriaρ aσd uσprκssκd statκ θτσsis‐ tκσtρy dκθrκasκs with iσθrκasiσμ σumηκr τλ EC“P passκs Fiμurκs η aσd η . “σ addi‐ tiτσaρ diλλκrκσθκ is iρρustratκd ηy Fiμurκ a, whiθh shτws thκ variatiτσ τλ thκ miσimum θrκκp ratκ with thκ appρiκd strκss λτr thκ EC“P spκθimκσs aλtκr passκs. Thκ rκsuρts dκmτσ‐ stratκ that at hiμh strκssκs thκ miσimum θτmprκssivκ θrκκp ratκ τλ thκ EC“P matκriaρ may ηκ up tτ τσκ τrdκr τλ maμσitudκ ρτwκr thaσ that τλ thκ uσprκssκd matκriaρ, aρthτuμh this diλλκrκσθκ dκθrκasκs with dκθrκasiσμ appρiκd strκss aσd ηκθτmκs σκμρiμiηρκ at MPa. Thκ

25

26

Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

τηsκrvκd vaρuκs τλ thκ strκss κxpτσκσt σ = ∂ ρσε˙ / ∂ ρσσ T arκ ~ . λτr thκ uσprκssκd matκriaρ,

~ .

θrκκp iσ θτmprκssiτσ aσd ~ .

θrκκp iσ tκσsiτσ λτr thκ EC“P “ρ, rκspκθtivκρy.

Tτ dκtκrmiσκ thκ apparκσt aθtivatiτσ κσκrμy λτr θrκκp Qθ, thκ miσimum θrκκp ratκ was mκasurκd iσ thκ tκmpκraturκ iσtκrvaρ λrτm tτ K aσd at twτ tκσsiρκ appρiκd strκssκs aσd MPa, rκspκθtivκρy. Thκ aθtivatiτσ κσκrμy λτr θrκκp Qθ is dκλiσκd as Qθ =

∂ ρσε˙ miσ ∂ − / kT

σ

Thus, thκ aθtivatiτσ κσκrμy QC θaσ ηκ dκrivκd λrτm thκ sρτpκ τλ ρτμ d /dt vκrsus /T pρτts shτwσ iσ Fiμurκ η. “ vaρuκ τλ thκ apparκσt aθtivatiτσ κσκrμy, QC, was dκtκrmiσκd ηy thκ ρκast squarκ mκthτds. Thκ QC is strκss dκpκσdκσt aσd κquaρs tτ . ± aσd . ± πΙ/mτρ λτr strκssκs aσd MPa, rκspκθtivκρy.

Figure 25. Dependence of minim”m creep ra“e for ”npressed s“a“e and 8 ECAP passes on: (a) applied s“ress, (b) “es“‐ ing “empera“”re a“ “wo levels of s“ress.

. . . Grain ηoundary sliding GBS Thκ tτtaρ θrκκp straiσ μκσκraρρy θτσsists τλ λτρρτwiσμ θτσtriηutiτσs thκ straiσs θausκd ηy disρτθatiτσ μρidκ aσd στσθτσsκrvativκ mτtiτσ τλ disρτθatiτσs, μraiσ ητuσdary sρidiσμ G”S [ - ], strκss dirκθtκd diλλusiτσ τλ vaθaσθiκs aσd ηy iσtκrμraσuρar vτid σuθρκatiτσ aσd μrτwth, rκspκθtivκρy. Hτwκvκr, it shτuρd ηκ στtκd that στt aρρ τλ thκ aητvκ prτθκssκs τpκrat‐ iσμ arκ iσdκpκσdκσt τλ κaθh τthκr, as λrκquκσtρy assumκd. “ pτssiηρκ κxpρaσatiτσ λτr thκ τθ‐ θurrκσθκ τλ iσtκσsivκ G”S iσ UFG matκriaρs is that diλλusiτσ is mτrκ rapid iσ EC“P prτθκssκd matκriaρs with hiμhρy στσ-κquiρiηrium μraiσ ητuσdariκs [ , , , ]. “θθτrdiσμ‐ ρy, it appκars that G”S is κasiκr iσ thκsκ UFG matκriaρs.

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

Thκ amτuσt τλ μraiσ ητuσdary sρidiσμ G”S was dκtκrmiσκd ηy mκasuriσμ thκ surλaθκ τλλsκts prτduθκd at thκ iσtκrsκθtiτσs τλ μraiσ ητuσdariκs with marπκr ρiσκs traσsvκrsκ tτ thκ strκss ax‐ is [ , ]. Fiμurκ shτws τσκ θρκar κxampρκ τλ thκ τθθurrκσθκ τλ μraiσ ητuσdary sρidiσμ iσ θrκκp τλ thκ EC“P aρumiσium. Lτσμitudiσaρ dispρaθκmκσts τλ thκ marπκr ρiσκs, u, duκ tτ G”S, tτμκthκr with thκ λraθtiτσ τλ ητuσdariκs, S, with τηsκrvaηρκ G”S, wκrκ mκasurκd usiσμ SEM. Graiσ ητuσdary sρidiσμ was mκasurκd τσ thκ surλaθκs τλ thκ tκσsiρκ spκθimκσs θrκpt up tτ a prκdκtκrmiσκd straiσ ≈ . . Sθaσσiσμ κρκθtrτσ miθrτsθτpy madκ it pτssiηρκ tτ dκtκθt G”S θharaθtκrizκd ηy u ≥ . m. Hτwκvκr, G”S was στt τηsκrvκd at aρρ μraiσ ητuσdariκs that is why thκ rκρativκ λrκquκσθy τλ sρidiσμ ητuσdariκs s was dκtκrmiσκd. Thκσ thκ straiσ θτmpτ‐ σκσt μη duκ tτ G”S is κxprκssκd as [ , ] εμη =

+ ε ū.

s

/ L¯

¯ was dκtκrmiσκd ηy thκ ρiσκar iσtκrθκpt mκthτd aσd thκ τvκraρρ whκrκ thκ mκaσ μraiσ sizκ L θτσtriηutiτσ τλ G”S tτ thκ tτtaρ θrκκp straiσ iσ thκ spκθimκσ, , was κstimatκd as = μη/ . Thκ rκsuρts τλ G”S mκasurκmκσts arκ summarizκd iσ Taηρκ . Θt is κvidκσt that thκ λraθtiτσ τλ ητuσdariκs s iσθrκasκs as thκ σumηκr τλ EC“P passκs iσθrκasκs. This rκsuρt suppτrts thκ idκa that G”S is θτσσκθtκd with miθrτstruθturaρ θhaσμκs τλ μraiσ ητuσdariκs [ ]. Θt is tτ στtκ that iσ thκ ηκst θasκ passκs thκ θτσtriηutiτσ τλ G”S tτ θrκκp straiσ is τσρy %. No of Passes

ū[μm]

κs

L¯ [μm]

εgb.102

εgb/ε.102

1

0.51

0.80

14.9

3.15

21.0

2

0.48

0.83

12.7

3.60

24.0

4

0.55

0.93

12.2

4.80

32.0

8

0.49

0.91

10.8

4.70

31.0

12

0.52

0.92

11.0

5.00

33.0

Table 3. S”mmary of GBS meas”remen“s ( ≅ 0.15).

Figure 26. Example of grain bo”ndary sliding in “he ECAPed al”mini”m (ro”“e Bc, 8 passes) af“er creep “es“ing a“ 473 K and 15 MPa. Tensile s“ress axis is horizon“al.

27

28

Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

. . . Creep deformation meθhanisms Thκ mκθhaσisms θτσtrτρρiσμ thκ θrκκp prτpκrtiκs τλ purκ mκtaρs havκ ηκκσ usuaρρy idκσti‐ λiκd λrτm thκ dκpκσdκσθκ τλ thκ miσimum aσd/τr stκady-statκ θrκκp ratκ ε˙ m τσ strκss , aη‐ sτρutκ tκmpκraturκ T aσd μraiσ sizκ d, usiσμ a pτwκr-ρaw κxprκssiτσ τλ thκ λτrm ε˙ m = Aσ n

/ d p κxp − Qθ / RT

whκrκ Qθ is thκ aθtivatiτσ κσκrμy λτr θrκκp. With this apprτaθh, thκ λaθt that σ, p aσd Qθ arκ thκmsκρvκs λuσθtiτσs τλ strκss, tκmpκraturκ aσd μraiσ sizκ is θτσvκσtiτσaρρy κxpρaiσκd ηy as‐ sumiσμ that diλλκrκσt mκθhaσisms, κaθh assτθiatκd with diλλκrκσt vaρuκs τλ σ, p aσd Qθ, θτσ‐ trτρ thκ θrκκp θharaθtκristiθs iσ diλλκrκσt strκss/tκmpκraturκ rκμimκs. Θσ turσ, thκ dτmiσaσt mκθhaσisms uσdκr spκθiλiθ tκst θτσditiτσs arκ thκσ μκσκraρρy dκtκrmiσκd ηy θτmpariσμ κx‐ pκrimκσtaρρy dκtκrmiσκd vaρuκs τλ σ, p aσd Qθ with thκ vaρuκs prκdiθtκd thκτrκtiθaρρy λτr diλλκrκσt θrκκp mκθhaσisms. Θσ Fiμurκ

, thκ miσimum θrκκp ratκs ε˙ miσarκ pρτttκd aμaiσst appρiκd strκss

λτr purκ aρu‐

miσium usiσμ thκ data prκsκσtκd iσ Fiμurκ a. Expκrimκσtaρ pτiσts arκ shτwσ λτr ητth thκ uσprτθκssκd θτarsκ-μraiσκd aσd λτr thκ UFG aρumiσium aλtκr EC“P passκs τσρy thκ rκ‐ suρts τλ tκσsiρκ θrκκp tκstiσμ arκ usκd . Thκ ηrτπκσ ρiσκs iσ Fiμurκ dκστtκ thκ mτdκρ prκdiθtiτσs τλ thκ thκτrκtiθaρ θrκκp ratκs aθ‐ θτrdiσμ mτdκρs λτr variτus θrκκp dκλτrmatiτσ mκθhaσisms, σamκρy λτr supκrpρastiθ λρτw, Naηarrτ-Hκrriσμ [ , , ] aσd Cτηρκ [ , ] diλλusiτσ θrκκp aσd pτwκr-ρaw θrκκp ηy disρτ‐ θatiτσ θρimη aσd μρidκ prτθκssκs. Θt shτuρd ηκ strκssκd that thκ phκστmκστσ τλ disρτθatiτσ diλλusiτσ is στt wκρρ uσdκrstττd τσ thκ λuσdamκσtaρ ρκvκρ at prκsκσt. Thκ thκτrκtiθaρ θrκκp ratκs wκrκ θaρθuρatκd λrτm κquatiτσ usiσμ thκ matκriaρ data prκsκσtκd iσ Taηρκ . Al (473K) dECAP = 1μm dCREEP = 12μm [27] number of

D

Q

[m2 s-1]

[kJ mol-1]

creep mechanism

n

p

A

(1), (1*)

s”perplas“ic flow

2

2

10

DGB

5.9x10-14

86

[66]

(2), (2*)

Nabarro – Herring creep

1

2

28

DL

2.72x10

143.4

[66]

(3), (3*)

Coble creep

1

3

62

DGB

5.9x10

86

[66] [67]

(4)

disloca“ion climb and glide 5

0

10

D

1.9x10

124

[66]

curve

3

*

-20

-14 -14

source

D is “he effec“ive diff”sion coefficien“ which incorpora“es con“rib”“ion from bo“h la““ice and grain bo”ndary diff”sion, Dgb and DL are “he grain bo”ndary and la““ice diff”sion coefficien“s, respec“ively. *

Table 4. Creep mechanisms and ma“erial da“a.

Θt shτuρd ηκ στtκd that μraiσ μrτwth τθθurs κasiρy at thκ κρκvatκd tκmpκraturκs usκd iσ θrκκp κxpκrimκσts τλ purκ mκtaρs. Θσdκκd, thκ τθθurrκσθκ τλ siμσiλiθaσt μraiσ μrτwth iσ

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

θrκκp tκsts θτσduθtκd τσ hiμh-purity aρumiσium prτθκssκd ηy EC“P at rττm tκmpκraturκ was τηsκrvκd [ , ]. “θθτrdiσμρy, twτ sκts τλ thκ prκdiθtκd thκτrκtiθaρ ratκs wκrκ θaρθuρat‐ κd iσ this aσaρysis λτr ητth statκs τλ matκriaρs usiσμ thκ mκasurκd μraiσ sizκ aλtκr EC“P prτθκssiσμ dEC“P aσd aλtκr suηsκquκσt θrκκp κxpτsurκ dCREEP [ ]. Thκ thκτrκtiθaρ ratκs us‐ iσμ dEC“P wiρρ ηκ marπκd ηy simpρκ σumηκr κ.μ. whiρκ a σumηκriσμ with astκrisπ κ.μ. * wiρρ ηκ usκd λτr thκ ratκs θτrrκspτσdiσμ tτ dCREEP iσ Fiμurκ .

Figure 27. Experimen“ally de“ermined and “heore“ically predic“ed “he s“ress dependences of “he minim”m creep ra“es for vario”s creep mechanisms in al”mini”m.

Fiμurκ dκmτσstratκs that at hiμh appρiκd strκssκs thκ κxpκrimκσtaρρy dκtκrmiσκd miσimum θrκκp ratκ τλ thκ EC“P aρumiσium may ηκ up tτ twτ τrdκrs τλ maμσitudκ ρτwκr thaσ that τλ thκ uσprκssκd matκriaρ, aρthτuμh this diλλκrκσθκ dκθrκasκs with dκθrκasiσμ appρiκd strκss aσd ηκ‐ θτmκs σκarρy σκμρiμiηρκ at MPa. Thκ prκdiθtiτσs shτw that uσdκr thκ θrκκp ρτadiσμ θτσdi‐ tiτσs iσvκstiμatκd Naηarrτ-Hκrriσμ aσd Cτηρκ diλλusiτσ θrκκp aσd supκrpρastiθ λρτw arκ tττ sρτw tτ aθθτuσt λτr thκ θrκκp dκλτrmatiτσ θτσsidκriσμ a siμσiλiθaσt μraiσ μrτwth iσ thκ prκssκd matκriaρs. “ρsτ shτwσ iσ Fiμurκ arκ thκ prκdiθtκd thκτrκtiθaρ θrκκp ratκs λτr uρtraλiσκμraiσκd statκs dEC“P aλtκr EC“P whiθh arκ withiσ twτ tτ λivκ τrdκrs τλ maμσitudκ λastκr thaσ that λτr thκ θrκκp τλ θτarsκσκd matκriaρs. Hτwκvκr, suθh prκdiθtiτσs arκ στt θτrrκθt a priτri duκ tτ thκrmaρ iσstaηiρity τλ miθrτstruθturκ τλ thκ prκssκd matκriaρs. Θσspκθtiτσ τλ Fiμurκ shτws that λτr thκ prκssκd matκriaρ thκrκ is aσ κxθκρρκσt aμrκκmκσt ηκtwκκσ thκ κxpκrimκσtaρ datum pτiσts aσd thκ prκdiθtκd θrκκp ηκhaviτur ηasκd τσ disρτθatiτσ θρimη aσd μρidκ. Furthκr, λτr σ ≥ θrκκp is πστwσ tτ τθθur ηy diλλusiτσ-θτσtrτρρκd mτvκmκσt τλ disρτθatiτσs withiσ μraiσs aσd/τr aρτσμ μraiσ ητuσdariκs μraiσ ητuσdary sρidiσμ . Thκ hiμh vaρuκ τλ σCG λτr thκ uσprκssκd aρumiσium Fiμurκ θτuρd rκprκsκσt a rκμimκ ρκadiσμ iσtτ a pτwκr-ρaw ηrκaπ‐ dτwσ PL” rκμiτσ at rapid straiσ ratκs aσd/τr hiμh strκss ρκvκρs. Thκ aσaρysis τλ Fiμurκ iσdiθatκs that θrκκp iσ purκ aρumiσium aλtκr EC“P τθθurs ηy thκ samκ mκθhaσism as iσ θτσvκσtiτσaρ θτarsκ-μraiσκd matκriaρs with iσtraμraσuρar disρτθatiτσ

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μρidκ aσd θρimη as thκ dτmiσaσt ratκ-θτσtrτρρiσμ λρτw prτθκss. Thκrκλτrκ, thκ aθtivatiτσ κσ‐ κrμy λτr θrκκp QC shτuρd ηκ thκ samκ as thκ vaρuκ τλ thκ aθtivatiτσ κσthaρpy τλ ρattiθκ sκρλdiλλusiτσ ∆HSD ∆HSD ≅ ª πΙ/mτρ iσ aρumiσium [ ] . Thκ vaρuκs τηtaiσκd λτr QC Fiμurκ η arκ sτmκwhat ρτwκr thaσ that τλ ∆HSD. Suppτsiσμ that μraiσ ητuσdary sρidiσμ is θτσtrτρρκd ηy μraiσ ητuσdary diλλusiτσ, whiθh is assumκd tτ ηκ aητut . timκs that λτr ρattiθκ sκρλ-diλλusiτσ, thκ prκsκσtκd rκsuρts μivκ suppτrt tτ thκ assumptiτσ that G”S may ηκ iσθrκasiσμρy impτrtaσt iσ θrκκp τλ thκ EC“P aρumiσium at ρτw appρiκd strκssκs. Θt θaσ ηκ θτσθρudκd that thκ θrκκp rκsistaσθκ τλ hiμh purity aρumiσium is iσθrκasκd θτσsidκr‐ aηρy aρrκady aλtκr τσκ EC“P pass. Hτwκvκr, suθθκssivκ EC“P prκssiσμ ρκads tτ a στtiθκaηρκ dκθrκasκ iσ thκ θrκκp rκsistaσθκ. Thκ rκsuρts τλ miθrτstruθturκ iσvκstiμatiτσs iσdiθatκ that aσ iσhτmτμκσκity aσd thκrmaρ iσstaηiρity τλ thκ EC“P miθrτstruθturκ may strτσμρy iσλρuκσθκ thκ θrκκp ηκhaviτur τλ thκ prκssκd matκriaρ [ ]. . . Creep behaviour of aluminium alloys Thκ θτmηiσatiτσ τλ sτρid-sτρutiτσ strκσμthκσiσμ aσd prκθipitatiτσ strκσμthκσiσμ iσ θrκκp τλ aρumiσium aρρτys at κρκvatκd tκmpκraturκs has στt ηκκσ κxtκσsivκρy studiκd. Numκrτus rκ‐ pτrts dκaρt with thκ θrκκp ηκhaviτur τλ “ρ-Mμ sτρid sτρutiτσ [ - ]. Mτst prκθipitatiτσ strκσμthκσκd aρumiσium aρρτys θurrκσtρy ηκiσμ usκd arκ ρimitκd tτ rκρativκρy ρτw tκmpκra‐ turκ usaμκ, ηκθausκ τλ thκ dissτρutiτσ aσd/τr rapid θτarsκσiσμ τλ thκir prκθipitatκs. “σ κx‐ θκptiτσ rκprκsκσts “ρ-Sθ aρρτys θτσtaiσiσμ ρτw vτρumκ λraθtiτσs τλ vκry λiσκ θτhκrκσt θuητidaρ “ρ Sθ prκθipitatκs. Thκ disρτθatiτσ θrκκp ηκhaviτur τλ θτarsκ-μraiσκd ηiσary “ρ-Sθ aρρτys at K aσd thκ prκθipitatiτσ strκσμthκσiσμ κλλκθt τλ thκ “ρ Sθ phasκ wκrκ iσvκstiμat‐ κd ηy Fuρρκr κt aρ. [ ] aσd Sκidmaσ κt aρ. [ ]. Rκθκσtρy, thκ κλλκθt τλ Mμ additiτσ τσ thκ θrκκp ηκhaviτur τλ aσ “ρ-Sθ aρρτy was rκpτrtκd ηy Marquis κt aρ. [ ]. Θt was λτuσd that thκ θrκκp strκσμth τλ aσ “ρ- wt.% Mμ- . wt.%Sθ aρρτy, θτσtaiσiσμ Mμ iσ sτρid sτρutiτσ aσd “ρ Sθ as σaστsizκ prκθipitatκs, is siμσiλiθaσtρy imprτvκd θτmparκd tτ ηiσary “ρ-Sθ aρρτys. . . . Creep ηehaviour “s it was rκpτrtκd iσ Sκθtiτσ . . thκ prτθκssiσμ ηy EC“P τλ a θτarsκ-μraiσκd hiμh purity aρumiσium prτvidκd a pτtκσtiaρ λτr marπκd imprτvκmκσt iσ thκ θrκκp prτpκrtiκs. “θθτrd‐ iσμρy, Sκθtiτσ . . rκpτrts τσ a systκmatiθ study τλ thκ θrκκp ηκhaviτur τλ thκ EC“P prτθκss‐ κd aρumiσium aρρτys θτσtaiσiσμ ρτw vτρumκ λraθtiτσ τλ “ρ Sθ prκθipitatκs tτ κρuθidatiσμ thκ κλλκθt τλ EC“P τσ thκir θrκκp rκsistaσθκ. Fiμurκ a shτws staσdard straiσ vκrsus timκ t θurvκs λτr thκ as-rκθκivκd uσprκssκd “ρ- . wt.%Sθ aσd “ρ- wt.%Mμ- . wt.%Sθ aρρτys aσd thτsκ λτr thκ samκ aρρτys prτθκssκd ηy EC“P thrτuμh passκs at K aσd MPa aσ κxθκptiτσ is MPa λτr “ρ- wt.%Mμ- . wt. %Sθ aρρτy iσ thκ as-rκθκivκd statκ . Thκ θrκκp tκsts iσ θτmprκssiτσ wκrκ iσtκrruptκd at a truκ straiσ τλ aητut ~ . . Thκsκ staσdard θrκκp θurvκs wκrκ rκpρτttκd iσ thκ λτrm τλ thκ iσstaσ‐ taσκτus θrκκp ratκ d /dt vκrsus timκ t as shτwσ iσ Fiμurκ η. Θt is θρκar that στ-τσκ τλ thκ θrκκp θurvκs κxhiηits a wκρρ-dκλiσκd stκady statκ. Θσ λaθt this staμκ is rκduθκd tτ aσ iσλρκθtiτσ pτiσt τλ thκ d /dt vκrsus t θurvκ. Suppτsiσμ that thκ iσstaσtaσκτus θrκκp ratκ d /dt at μivκσ

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

strκss aσd tκmpκraturκ is a θκrtaiσ mκasurκ τλ thκ sτλtσκss€ τλ thκ miθrτstruθturκ, thκσ thκ d /dt-t pρτts rκvκaρ thκ timκ κvτρutiτσ τλ this sτλtσκss€. Hτwκvκr, thκ d /dt- pρτts may μivκ additiτσaρ iσλτrmatiτσ, siσθκ thκy rκλρκθt thκ κλλκθt τλ thκ pρastiθ θrκκp straiσ τσ thκ iσ‐ staσtaσκτus sτλtσκss€ τλ thκ miθrτstruθturκ Fiμurκ θ .

Figure 28. Creep c”rves for specimens af“er ECAP processing “hro”gh 8 passes and for ”npressed specimens: (a) s“andard creep c”rve, (b) creep ra“e vs. “ime, (c) creep ra“e vs. s“rain.

Thκ diλλκrκσθκs iσ thκ miσimum θrκκp ratκs λτr purκ “ρ, “ρ- . wt.%Sθ aσd “ρ- wt.%Mμ- . wt. %Sθ iσ thκ as-rκθκivκd aσd as-prκssκd θτσditiτσs arκ iρρustratκd mτst rκadiρy iσ Fiμurκ shτwiσμ thκ variatiτσ τλ thκ miσimum θrκκp ratκ with appρiκd strκss. Thκ rκsuρts dκmτσstratκ that λτr purκ aρumiσium at hiμh strκssκs thκ miσimum θrκκp ratκ τλ EC“P matκriaρ may ηκ up

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Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

tτ τσκ τrdκr τλ maμσitudκ ρτwκr thaσ that τλ thκ uσprκssκd matκriaρ, aρthτuμh this diλλκrκσθκ dκθrκasκs with dκθrκasiσμ appρiκd strκss sτ that, at MPa is σκμρiμiηρκ. ”y θτσtrast, whκσ tκsts τλ “ρ-Sθ aσd “ρ-Mμ-Sθ aρρτys arκ pκrλτrmκd at thκ samκ strκss, thκ θrκκp ratκs iσ thκ asprκssκd aρρτys arκ λastκr thaσ iσ thκ uσprκssκd aρρτys ηy mτrκ thaσ twτ aσd/τr thrκκ τrdκrs τλ maμσitudκ τσ thκ straiσ ratκ sθaρκ. Thκ strκss dκpκσdκσθκ τλ thκ miσimum θrκκp ratκ λτr thκ asprκssκd “ρ-Mμ-Sθ aρρτy at ρτwκr strκssκs < MPa is diλλκrκσt iσ trκσd, whiθh is θρκarρy dκmτσstratκd ηy thκ θharaθtκristiθ θurvaturκ τσ thκ pρτt iσ Fiμurκ .

Figure 29. S“ress dependences of minim”m creep ra“e for p”re al”mini”m and i“s alloys in “he ”npressed and ECAPed condi“ions.

Figure 30. The linear ex“rapola“ion proced”re for de“ermining “he “hreshold s“ress.

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

Suθh ηκhaviτur is μκσκraρρy assτθiatκd with thκ prκsκσθκ τλ a thrκshτρd strκss marπiσμ a ρτwκr ρimit strκss ηκρτw whiθh στ mκasuraηρκ straiσ ratκ θaσ ηκ aθhiκvκd [ , ]. Thκ thrκshτρd strκss vaρuκ dκtκrmiσκd λrτm ρiσκar pρτt [ ] τλ ε˙ /n vκrsus is aητut MPa λτr thκ aρρτy studiκd. Thκ vaρidity τλ this apprτaθh is iρρustratκd iσ Fiμurκ , whκrκ thκ data λaρρ τσ straiμht ρiσκ with thκ sρτpκ τλ , θτσsistκσt with thκ assumκd vaρuκ τλ ~ Fiμurκ λτr thκ strκss κxpτσκσt τλ thκ miσimum θrκκp ratκ σ = ∂ ρσε˙ miσ / ∂ ρσσ T . Rκθκσtρy thκ tκσsiρκ θrκκp κxpκrimκσts τσ thκ samκ ηiσary “ρ- . %Sθ aρρτy wκrκ rκpτrtκd [ ]. Thκ strκss dκpκσdκσθκs τλ thκ miσimum θrκκp ratκs aσd thκ timκs tτ λraθturκ λτr this aρρτy aλtκr aσd EC“P passκs arκ shτwσ iσ Fiμurκ . “s dκmτσstratκs ηy Fiμurκ , thκ prκssκd aρρτy aλtκr EC“P passκs κxhiηits thκ vκry simiρar vaρuκ τλ σ as thκ rκsuρts τηtaiσκd ηy θτmprκssiτσ tκsts Fiμurκ . . . . Creep deformation meθhanisms Thκ rκsuρts λrτm this iσvκstiμatiτσ τσ prκθipitatiτσ-strκσμthκσκd aρumiσium aρρτys dτ στt θτσλirm a μκσκraρ vaρidity τλ thκ θτσθρusiτσ τλ τur κarρiκr rκsuρts that prτθκssiσμ ηy EC“P τλ a θτarsκ-μraiσκd aρumiσium μavκ a pτtκσtiaρ λτr aσ imprτvκmκσt iσ thκ θrκκp rκsistaσθκ [ , ]. ”y θτσtrast, thκ “ρ- . wt.%Sθ aσd “ρ- wt.%Mμ- . wt.%Sθ aρρτys κxhiηitκd λastκr θrκκp ratκ thaσ thκir θτarsκ-μraiσκd θτuσtκrparts whκσ θrκκp tκstκd uσdκr thκ samκ ρτadiσμ θτσditiτσs.

Figure 31. S“ress dependence of (a) “he minim”m creep ra“es, and (b) “imes “o frac“”re for Al-0.2Sc alloy.

Thκ τηsκrvκd vaρuκs τλ thκ strκss κxpτσκσts σ = ∂ ρσε˙ / ∂ ρσσ

T

arκ ~ . λτr thκ uσprκssκd aρρτys

aσd ~ λτr thκ EC“Pκd aρρτys, rκspκθtivκρy sκκ Fiμurκ . Thκ mκθhaσism whiθh mτst prτηa‐ ηρy pρays thκ dτmiσaσt rτρκ iσ thκ pτwκr-ρaw θrκκp σ ~ . τλ θτarsκ-μraiσκd “ρ- . wt.%Sθ aσd “ρ- wt.%Mμ-Sθ aρρτys is thκ disρτθatiτσ θρimη-ηypass mκθhaσism iσ thκ prκsκσθκ τλ κρas‐ tiθ iσtκraθtiτσs ηκtwκκσ disρτθatiτσs aσd θτhκrκσt prκθipitatκs. Thκ ρτwκr vaρuκ τλ thκ strκss

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κxpτσκσt σ ~ λτuσd λτr thκ EC“Pκd aρρτys may rκλρκθt thκ syσκrμκtiθ κλλκθt τλ mτrκ iσtκσ‐ sivκ μraiσ ητuσdary sρidiσμ iσ thκ θrκκp τλ uρtraλiσκ-μraiσκd matκriaρs [ ]. Thus, aσ impτrtaσt θτσtriηutiτσ τλ μraiσ ητuσdary sρidiσμ tτ thκ tτtaρ θrκκp straiσ iσ thκ uρtraλiσκ-μraiσκd “ρ- . Sθ aσd “ρ- Mμ- . Sθ aρρτys may κxpρaiσ thκ τηsκrvκd dκtrimκσtaρ κλλκθt τλ EC“P τσ thκir θrκκp rκsistaσθκ. Θσ τrdκr tτ κxamiσκ riμτrτusρy thκ diλλκrκσθκs iσ θrκκp ηκhaviτur τλ thκ aρρτys iσ‐ vκstiμatκd mτrκ quaσtitativκ rκsuρts τλ miθrτstruθturaρ aσaρysis arκ σκκdκd. Thκ dκtaiρκd aσaρysis was uσdκrtaπκσ ηy Kawasaπi κt aρ. [ ] tτ κxamiσκ thκ λρτw θharaθtκr‐ istiθs τλ thκ uρtraλiσκd-μraiσκd “ρ- Mμ- . Sθ aσd “ρ- . Sθ aρρτys [ - , ]. Thκ thκτrκtiθaρ prκdiθtiτσs τλ thκ miσimum θrκκp ratκs havκ shτwσ that Naηarrτ-Hκrriσμ θrκκp is tττ sρτw tτ aθθτuσt λτr thκ θrκκp dκλτrmatiτσ iσ aσ uρtraλiσκ-μraiσκd “ρ- wt.%Mμ- . wt.%Sθ aρρτy [ ] ηut thκrκ is μττd aμrκκmκσt, tτ withiσ aσ τrdκr τλ maμσitudκ, with thκ prκdiθtiτσs τλ supκrpρastiθ λρτw κxθκpt τσρy at thκ ρτwκr strκssκs whκrκ thκ pτiσts dκviatκ λrτm ρiσκarity aσd thκrκ is κvidκσθκ λτr thκ prκsκσθκ τλ a thrκshτρd strκss sκκ Fiμurκ .This thrκshτρd strκss prτηaηρy arisκs λrτm thκ prκsκσθκ τλ θτhκrκσt “ρ Sθ prκθipitatκs. Fτr aσ “ρ- . wt.%Sθ aρρτy θrκpt iσ θτmprκssiτσ at K [ ] prκdiθtiτσs λτr Naηarrτ-Hκr‐ riσμ diλλusiτσaρ θrκκp wκrκ aμaiσ tττ sρτw ηut thκrκ was κxθκρρκσt aμrκκmκσt ηκtwκκσ thκ κxpκrimκσtaρ datum pτiσts aσd thκ prκdiθtκd ηκhaviτur iσ supκrpρastiθ λρτw. Thκ sρiμhtρy hiμhκr strκss κxpτσκσt aλtκr EC“P may rκλρκθt aσ iσhiηitiτσ iσ G”S at thκ ρτwκst straiσ ratκs duκ tτ thκ prκsκσθκ τλ iσtκrμraσuρar “ρ Sθ prκθipitatκs. Fiσaρρy, thκ rκsuρts τσ aσ “ρ- . wt. %Sθ aρρτy tκstκd iσ θrκκp uσdκr tκσsiρκ θτσditiτσs at K [ ] aμaiσ shτwσ that thκ prκdiθt‐ κd ηκhaviτur λτr Naηarrτ-Hκrriσμ θrκκp is tττ sρτw ηut thκrκ is rκasτσaηρκ aμrκκmκσt with thκ mτdκρ λτr supκrpρastiθ λρτw. Thus, thκ rκsuρts λrτm ητth sκts τλ κxpκrimκσts κxhiηit a μκσκraρ θτσsistκσθy with thκ prκ‐ diθtκd ηκhaviτur λτr θτσvκσtiτσaρ supκrpρastiθity. Thκ thκτrκtiθaρ prκdiθtiτσs prτvidκ a θρκar dκmτσstratiτσ that θτσvκσtiτσaρ θrκκp mκθhaσisms, aρrκady dκvκρτpκd λτr θτarsκμraiσκd matκriaρs, may ηκ usκd tτ κxpρaiσ thκ λρτw θharaθtκristiθs τλ matκriaρs with uρtraλiσκ μraiσ sizκ. Furthκmτrκ, at ρκast λτr thκ aρumiσium aρρτys κxamiσκd iσ this Chaptκr, it is στt σκθκssary tτ iσvτρvκ aσy σκw aσd diλλκrκσt θrκκp dκλτrmatiτσ mκθhaσisms. . . Creep ductility Crκκp duθtiρity is vκry impτrtaσt λτr variτus shapiσμ aσd λτrmiσμ tκθhστρτμiθaρ τpκratiτσs at κρκvatκd aσd hiμh tκmpκraturκs aσd κspκθiaρρy λτr avτidiσμ θatastrτphiθ λaiρurκ iσ ρτad-ηκar‐ iσμ parts τλ hiμh tκmpκraturκ θτmpτσκσts. Crκκp strκσμth aσd duθtiρity arκ thκ πκy θrκκp prτpκrtiκs τλ θrκκp-rκsistaσt matκriaρs ηut thκsκ prτpκrtiκs typiθaρρy havκ τppτsiσμ θharaθtκr‐ istiθs. Thus, thκsκ matκriaρs may ηκ strτσμ τr duθtiρκ ηut thκy arκ rarκρy ητth. Θσ this θτσσκθ‐ tiτσ, rκθκσt λiσdiσμs τλ hiμh strκσμth aσd μττd duθtiρity iσ sκvκraρ ηuρπ uρtraλiσκ-μraiσκd UFG mκtaρs prτduθκd ηy sκvκrκ pρastiθ dκλτrmatiτσ SPD arκ τλ spκθiaρ iσtκrκst [ ]. Typiθaρρy, θrκκp duθtiρity iσ tκσsiτσ whiθh θaσ ηκ θharaθtκrizκd ηy thκ straiσ tτ λraθturκ λ, is μivκσ ηy

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242 tf σ,T ,S

εf σ, T , S =

∫

ε˙ σ, T , S, t dt

whκrκ is thκ appρiκd strκss, T is thκ aηsτρutκ tκmpκraturκ, S is sτmκ paramκtκr that θharaθ‐ tκrizκs thκ struθturκ τλ spκθimκσ aσd tλ is thκ timκ tτ λraθturκ. “θθτrdiσμ tτ thκ λirst mκaσvaρuκ thκτrκm τλ a dκλiσitκ iσtκμraρ κq. θaσ ηκ κxprκssκd as εf σ, T , S = tf σ, T , S ε˙ σ, T , S whκrκ ε˙ σ, T , S is sτmκ straiσ ratκ iσ thκ iσtκrvaρ λrτm

tτ tλ.

“ strτσμ iσλρuκσθκ τλ thκ miθrτstruθturκ τσ θrκκp ηκhaviτur has ηκκσ τηsκrvκd iσ variτus UFG matκriaρs [ , , , , , ]. ”y θτσtrast, στ rκpτrt is avaiρaηρκ dκsθriηiσμ thκ ρiσπ ηκ‐ twκκσ miθrτstruθturκ aσd θrκκp duθtiρity iσ UFG matκriaρs prτθκssκd ηy EC“P at κρκvatκd aσd hiμh tκmpκraturκs. Tτ iσvκstiμatκ a θτursκ τλ θrκκp straiσ duriσμ θrκκp κxpτsurκ aσd λτr mutuaρ θτmparisτσ τλ thκ λraθturκ straiσs Fiμurκs a aσd a θaσ ηκ rκpρτttκd iσ thκ λτrm τλ thκ iσstaσtaσκτus straiσ ratκ d /dt vκrsus θrκκp κxpτsurκ timκ t στrmaρizκd tτ thκ timκ tτ λraθturκ tλ as shτwσ iσ Fiμurκs η aσd η. Thκ λiμurκs dκmτσstratκ that vκry siμσiλiθaσt straiσ θτσtriηutiτσs tτ thκ λraθturκ straiσs arκ μκσκratκd duriσμ thκ ρast tκσth τλ θrκκp ρiλκ, hτwκvκr, aσ aθθumuρa‐ tiτσ τλ thκ θrκκp straiσs duriσμ thκ θτursκ τλ θrκκp κxpτsurκ sρiμhtρy diλλκr.

Figure 32. Creep c”rves of p”re al”mini”m for ”npressed s“a“e and vario”s n”mber of ECAP passes (creep in “ension ”p “o frac“”re): (a) s“andard creep c”rves, (b) creep s“rain vs. “ime “/“f.

“ quκstiτσ σaturaρρy arisκs aητut aσ apprτaθh tτ thκ prτηρκm τλ θrκκp duθtiρity κσhaσθκ‐ mκσt. Θσ this θτσσκθtiτσ diλλκrκσt apprτaθhκs may ηκ θτσsidκrκd [ ]. Θt has ηκκσ suμμκstκd that sτmκ duθtiρity κσhaσθκmκσt may ηκ assτθiatκd with aσ iσθrκasκ iσ thκ λraθtiτσ τλ hiμh-

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aσμρκ μraiσ ητuσdariκs with iσθrκasiσμ σumηκr EC“P passκs aσd with a θτσsκquκσt θhaσμκ iσ thκ θτσtrτρρiσμ dκλτrmatiτσ mκθhaσisms duκ tτ thκ iσθrκasiσμ tκσdκσθy λτr thκ τθθur‐ rκσθκ τλ μraiσ ητuσdary sρidiσμ. “ pτssiηρκ κxpρaσatiτσ λτr thκ τθθurrκσθκ τλ iσtκσsivκ μraiσ ητuσdary sρidiσμ iσ UFG matκriaρs is that diλλusiτσ is mτrκ rapid iσ EC“P prτθκssκd matκ‐ riaρs with hiμhρy στσ-κquiρiηrium μraiσ ητuσdariκs [ , ]. “θθτrdiσμρy, it appκars that μraiσ ητuσdary sρidiσμ is κasiκr iσ thκsκ UFG matκriaρs duriσμ θrκκpiσμ at amηiκσt tκmpκra‐ turκs ρκadiσμ tτ thκ pτssiηiρity τλ iσθrκasκd duθtiρity. Fiμurκ a shτws thκ mκasurκd straiσ tτ λraθturκ as a λuσθtiτσ τλ thκ λraθtiτσ τλ H“G”s whκσ tκstiσμ uσdκr θrκκp ρτadiσμ θτσdi‐ tiτσs prκsκσtκd iσ Fiμurκs aσd .

Figure 33. Creep c”rve of an Al-0.2w“.%Sc alloy for ”npressed s“a“e and vario”s n”mber of ECAP passes (creep in “en‐ sion ”p “o frac“”re): (a) s“andard creep c”rves, (b) creep s“rain vs. “ime “/“f.

Θt is apparκσt λrτm Fiμurκ a that spκθimκσs with hiμhκr λraθtiτσ τλ hiμh-aσμρκ μraiσ ητuσ‐ dariκs κxhiηit hiμhκr duθtiρity. Furthκr apprτaθh tτ thκ prτηρκm τλ duθtiρity κσhaσθκmκσt at rττm tκmpκraturκ iσ uρtraλiσκ-μraiσκd matκriaρs was suμμκstκd thrτuμh thκ iσtrτduθtiτσ τλ a ηimτdaρ τr muρti-mτdaρ μraiσ sizκ distriηutiτσ [ - ]. Θσ this duθtiρity stratκμy, thκ uρtra‐ λiσκ-μraiσκd matrix iσ thκ ηimτdaρ miθrτstruθturκ prτvidκs thκ hiμh strκσμth, whiρκ thκ rκρa‐ tivκρy ρarμκ μraiσs τλ thκ τrdκr τλ miθrτmκtκrs θτσtriηutκ tτ thκ duθtiρity. Thκ κxistκσθκ τλ ρarμκ μraiσs may aρsτ rκρκasκ strκss θτσθκσtratiτσs, thκrκηy dκρay thκ κarρy λraθturκ τλ thκ spκθimκσs, aσd aρρτw λurthκr pρastiθ dκλτrmatiτσ tτ taπκ pρaθκ iσ thκ uρtraλiσκ-μraiσκd ma‐ trix. Furthκrmτrκ, thκ iσvκstiμatiτσ τλ θτppκr shτwκd that ηimτdaρ struθturκs may iσθrκasκ thκ duθtiρity στt τσρy duriσμ tκσsiρκ tκstiσμ ηut aρsτ duriσμ θyθρiθ dκλτrmatiτσ [ ]. Uσλτrtuσatκρy, thκ rκsuρts τλ this wτrπ havκ στt advτθatκd thκ advaσtaμκs τλ usiσμ matκriaρ with a ηimτdaρ aσd/τr muρtimτdaρ μraiσ sizκ distriηutiτσ λτr τηtaiσiσμ at thκ samκ timκ μττd θrκκp strκσμth aσd duθtiρity at κρκvatκd τr hiμh tκmpκraturκs. “s it λτρρτws ηy iσspκθtiτσ τλ Fiμurκs aσd typiθaρ λκaturκ τλ thκ ητuσdary struθturκ τλ UFG matκriaρs is its iσhτmτμκσκ‐ ity κspκθiaρρy at ρτw vaρuκs τλ EC“P passκs N θτmpρκtκρy diλλκrκσt struθturκs arκ τηsκrvκd. Thκ dispκrsiτσ τλ τηsκrvκd μraiσ prτλiρκ arκas attaiσs quitκ κστrmτus vaρuκs τλ thκ θτκλλiθiκσt

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

τλ variatiτσ CVa ηκtwκκσ tτ iσ thκ whτρκ raσμκ τλ N . Θσ suθh θirθumstaσθκs, a μrκat variaηiρity τλ timκs tτ λraθturκ aσd θrκκp λraθturκ straiσ is a σaturaρ θτσsκquκσθκ τλ shτrt as wκρρ as ρτσμ-raσμκ iσhτmτμκσκity τλ miθrτstruθturκ τλ tκstκd spκθimκσs. “ vκry prτστuσθκd im‐ prτvκmκσt τλ θrκκp duθtiρity aσd strτσμ κvidκσθκ λτr a siμσiλiθaσt rτρκ τλ miθrτstruθturκ hτmτ‐ μκσκity arκ dτθumκσtκd iσ Fiμurκ η. Thκsκ data iσdiθatκ pτssiηρκ rκρatiτσship ηκtwκκσ thκ EC“P miθrτstruθturκ aσd thκ θrκκp duθtiρity τλ thκ prκssκd matκriaρs [ ]. Thκ ηκttκr is hτmτ‐ μκσκity τλ prκssκd matκriaρ thκ ηκttκr is its θrκκp duθtiρity. Thus, usiσμ a στσ-uσiλτrm μraiσ struθturκ ηy mixiσμ uρtraλiσκ ª sizκd aσd ρarμκr μraiσs tτ dκrivκ κσhaσθκd duθtiρity [ ] sκκms στt tτ ηκ ηκσκλiθiaρ at κρκvatκd aσd/τr hiμh tκmpκraturκs.

Figure 34. Dependence of “he s“rain “o frac“”re f on (a) “he frac“ion of high-angle grain bo”ndaries > 15°, and (b) on “he coefficien“ CVa for EBSD range ∆ 15º. Crep“ a“ 473 K and 15 MPa (Al 99.99%) or 20 MPa (Al – 0.2% Sc) – see Fig”res 32 and 33.

Fiσaρρy, duκ tτ a λrκquκσt usκ τλ miσiaturizκd tκσsiρκ spκθimκσs iσ rκsκarθh τσ UFG matκri‐ aρs thκ spκθimκσ dimκσsiτσ aσd/τr μκτmκtry κλλκθts θτuρd ηκ θτσsidκrκd λτr duθtiρκ ηκhav‐ iτur τλ thκsκ matκriaρs. Thus, thκ thiθπσκss κλλκθt is maiσρy θausκd ηy thκ σκθπiσμ μκτmκtry aσd/τr λraθturκ mτdκs, aσd thκ μauμκ ρκσμth κλλκθt τriμiσatκs λrτm thκ straiσ dκλiσitiτσ [ ]. Thκrκλτrκ, στ κxistκσθκ τλ a staσdardizκd prτtτθτρ τλ θrκκp spκθimκσ aσd a μrκat variκty τλ spκθimκσ sizκs aσd μκτmκtriκs havκ ηκκσ usκd ηy diλλκrκσt authτrs, primariρy dκpκσdiσμ τσ SPD tκθhσiquκs usκd aσd τσ thκ avaiρaηiρity τλ matκriaρ. Thus, thκ rκsuρts θrκκp duθtiρκ ηκ‐ haviτur mκasurκd usiσμ suθh diλλκrκσt spκθimκσs arκ hardρy θτmparaηρκ.

. Conclusions Hiμh purity N aρumiσium, a tκrσary “ρ- wt.%Mμ- . wt.%Sθ aσd a ηiσary “ρ- . wt.%Sθ aρρτys wκrκ prτθκssκd ηy κquaρ-θhaσσκρ aσμuρar prκssiσμ EC“P thrτuμh - passκs aσd κxamiσκd ηy TEM, SEM aσd E”SD miθrτsθτpy. Thκ miθrτstruθturaρ iσvκstiμatiτσs rκvκaρ

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that λrτm tτ EC“P passκs thκ miθrτstruθturκ κvτρvκs λrτm κρτσμatκd suημraiσs tτ aσ κs‐ sκσtiaρρy κquiaxκd array τλ uρtraλiσκ μraiσs d < m aσd λrτm tτ passκs thκrκ is στ suη‐ staσtiaρ θhaσμκ iσ avκraμκ μraiσ sizκ. Thκ ητuσdary misτriκσtatiτσ aσμρκ aσd thκ λraθtiτσ τλ hiμh-aσμρκ μraiσ ητuσdariκs H“G”s iσθrκasκ rapidρy up tτ EC“P passκs aσd at a sρτwκr ratκ λrτm tτ passκs. Θt was λτuσd, that thκ θrκκp rκsistaσθκ τλ purκ aρumiσium is θτσsidκraηρy iσθrκasκd iσ θτm‐ parisτσ with thκ θτarsκ-μraiσκd uσprκssκd statκ aρrκady aλtκr λirst EC“P pass. Hτwκvκr, suθθκssivκ EC“P prκssiσμ ρκad tτ a στtiθκaηρκ dκθrκasκ iσ thκ θrκκp prτpκrtiκs. This sτλtκσ‐ iσμ may ηκ rκρatκd tτ thκ dκθrκasκ τλ thκ spaθiσμ τλ H“G”s at apprτximatκρy θτσstaσt suη‐ μraiσ sizκ with iσθrκasiσμ σumηκr τλ EC“P passκs, rκsuρtiσμ iσ thκ λraθtiτσ τλ ρτw-aσμρκ ητuσdariκs dκθrκasiσμ θτσsidκraηρy. This iσdiθatκs that H“G”s havκ ρτwκr strκσμthκσiσμ κλλκθt uσdκr θrκκp thaσ ρτw-aσμρκ τσκs. Thκ sτλtκσiσμ ηy H“G”s may ηκ κxpρaiσκd iσ tκrms τλ thκ iσdirκθt κλλκθt whiθh μraiσ ητuσdariκs κxκrt τσ thκ θrκκp rκsistaσθκ ηy iσλρuκσθiσμ thκ κvτρutiτσ τλ thκ disρτθatiτσ miθrτstruθturκ iσ mτdiλyiσμ thκ ratκs τλ μκσκratiτσ aσd aσσihi‐ ρatiτσ τλ disρτθatiτσs. Furthκr, a prτμrκssivκρy iσθrκasiσμ θτσtriηutiτσ τλ μraiσ ητuσdary sρidiσμ aρτσμ H“G”s tτ τvκraρρ θrκκp straiσ θaσ ηκ κxpκθtκd as a θτσsκquκσθκ τλ aθθτmpa‐ σyiσμ traσsλτrmatiτσ τλ ρτw aσμρκ ητuσdariκs tτwards aσ κquiρiηrium statκ whκσ thκ σum‐ ηκr τλ passκs iσθrκasκs. Thκ rκsuρts dκmτσstratκ that θrκκp τθθurs iσ purκ aρumiσium aλtκr prτθκssiσμ ηy EC“P ηy thκ samκ mκθhaσism as iσ θτσvκσtiτσaρ θτarsκ-μraiσκd matκriaρs with iσtraμraσuρar disρτθatiτσ μρidκ aσd θρimη as thκ dτmiσaσt ratκ-θτσtrτρρiσμ dκλτrmatiτσ prτθκssκs. Thκrκλτrκ, thκ hiμhκr θrκκp rκsistaσθκ τλ prκssκd aρumiσium θaσστt ηκ a θτσsκ‐ quκσθκ τλ aσy siμσiλiθaσt θhaσμκ iσ thκ ratκ θτσtrτρρiσμ prτθκss. Thκ prκsκσt rκsuρts θτσθκrσiσμ “ρ- wt.%Mμ- . wt.%Sθ aσd “ρ- . wt.%Sθ aρρτys dτ στt θτσ‐ λirm a μκσκraρ vaρidity τλ thκ θτσθρusiτσ that prτθκssiσμ ηy EC“P τλ a θτarsκ-μraiσκd matκriaρ μivκs a pτtκσtiaρ λτr aσ imprτvκmκσt iσ thκ θrκκp rκsistaσθκ. ”y θτσtrast, thκ miσimum θrκκp ratκs λτr thκ prκssκd aρρτys arκ mτrκ rapid thaσ thκ ratκ attaiσκd iσ thκ θτarsκ-μraiσκd statκ. Thκ θrκκp mκθhaσism whiθh mτst prτηaηρy pρays thκ dτmiσaσt rτρκ iσ θrκκp τλ thκ θτarsκμraiσκd aρρτys is thκ disρτθatiτσ θρimη-ηypass mκθhaσism iσ thκ prκsκσθκ τλ κρastiθ iσtκraθtiτσ ηκtwκκσ disρτθatiτσs aσd θτhκrκσt “ρ Sθ prκθipitatκs. Strτσμ suppτrt λτr maπiσμ usκ τλ thκ samκ θτσvκσtiτσaρ θrκκp mκθhaσism iσ iσtκrprκtiσμ thκ θrκκp θharaθtκristiθ τλ prκssκd aρρτy was prκsκσtκd. “ρthτuμh it sκκms aθθκptaηρκ tτ assτθiatκ thκsκ λastκr θrκκp ratκs with thκ smaρρκr μraiσ sizκ aλtκr EC“P duκ tτ mτrκ iσtκσsivκ μraiσ ητuσdary sρidiσμ, thκrκ arκ prτηaηρκ λurthκr rκasτσs strτσμρy iσλρuκσθiσμ aσ iσtraμraσuρar dκλτrmatiτσ mκθhaσism whiθh sκκms tτ ηκ thκ ratκ-θτσtrτρρiσμ prτθκss. First, thκ prκssκd aρρτys θτσtaiσ a hiμh disρτθatiτσ dκσsity ηκ‐ θausκ τλ thκ iσtκσsκ straiσiσμ impτsκd duriσμ prκssiσμ. Sκθτσd, aσ impτrtaσt straiσ θτσtriηu‐ tiτσ duriσμ θrκκp τλ prκssκd aρρτys is prτduθκd ηy iσtκσsivκ mκsτsθaρκ sρidiσμ τλ μrτups τλ μraiσs aρτσμ shκar ηaσds. Fiσaρρy, thκ τθθurrκσθκ τλ σaστpτrκs λτrmκd duriσμ EC“P prκssiσμ at matrix/prκθipitatκ iσtκrλaθκs aσd rκsuρtiσμ iσ thκ dκθτhκsiτσ at θτhκrκσt partiθρκ surλaθκ θτuρd havκ a strτσμ κλλκθt τσ thκ θrκκp ηκhaviτur τλ prκssκd aρρτys. Θt is impτrtaσt tτ στtκ that thκ κxpκrimκσtaρ rκsuρts arκ iσ rκasτσaηρκ aμrκκmκσt with a thκτrκtiθaρ mτdκρ λτr supκrpρastiθ λρτw that was dκvκρτpκd κarρiκr λτr θτarsκ-μraiσκd aρρτys. This θτσθρusiτσ is impτrtaσt ηκ‐ θausκ τλ thκ maσy rκsuρts στw avaiρaηρκ dκmτσstratiσμ thκ τθθurrκσθκ τλ supκrpρastiθ κρτσμa‐

Eq”al-Channel Ang”lar Pressing and Creep in Ul“rafine-Grained Al”mini”m and I“s Alloys h““p://dx.doi.org/10.5772/51242

tiτσs iσ matκriaρs prτθκssκd ηy EC“P aσd ηκθausκ τλ thκ σκw pτssiηiρitiκs λτr aθhiκviσμ κxθκptiτσaρ supκrpρastiθ κρτσμatiτσs iσ matκriaρs with uρtraλiσκ μraiσ sizκs.

Acknowledgements Thκ authτrs aθπστwρκdμκ thκ λiσaσθiaρ suppτrt λτr this wτrπ ηy thκ Czκθh Sθiκσθκ Fτuσda‐ tiτσ uσdκr thκ Graσt Nτ. P / / . This wτrπ was rκaρizκd iσ CEΘTEC ª Cκσtraρ Eurτpκ‐ aσ Θσstitutκ τλ Tκθhστρτμy with rκsκarθh iσλrastruθturκ suppτrtκd ηy thκ prτοκθt CZ. . / . . / . λiσaσθκd λrτm Eurτpκaσ Rκμiτσaρ Dκvκρτpmκσt Fuσd. Wκ wτuρd ρiπκ tτ θτrdiaρρy thaσπ ρatκ Dr. Θvaσ Saxρ τλ Mathκmatiθaρ Θσstitutκ τλ thκ “θadκmy τλ Sθiκσθκs τλ thκ Czκθh Rκpuηρiθ λτr his usκλuρ adviθκs θτσθκrσiσμ thκ θτrrκθt appρiθatiτσs aσd iσtκrprκta‐ tiτσs τλ strκrκτρτμiθaρ mκthτds λτr quaσtitativκ θharaθtκrizatiτσ τλ miθrτstruθturκ.

Author details Vaθρav Sπρκσiθπa , *, Ιiri Dvτraπ , , Miρaσ Svτητda , , Pκtr Kraρ aσd Mariκ Kvapiρτva *“ddrκss aρρ θτrrκspτσdκσθκ tτ V. Sπρκσiθπa, sπρκσ@ipm.θz Θσstitutκ τλ Physiθs τλ Matκriaρs “θadκmy τλ Sθiκσθκs τλ thκ Czκθh Rκpuηρiθ, ”rστ, Czκθh Rκpuηρiθ CEΘTEC-ΘPM, Θσstitutκ τλ Physiθs τλ, Matκriaρs, “θadκmy τλ Sθiκσθκs τλ thκ Czκθh Rκpuη‐ ρiθ, ”rστ, Czκθh Rκpuηρiθ

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Chapter 2

Durability and Corrosion of Aluminium and Its Alloys: Overview, Property Space, Techniques and Developments N. L. S”kiman, X. Zho”, N. Birbilis, A.E. H”ghes, J. M. C. Mol, S. J. Garcia, X. Zho” and G. E. Thompson Addi“ional informa“ion is available a“ “he end of “he chap“er h““p://dx.doi.org/10.5772/53752

. Introduction “ρumiσium “ρ is aσ impτrtaσt struθturaρ κσμiσκκriσμ matκriaρ, its usaμκ raσπiσμ τσρy ηκhiσd λκrrτus aρρτys ”irηiρis, Mustκr κt aρ. . Thκ μrτwth iσ usaμκ aσd prτduθtiτσ τλ “ρ θτσtiσuκs tτ iσθrκasκ Davis . Thκ κxtκσsivκ usκ τλ “ρ ρiκs iσ its strκσμth dκσsity ratiτ, tτuμhσκss, aσd tτ sτmκ dκμrκκ, its θτrrτsiτσ rκsistaσθκ. Frτm a θτrrτsiτσ pκrspκθ‐ tivκ, whiθh is mτst rκρκvaσt tτ this θhaptκr, “ρ has ηκκσ a suθθκssλuρ mκtaρ usκd iσ a σum‐ ηκr τλ appρiθatiτσs λrτm θτmmτdity rτρκs, tτ struθturaρ θτmpτσκσts τλ airθraλt. “ σumηκr τλ “ρ aρρτys θaσ ηκ satisλaθtτriρy dκpρτyκd iσ κσvirτσmκσtaρ/atmτsphκriθ θτσditiτσs iσ thκir θτσvκσtiτσaρ λτrm, ρκaviσμ thκ θτrrτsiτσ prτtκθtiτσ iσdustry tτ λτθus τσ marπκt σκκds iσ mτrκ dκmaσdiσμ appρiθatiτσs suθh as thτsκ whiθh rκquirκ θτatiσμ systκms, λτr κxampρκ, thκ aκrτspaθκ iσdustry . Rκρativκρy purκ aρumiσium prκsκσts μττd θτrrτsiτσ rκsistaσθκ duκ tτ thκ λτrmatiτσ τλ a ηar‐ riκr τxidκ λiρm that is ητσdκd strτσμρy tτ its surλaθκ passivκ ρayκr aσd, that iλ damaμκd, rκλτrms immκdiatκρy iσ mτst κσvirτσmκσts i.κ. rκ-passivatiτσ Davis . This prτtκθtivκ τxidκ ρayκr is κspκθiaρρy staηρκ iσ σκar-σκutraρ sτρutiτσs τλ mτst στσ-haρidκ saρts ρκadiσμ tτ κxθκρρκσt pittiσμ rκsistaσθκ. Nκvκrthκρκss, iσ τpκσ air sτρutiτσs θτσtaiσiσμ haρidκ iτσs, with Cρ- ηκiσμ thκ mτst θτmmτσ, aρumiσium is susθκptiηρκ tτ pittiσμ θτrrτsiτσ. This prτθκss τθ‐ θurs, ηκθausκ iσ thκ prκsκσθκ τλ τxyμκσ, thκ mκtaρ is rκadiρy pτρarisκd tτ its pittiσμ pτtκσtiaρ,

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Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

aσd ηκθausκ θhρτridκs θτσtriηutκ tτ thκ λτrmatiτσ τλ sτρuηρκ θhρτriσatκd aρumiσium hydr τxidκ whiθh iσtκrλκrκs with thκ λτrmatiτσ τλ a staηρκ τxidκ τσ thκ aρumiσium surλaθκ. “ρumiσium aσd its aρρτys rκadiρy τxidisκs, iσθρudiσμ whκσ “ρ is prκsκσt iσ κithκr iσ sτρid sτρutiτσ τr iσ iσtκrmκtaρρiθ ΘM partiθρκs. Θσdustriaρ aρρτy surλaθκs hτwκvκr, tκσd tτ ηκ as hκtκrτμκσκτus as thκir uσdκrρyiσμ miθrτstruθturκs. Thκ surλaθκ τλ a wrτuμht τr θast aρρτy is ρiπκρy tτ θτσtaiσ στt τσρy aρumiσium τxidκ aρτσκ, ηut may λτr κxampρκ θτσtaiσ a λraμmκσt τλ a mixκd “ρ-Mμ τxidκ λτr aρρτys riθh iσ Mμ Harvκy, Huμhκs κt aρ. . This is primariρy ηκθausκ τλ thκ hκat τλ sκμrκμatiτσ τλ Mμ is hiμh aσd it has a λavτraηρκ λrκκ κσκrμy λτr τxidκ λτrmatiτσ. Θλ hτwκvκr aσ “ρ surλaθκ is mκθhaσiθaρρy uσdisturηκd - thκσ thκ surλaθκ τxidκ is rκρativκρy prτtκθtivκ. Thτuμh, mτst rκaρ surλaθκs havκ sτmκ sτrt τλ mκθhaσiθaρ λiσishiσμ whiθh rκsuρts iσ thκ λτrmatiτσ τλ a σκar surλaθκ dκλτrmκd ρayκr NSDL aσd shiσμρiσμ. Shiσ‐ μρiσμ τθθurs whκrκ thκ aρρτy matrix is sprκad aθrτss thκ surλaθκ iσθρudiσμ ΘM partiθρκs iσ aηrasiτσ aσd miρρiσμ Sθhτρκs, Furmaσ κt aρ. Mustκr, Huμhκs κt aρ. . This is ηκ‐ θausκ thκ ΘM partiθρκs arκ hardκr thaσ thκ surrτuσdiσμ matrix aσd ρκss susθκptiηρκ tτ dκλτr‐ matiτσ Zhτu, Liu κt aρ. . Evκσ τσ pτρishκd surλaθκs, thκ matrix aσd thκ ΘM partiθρκs rapidρy λτrm diλλκrκσt τxidκ struθturκs Ιuλλs, Huμhκs κt aρ. Ιuλλs, Huμhκs κt aρ. . This is aρmτst θκrtaiσρy duκ tτ diλλκrκσt θhκmiθaρ κσvirτσmκσts aσd diλλκrκσt κρκθtrτθhκmi‐ θaρ rκaθtiτσs τvκr thκ ΘM partiθρκs θτmparκd tτ thκ matrix. Furthκrmτrκ, thκ mτrphτρτμy aσd thκ τxidκ arκ στt θτσtiσuτus λrτm thκ ΘM partiθρκs tτ thκ matrix aσd this rκprκsκσts a pτtκσtiaρ dκλκθt sitκ iσ thκ θτσtκxt τλ θτrrτsiτσ. Fτr thκ purpτsκs τλ dκsθriptiτσs hκrκiσ, ΘM partiθρκs θaσ ηκ θρassiλiκd iσtτ thrκκ maiσ typκs i prκθipitatκs, ii θτσstituκσt partiθρκs aσd iii dispκrsτids. Prκθipitatκs arκ typiθaρρy iσ thκ shapκ τλ σκκdρκs, ρaths, pρatκs τr sphκriθaρ with thκ sizκ raσμiσμ λrτm “σμstrτms tτ λraθtiτσs τλ a miθrτmκtκr. Thκy arκ λτrmκd ηy σu‐ θρκatiτσ aσd μrτwth λrτm a supκrsaturatκd sτρid sτρutiτσ duriσμ ρτw tκmpκraturκ aμiσμ aσd may ηκ θτσθκσtratκd aρτσμ thκ μraiσ ητuσdariκs. Cτσstituκσt partiθρκs hτwκvκr, arκ rκρa‐ tivκρy ρarμκ with irrκμuρar shapκ aσd thκ sizκ θaσ ηκ up tτ miθrτmκtκrs. This typκ τλ parti‐ θρκ λτrms duriσμ sτρidiλiθatiτσ τλ thκ aρρτy aσd is στt λuρρy dissτρvκd ηy suηsκquκσt thκrmτmκθhaσiθaρ prτθκssiσμ iσθρudiσμ sτρutiτσ hκat trκatmκσts . Thκy θaσ ηκ λτuσd iσ θτρτσiκs τλ sκvκraρ ΘM θrystaρs τr diλλκrκσt θτmpτuσd typκs. Oσ thκ θτσtrary, dispκrsτids arκ smaρρ partiθρκs with sizκ raσμiσμ λrτm . tτ . miθrτmκtκrs. Thκy arκ thκrmaρρy staηρκ iσtκrmκtaρρiθs τλ a λiσκ sizκ that arκ λuσθtiτσaρ λτr θτσtrτρρiσμ μraiσ sizκ aσd rκθrystaρρisatiτσ ηκhaviτr. Dispκrsτids λτrm ηy ρτw ρκvκρ additiτσs τλ hiμhρy iσsτρuηρκ κρκmκσts suθh as Cr, Mσ τr Zr. This θhaptκr wiρρ aim tτ θτvκr sτmκ τλ thκ impτrtaσt aspκθts rκρatκd tτ thκ θτrrτsiτσ τλ “ρaρρτys, ηκariσμ iσ miσd thκ rτρκ τλ aρρτy θhκmistry. Θσ additiτσ, sτmκ τλ thκ tτpiθaρ aspκθts rκρatκd tτ tκθhσiquκs aσd τσμτiσμ dκvκρτpmκσts iσ thκ μκσκraρ λiκρd τλ “ρ-aρρτy θτrrτsiτσ arκ prκsκσtκd. “σ attκmpt has ηκκσ madκ tτ μivκ thκ rκadκr aσ τvκrviκw τλ thκ πκy tκθhσiθaρ aspκθts, ηut uσλτrtuσatκρy λτr θτmprκhκσsivκ iσsiμht iσtτ thκ tτpiθ τvκraρρ, thκ sizκ τλ this θhaptκr aρτσκ θaσστt ηκ a rκpρaθκmκσt tτ dκdiθatκd mτστμraphs τσ thκ spκθiλiθ tτpiθs at haσd στr thκ κvκr-κvτρviσμ οτurσaρ ρitκraturκ that rκprκsκσts thκ statκ τλ thκ art. Tτ aid iσ thκ traσsλκr τλ iσλτrmatiτσ, this θhaptκr has ηκκσ dividκd iσtτ a σumηκr τλ sκθtiτσs tτ trκat thκ widκρy varyiσμ tτpiθs iσdκpκσdκσtρy.

D”rabili“y and Corrosion of Al”mini”m and I“s Alloys: Overview, Proper“y Space, Techniq”es and Developmen“s h““p://dx.doi.org/10.5772/53752

. . The general performance of the Al-alloy classes Thκ θτrrτsiτσ pτtκσtiaρ τλ aσ aρumiσium aρρτy iσ a μivκσ κσvirτσmκσt is primariρy dκtκr‐ miσκd ηy thκ θτmpτsitiτσ τλ thκ aρumiσium riθh sτρid sτρutiτσ, whiθh θτσstitutκs thκ prκ‐ dτmiσaσt vτρumκ λraθtiτσ aσd arκa λraθtiτσ τλ thκ aρρτy miθrτstruθturκ Davis . Whiρκ thκ pτtκσtiaρ is στt aλλκθtκd siμσiλiθaσtρy ηy sκθτσd phasκ ΘM partiθρκs τλ miθrτsθτpiθ sizκ, thκsκ partiθρκs λrκquκσtρy havκ θτrrτsiτσ pτtκσtiaρs whκσ mκasurκd iσ isτρatiτσ diλλκriσμ λrτm that τλ thκ sτρid sτρutiτσ matrix rκsuρtiσμ iσ ρτθaρ miθrτ- μaρvaσiθ θκρρs, whκσ ΘMs arκ pτρarisκd tτ thκ θτrrτsiτσ pτtκσtiaρ τλ thκ aρρτy. Thκ rκsuρt is that ρτθaρ θurrκσts τσ thκ aρρτy surλaθκ diλλκr, κstaηρishiσμ aστdκs aσd θathτdκs. Siσθκ mτst τλ thκ θτmmκrθiaρ aρumiσium aρρτys θτσtaiσ additiτσs τλ mτrκ thaσ τσκ typκ τλ aρρτyiσμ κρκmκσt, thκ κλλκθts τλ muρtipρκ κρκmκσts τσ sτρutiτσ pτtκσtiaρ arκ apprτximatκρy additivκ. Thκ amτuσts rκtaiσκd iσ sτρid sτρutiτσ, partiθuρarρy λτr mτrκ hiμhρy aρρτyκd θτmpτsitiτσs, dκpκσd τσ prτduθtiτσ aσd thκr‐ maρ prτθκssiσμ sτ that thκ hκat trκatmκσt aσd τthκr prτθκssiσμ variaηρκs iσλρuκσθκ thκ λiσaρ κρκθtrτdκ pτtκσtiaρ τλ thκ prτduθt. ”y mκasuriσμ thκ pτtκσtiaρs τλ μraiσ ητuσdariκs aσd μraiσ ητdiκs sκparatκρy, thκ diλλκrκσθκ iσ pτtκσtiaρ rκspτσsiηρκ λτr ρτθaρ typκs τλ θτrrτsiτσ suθh as iσtκrμraσuρar θτrrτsiτσ, κxλτρia‐ tiτσ, aσd strκss θτrrτsiτσ θraθπiσμ SCC θaσ ηκ quaσtiλiκd Guiρρaumiσ aσd Maσπτwsπi Zhaσμ aσd Fraσπκρ . ”y mκasuriσμ thκ θτrrτsiτσ pτtκσtiaρ τλ ΘMs ”uθhhκit , aσd iσdκκd ηy mκasurκmκσt τλ thκ pτρarisatiτσ rκspτσsκ τλ ΘMs, κvκσ mτrκ siμσiλiθaσt iσ‐ siμhts iσtτ ρτθaρisκd θτrrτsiτσ θaσ ηκ μaiσκd ”irηiρis aσd ”uθhhκit . Suθh spκθiaρist tτp‐ iθs arκ στt dκaρt with iσ thκir κσtirκty hκrκiσ, hτwκvκr aσ aηridμκd writtκσ summary τλ thκ pκrλτrmaσθκ τλ thκ πκy “ρ-aρρτy θρassκs as τutρiσκd ηy thκ “ρumiσium “ssτθiatiτσ Hatθh is prτvidκd ηκρτw. . . . ϖϖϖ series alloys Cτrrτsiτσ rκsistaσθκ τλ aρumiσium iσθrκasκs with iσθrκasiσμ mκtaρ purity, hτwκvκr thκ usκ τλ thκ > . % μradκs is usuaρρy θτσλiσκd tτ thτsκ appρiθatiτσs whκrκ vκry hiμh θτrrτsiτσ rκ‐ sistaσθκ τr duθtiρity is rκquirκd. Θσ rκμards tτ suθh spκθiaρist appρiθatiτσs hτwκvκr, thκ aθ‐ tuaρ σumηκr τλ appρiθatiτσs arκ vκry λκw. Cτσsκquκσtρy xxx sκriκs aρρτys arκ στt θτmmτσρy usκd τr sτρd ηut dτ sκrvκ as impτrtaσt λκκdstτθπ tτ sκθτσdary aρρτy prτduθκrs τr prτduθ‐ tiτσ . Θσ thκ iσstaσθκ whκrκ μκσκraρ-purpτsκ aρρτys λτr ρiμhtρy strκssκd appρiθatiτσs arκ rκ‐ quirκd, suθh aρρτys arκ apprτximatκρy % purκ aρumiσium aσd τλλκr adκquatκ θτrrτsiτσ rκsistaσθκ iσ σκar σκutraρ κσvirτσmκσts. xxx is aρsτ sτmκtimκs usκd iσ θρaddiσμ λτr κxam‐ pρκ ““ is usκd as θρad τσ ““ Hatθh . . . ϖϖϖ series alloys Cτppκr is τσκ τλ thκ mτst θτmmτσ aρρτyiσμ additiτσs - siσθκ it has apprκθiaηρκ sτρuηiρity aσd θaσ impart siμσiλiθaσt strκσμthκσiσμ ηy prτmτtiτσ τλ aμκ hardκσiσμ iσ λaθt, thκ “ρ-Cu systκm was thκ θρassiθaρ/τriμiσaρ aμκ hardκσiσμ systκm Hatθh . Thκsκ aρρτys wκrκ thκ λτuσdatiτσ τλ thκ mτdκrσ aκrτspaθκ θτσstruθtiτσ iσdustry aσd, λτr κxampρκ ““ “ρ- . Cu- . Mμ- . Mσ , whiθh is stiρρ usκd iσ maσy appρiθatiτσs tτ this day, θaσ aθhiκvκ strκσμths iσ κxθκss τλ MPa dκpκσdiσμ τσ tκmpκr Pτρmκar .

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. . . ϖϖϖ series alloys Thκ xxx sκriκs aρρτys arκ a θτmmτdity prτduθt that is στmiσaρρy avaiρaηρκ iσ thκ λτrm τλ thiσ shκκt λτr ηκvκraμκ θaσ usaμκ . Thκ πκy aρρτyiσμ κρκmκσt, Maσμaσκsκ, has a rκρativκρy ρτw sτρuηiρity iσ aρumiσium ηut θaσ imprτvκ θτrrτsiτσ rκsistaσθκ whκσ rκmaiσiσμ iσ sτρid sτρutiτσ. “dditiτσs τλ maσμaσκsκ τλ up tτ aητut % λτrm thκ ηasis τλ thκ στσ-hκat trκataηρκ wrτuμht aρρτys with μττd θτrrτsiτσ rκsistaσθκ, mτdκratκ strκσμth i.κ. ““ tκσsiρκ strκσμth ~ MPa aσd κxθκptiτσaρρy hiμh λτrmaηiρity Pτρmκar . . . . ϖϖϖ series alloys Maμσκsium has siμσiλiθaσt sτρuηiρity iσ aρumiσium aσd imparts suηstaσtiaρ sτρid sτρutiτσ strκσμthκσiσμ whiθh θaσ aρsτ θτσtriηutκ tτ κσhaσθκd wτrπ hardκσiσμ θharaθtκristiθs Da‐ vis Pτρmκar . Thκ xxx sκriκs aρρτys θτσtaiσiσμ MPa. Oσκ θτrrτsiτσ issuκ with λuρρy wτrπ-hardκσκd xxx sκriκs aρρτys is that thκ hκavy disρτθatiτσ dκσsity aσd supκrsaturatiτσ τλ thκ sτρid sτρutiτσ with Mμ θaσ pκrmit thκ sκσsitizatiτσ τλ thκ miθrτstruθturκ ηy prκθipitatiτσ τλ dκρκtκriτus -phasκ Mμ “ρ duriσμ sustaiσκd hiμh tκmpκraturκ κxpτsurκ i.κ. iσ sκrviθκ ”aκr, Wiσdisθh κt aρ. Sκarρκs, Gτuma κt aρ. Davκσpτrt, Ωuaσ κt aρ. Gτswami, Spaστs κt aρ. . . . . ϖϖϖ series alloys Siρiθτσ additiτσs aρτσκ θaσ ρτwκr thκ mκρtiσμ pτiσt τλ aρumiσium whiρst simuρtaσκτusρy iσ‐ θrκasiσμ λρuidity whiθh is why thκ vast maοτrity τλ θast “ρ prτduθts θτσtaiσ variτus amτuσts τλ Si . Thκsκ aρρτys arκ iσθrκasiσμ iσ impτrtaσθκ iσ autτmτtivκ appρiθatiτσs λτr κσ‐ μiσκ aσd drivκ traiσ θτmpτσκσts ª hτwκvκr arκ yκt tτ rκaρisκ thκ maοτrity τλ marπκt sharκ. Hκat-trκataηρκ “ρ-Mμ-Si arκ prκdτmiσaσtρy struθturaρ matκriaρs strκσμths > MPa arκ pτs‐ siηρκ , aρρ τλ whiθh havκ aσ apprκθiaηρκ rκsistaσθκ tτ θτrrτsiτσ, immuσity tτ SCC aσd arκ wκρdaηρκ. Tτ datκ, xxx sκriκs aρρτys arκ maiσρy usκd iσ κxtrudκd λτrm, aρthτuμh iσθrκasiσμ amτuσts τλ shκκt arκ ηκiσμ prτduθκd ”irηiρis, Mustκr κt aρ. . Maμσκsium aσd siρiθτσ additiτσs arκ madκ iσ ηaρaσθκd amτuσts tτ λτrm quasi-ηiσary “ρ-Mμ Si aρρτys, τr κxθκss siρi‐ θτσ additiτσs arκ madκ ηκyτσd thκ ρκvκρ rκquirκd tτ λτrm Mμ Si. “ρρτys θτσtaiσiσμ maμσκ‐ sium aσd siρiθτσ iσ κxθκss τλ . % dκvκρτp hiμhκr strκσμth upτσ aμiσμ. . . . ϖϖϖ series alloys Thκ “ρ-Zσ-Mμ aρρτy systκm prτvidκs a raσμκ τλ θτmmκrθiaρ θτmpτsitiτσs, primariρy whκrκ strκσμth is thκ πκy rκquirκmκσt aσd this θaσ ηκ aθhiκvκd withτut rκρativκρy hiμh θτst τr θτmpρκx aρρτyiσμ . “ρ-Zσ-Mμ-Cu aρρτys havκ traditiτσaρρy τλλκrκd thκ μrκatκst pτtκσtiaρ λτr aμκ hardκσiσμ aσd as κarρy as a tκσsiρκ strκσμth τλ MPa was aθhiκvκd, hτwκvκr,

D”rabili“y and Corrosion of Al”mini”m and I“s Alloys: Overview, Proper“y Space, Techniq”es and Developmen“s h““p://dx.doi.org/10.5772/53752

suθh aρρτys wκrκ στt suitaηρκ λτr θτmmκrθiaρ usκ uσtiρ thκir hiμh susθκptiηiρity tτ strκss θτr‐ rτsiτσ θraθπiσμ θτuρd ηκ mτdκratκd Sτσμ, Diκtzκρ κt aρ. ”irηiρis, Cavaσauμh κt aρ. Liσ, Liaτ κt aρ. Lyσθh, Kσiμht κt aρ. . “κrτspaθκ σκκds ρκd tτ thκ iσtrτduθ‐ tiτσ τλ a raσμκ τλ hiμh strκσμth aκrτspaθκ aρρτys τλ whiθh ““ “ρ- . Zσ- . Mμ- . Cu- . Si- . Fκ- . Mσ- . Cr- . Ti is pκrhaps thκ mτst wκρρ-πστwσ, aσd whiθh is στw κssκσtiaρρy whτρρy supκrsκdκd ηy ““ τr thκ x λamiρy . Thκ hiμh strκσμth xxx sκriκs aρρτys dκrivκ thκir strκσμth λrτm thκ prκθipitatiτσ τλ -phasκ MμZσ aσd its prκθursτr λτrms. Thκ hκat trκatmκσt τλ thκ xxx sκriκs aρρτys is θτmpρκx, iσvτρviσμ a raσμκ τλ hκat trκatmκσts that havκ ηκκσ dκvκρτpκd tτ ηaρaσθκ strκσμth aσd strκss θτrrτsiτσ θraθπiσμ pκrλτrmaσθκ - iσθρudiσμ sκθτσdary τr mτrκ hκat trκatmκσts that θaσ iσθρudκ rκt‐ rτμrκssiτσ aσd rκ-aμiσμ Fρκθπ, Caρρκrτs κt aρ. Fκrrκr, Kτuρ κt aρ. Ziκρińsπi, Chrza‐ στwsπi κt aρ. Marρaud, Dκsθhamps κt aρ. . . . . ϖϖϖ series alloys Nτmiσaρρy rκsκrvκd λτr thκ suσdry aρρτys, xxx sκriκs aρρτys iσθρudκ a σumηκr τλ Lithium Li θτσtaiσiσμ aρρτys. Li is sτρuηρκ iσ aρumiσium tτ ~ wt% θτrrκspτσdiσμ tτ ~ at% . “s thκsκ aρρτys τλ hiμh spκθiλiθ strκσμth aσd stiλλσκss rκadiρy rκspτσd tτ hκat trκatmκσt, rκ‐ sκarθh aσd dκvκρτpmκσt has iσtκσsiλiκd duκ tτ thκir pτtκσtiaρ λτr widκsprκad usaμκ iσ aκrτ‐ spaθκ appρiθatiτσs Lavκrσia aσd Graσt Dτrward aσd Pritθhκtt Giummarra, Thτmas κt aρ. . ”asκd τσ thκ imprκssivκ ρiμhtwκiμht τλ suθh aρρτys, prκsκσt day airθraλt arκ θτmprisκd τλ sτmκ pτrtiτσ τλ “ρ-Li ηasκd aρρτys mτdκrσ μκσκratiτσs τλ whiθh aθtuaρρy iσθρudκ ρτw Li ρκvκρs aσd hκσθκ arκ στwadays dκsiμσatκd as xxx aρρτys “mηat aσd Dwara‐ πadasa Garrard Sκmκστv Giummarra, Thτmas κt aρ. . First μκσκratiτσ Li-θτσtaiσiσμ aρρτys dispρayκd sτmκ τλ thκ hiμhκst θτrrτsiτσ ratκs τλ aρρ aρumiσium aρρτys, whκrκ susθκptiηiρity tτ iσtκrμraσuρar θτrrτsiτσ was θhaρρκσμiσμ. Mτdκrσ “ρ-Cu-Li sκκm tτ havκ τvκrθτmκ this θhaρρκσμκ hτwκvκr it is aρsτ impτrtaσt tτ rκθτμσisκ that prτduθtiτσ rκ‐ quirκs spκθiaρisκd mκρtiσμ aσd θastiσμ, στt prκsκσtρy avaiρaηρκ iσ mτst θτmmκrθiaρ λaθiρitiκs.

. Corrosion of aluminium and its alloys in aqueous environment . . Environmental corrosion of aluminium Cτrrτsiτσ iσ aρumiσium aρρτys is μκσκraρρy τλ a ρτθaρ σaturκ, ηκθausκ τλ thκ sκparatiτσ τλ aστdiθ aσd θathτdiθ rκaθtiτσs aσd sτρutiτσ rκsistaσθκ ρimitiσμ thκ μaρvaσiθ θκρρ sizκ. Thκ ηa‐ siθ aστdiθ rκaθtiτσ is mκtaρ dissτρutiτσ “ρ → “ρ ++ κWhiρκ thκ θathτdiθ rκaθtiτσs arκ τxyμκσ rκduθtiτσ O + H O + κ- → OHτr hydrτμκσ rκduθtiτσ iσ aθidiλiκd sτρutiτσ suθh as iσ a pit κσvirτσmκσt as a rκsuρt τλ aρumi‐ σium iτσ hydrτρysis

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H++ κ → H Θt is thκ iσtκraθtiτσ ηκtwκκσ ρτθaρ θathτdκs aσd aστdκs aσd thκ aρρτy matrix that ρκads tτ σκarρy aρρ λτrms τλ θτrrτsiτσ iσ aρumiσium aρρτys. Thκsκ iσθρudκ pittiσμ θτrrτsiτσ, sκρκθtivκ dissτρutiτσ, trκσθhiσμ, iσtκrmκtaρρiθ partiθρκ κtθhτut, iσtκrμraσuρar attaθπ aσd κxλτρiatiτσ θτrrτsiτσ. Surλaθκ aσd suηsurλaθκ μraiσ κtθhτut is aρsτ iσλρuκσθκd ηy μraiσ κσκrμy whiθh is dκrivκd λrτm μraiσ dκλκθt dκσsity. Graiσ κtθhτut, has a siμσiλiθaσt rτρκ iσ κxλτρiatiτσ θτrrτ‐ siτσ siσθκ thκ vτρumκ τλ hydratκd aρumiσium τxidκ μκσκratκd duriσμ dissτρutiτσ is ρarμκr thaσ thκ τriμiσaρ vτρumκ τλ thκ μraiσ. Thκ μκσκraρ θτσsκσsus λτr “ρ aσd its aρρτys is that thκy arκ rκsistaσt tτwards θτrrτsiτσ iσ miρdρy aμμrκssivκ aquκτus κσvirτσmκσts. Thκ prτtκθtivκ τxidκ ρayκr rκprκsκσts thκ thκrmτ‐ dyσamiθ staηiρity τλ “ρ aρρτys iσ θτrrτsivκ κσvirτσmκσt - aθtiσμ as a physiθaρ ηarriκr as wκρρ as θapaηρκ tτ rκpair itsκρλ iσ τxidiziσμ κσvirτσmκσts iλ damaμκd. Whiρκ thκ passivκ ρayκr ηrκaπdτwσ mκθhaσism ηy θhρτridκ iτσs is stiρρ iσ dκηatκ Satτ MθCaλλκrty duκ tτ thκ θτmpρκxity τλ thκ prτθκss Szπρarsπa-Smiaρτwsπa , thκ μκσκraρ θτσsκσsus is that ρτ‐ θaρizκd attaθπ starts ηy adsτrptiτσ τλ aμμrκssivκ aσiτσs aσd λτrmatiτσ τλ sτρuηρκ traσsitiτσaρ θτmpρκxκs with thκ θatiτσs at thκ τxidκ surλaθκ. Thκrmτdyσamiθ priσθipρκs tτ κxpρaiσ aσd prκdiθt thκ passivity phκστmκστσ that θτσtrτρs thκ θτrrτsiτσ ηκhaviτr τλ “ρ arκ summarisκd ηy Pτurηaix-typκ aσaρysis. This rκsuρts iσ a pρτt τλ pτtκσtiaρ vs. pH ηasκd τσ thκ κρκθtrτ‐ θhκmiθaρ rκaθtiτσ τλ thκ spκθiκs iσvτρvκd, thκ rκprκsκσtatiτσ πστwσ as a Pτurηaix diaμram Pτurηaix as shτwσ iσ Fiμurκ .

Figure 1. E-pH diagram for p”re Al a“ 25˚C in aq”eo”s sol”“ion (adap“ed from Po”rbaix 1974). The lines (a) and (b) correspond “o wa“er s“abili“y and i“s decomposed prod”c“.

D”rabili“y and Corrosion of Al”mini”m and I“s Alloys: Overview, Proper“y Space, Techniq”es and Developmen“s h““p://dx.doi.org/10.5772/53752

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Θt is sκκσ that “ρ is στmiσaρρy passivκ iσ thκ pH raσμκ τλ ~ tτ duκ tτ thκ prκsκσθκ τλ aσ “ρ O λiρm. Θσ κσvirτσmκσts that dκviatκ λrτm thκ σκar σκutraρ raσμκ, thκ θτσtiσuity τλ this λiρm θaσ ηκ disruptκd iσ whiθh thκ λiρm ηκθτmκs sτρuηρκ, λaθiρitatiσμ thκ rκρativκρy rapid τλ dissτρutiτσ thκ aρρτy. Θσ thκ aθidiθ raσμκ, “ρ is τxidisκd ηy λτrmiσμ “ρ +, whiρst “ρO - τθθurs iσ aρπaρiσκ raσμκ. Thκ E-pH diaμram μivκs aσ imprκssiτσ that θτrrτsiτσ prκdiθtiτσ is a straiμhtλτrward prτθ‐ κss, hτwκvκr iσ aθtuaρ κσμiσκκriσμ appρiθatiτσs, thκrκ arκ sκvκraρ variaηρκs that wκrκσ~t θτσ‐ sidκrκd ηy Pτurηaix. Thκsκ iσθρudκ i thκ prκsκσθκ τλ aρρτyiσμ κρκmκσts iσ mτst κσμiσκκriσμ mκtaρs ii thκ prκsκσθκ τλ suηstaσθκs iσ thκ κρκθtrτρytκ suθh as θhρτridκ aρηκit that this has ηκκσ addrκssκd iσ mτrκ mτdκrσ θτmputatiτσs , iii thκ τpκratiσμ tκmpκraturκ τλ thκ aρρτy, iv thκ mτdκ τλ θτrrτsiτσ, aσd v thκ ratκ τλ rκaθtiτσ. Taπiσμ thκsκ λaθtτrs iσtτ aθθτuσt is στmiσaρρy dτσκ τσ a θasκ ηy θasκ i.κ. aρρτy ηy aρρτy ηasis, aσd a rκvisκd vκrsiτσ τλ aσ E-pH diaμram λτr xxx sκriκs aρρτys iσ . M sτdium θhρτridκ is μivκσ iσ Fiμurκ .

Uniform corrosion Pitting corrosion Partial corrosion

Passivation Pitting corrosion

Uniform corrosion

Figure 2. Mode of corrosion based on experimen“al da“a for AA5086 in “he presence of 0.5M sodi”m chloride (adap“‐ ed from Gimenez, Ramea” e“ al. 1981)

Fiμurκ iσdiθatκs wiσdτws whκrκ ρτθaρizκd attaθπ is hiμhρy pτssiηρκ iσ thκ suppτsκd passivκ rκμiτσ Gimκσκz, Ramκau κt aρ. . Θt is aρsτ sκκσ that ρτθaρisκd attaθπ is pτssiηρκ aθrτss thκ whτρκ raσμκ τλ pH dκpκσdiσμ τσ thκ spκθiλiθ pτtκσtiaρ. Oσκ shτuρd thκrκλτrκ στt rκρy sτρκρy τσ

   

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Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

thκ Pτurηaix diaμram as a dirκθt iσdκx tτ aθtuaρ θτrrτsiτσ ratκs, with ratκs σκκdiσμ tτ ηκ iσdκ‐ pκσdκσtρy mκasurκd λτr a μivκσ aρρτy-κρκθtrτρytκ θτmηiσatiτσ “mηat aσd Dwaraπadasa . Fiσaρρy, whiρst στt tτ ηκ disθussκd iσ dκtaiρ hκrκ, it is prudκσt tτ iσdiθatκ that κλλκθtivκρy aρρ “ρ-aρρτys dτ στt attaiσ praθtiθaρ/κmpiriθaρ immuσity as κvidκσθκ iσ Fiμurκ . Cathτdiθ pτρar‐ isatiτσ tκσds tτ θτσtriηutκ tτ aρρτy dκtκriτratiτσ ηy twτ mτdκs. Firstρy, thκ aθθumuρatiτσ τλ hy‐ drτxyρ iτσs at thκ “ρ-surλaθκ wiρρ θausκ θhκmiθaρ dissτρutiτσ τλ thκ “ρ. Sκθτσdρy, “ρ is a vκry strτσμ hydridκ λτrmκr, aσd hydrτμκσ λrτm thκ θathτdiθ rκaθtiτσ at suθh σκμativκ pτtκσtiaρs wiρρ sκrvκ θτmηiσκ with “ρ tτ λτrm hydridκs Pκrrauρt . . . Kinetic stability of aluminium alloys Kiσκtiθs rκprκsκσts thκ ratκ τλ rκaθtiτσ duriσμ θτrrτsiτσ. Whκσ κxpτsκd tτ aσ aquκτus κσvi‐ rτσmκσt, mκtaρs staηiρisκ tτ a vaρuκ τλ κρκθtrτθhκmiθaρ pτtκσtiaρ that is θharaθtκristiθ τλ thκ matκriaρ aσd its θτmpτsitiτσ λτr a μivκσ κρκθtrτρytκ. This pτtκσtiaρ is thκ pτtκσtiaρ at whiθh aστdiθ aσd θathτdiθ rκaθtiτσs upτσ thκ mκtaρ surλaθκ arκ κquaρ, aσd thκ vaρuκ τλ this pτtκσ‐ tiaρ is thus siμσiλiθaσtρy iσλρuκσθκd ηy λaθtτrs that θaσ aρtκr thκ rκρativκ ratκs τλ aστdiθ τr θathτdiθ rκaθtiτσ κλλiθiκσθy upτσ thκ mκtaρ surλaθκ i.κ. aρρτyiσμ, prκθipitatκ statκ, κtθ. . Mτst typiθaρρy, thκ pτtκσtiτdyσamiθ pτρarisatiτσ tκst is usκd tτ θharaθtκrisκ thκ θτrrτsiτσ pκr‐ λτrmaσθκ τλ aσ aρρτy as λar as dκtκrmiσatiτσ τλ mκθhaσistiθ aspκθts λrτm aσ iσstaσtaσκτus tκst . This mκthτd μivκs vitaρ πiσκtiθ iσλτrmatiτσ suθh as θurrκσt dκσsity τvκr a raσμκ τλ pτtκσtiaρs, pittiσμ pτtκσtiaρ iλ it κxists , θτrrτsiτσ pτtκσtiaρ, thκ passivκ θurrκσt dκσsity aσd pτtκσtiaρρy mτrκ iσλτrmatiτσ iσ rκvκrsκ sθaσs, κtθ. Thus λaθtτrs aλλκθtiσμ θτrrτsiτσ as disθussκd iσ thκ prκ‐ viτus sκθtiτσs θaσ ηκ κvaρuatκd with muθh hiμhκr θτσλidκσθκ. Fτr κxampρκ, Fiμurκ shτws a pτρarisatiτσ θurvκ τλ Purκ “ρ θτmparκ tτ ““ -T “ρ- . Cu- . Mμ- . Mσ iσ . M NaCρ.

Figure 3. Polarisa“ion c”rve of p”re Al and AA2024-T3 exposed “o 0.1M NaCl for 7 days collec“ed a“ 1mV/s-1 (adap“ed from (S”kiman, Birbilis e“ al. 2010))

D”rabili“y and Corrosion of Al”mini”m and I“s Alloys: Overview, Proper“y Space, Techniq”es and Developmen“s h““p://dx.doi.org/10.5772/53752

Cτmparisτσ τλ aρρτy ηκhaviτr aσd dτmiσaσt rκaθtiτσs θaσ ηκ madκ iσ a quaσtitativκ maσ‐ σκr. Thκ aστdiθ ηraσθh τλ thκ pτρarisatiτσ θurvκ μivκs iσλτrmatiτσ rκρatκd tτ thκ aστdiθ/ dissτρutiτσ rκaθtiτσ whiρκ thκ θathτdiθ ηraσθh rκprκsκσts thκ rκduθtiτσ rκaθtiτσ στmiσaρρy τxyμκσ rκduθtiτσ, ηut at ρτwκr pτtκσtiaρs τr iσ strτσμ aθids, watκr rκduθtiτσ . Thκ additiτσ τλ mτrκ στηρκ aρρτyiσμ κρκmκσts typiθaρρy iσθrκasκs thκ θτrrτsiτσ pτtκσtiaρ tτ mτrκ στηρκ vaρuκs Davis aσd this is dramatiθaρρy τηsκrvκd iσ Fiμurκ . This κσστηρκmκσt hτwκv‐ κr dτκs στt θτrrκρatκ tτ thκ ratκ τλ θτrrτsiτσ as οudμκd ηy Fiμurκ , whκrκηy wκ sκκ thκ purκ “ρ vκrsus ““ -T has a diλλκrκσθκ iσ pτtκσtiaρ τλ ~ . V. Θσ additiτσ, thκ maiσ praθ‐ tiθaρ thrκat λτr “ρ aρρτys is ρτθaρisκd attaθπ suθh as pittiσμ, sτ iσ that vκiσ, a mτrκ στηρκ vaρuκ τλ pittiσμ pτtκσtiaρ dτκs στt σκθκssariρy siμσiλy a ηκttκr θτrrτsiτσ rκsistaσθκ Fraσπκρ ”irηiρis aσd ”uθhhκit . Rathκr μκσκraρρy, thκ κρκθtrτθhκmiθaρ rκaθtiτσs upτσ “ρ-aρρτys arκ hκaviρy iσλρuκσθκd ηy thκ θhκmistry aσd miθrτstruθturκ τλ thκ aρρτy ª whiθh wκ attκmpt tτ disθuss iσ thκ λτρρτwiσμ sκθtiτσ. Mτviσμ ηκyτσd pτtκσtiτdyσamiθ pτρarisatiτσ tτwards a truκ mκasurκ τλ πiσκtiθ staηiρity iσ thκ E-pH dτmaiσ simiρar iσ θτσθκpt tτ Pτurηaix diaμrams hτwκvκr whiθh μivκ }spκκd~ aσd στt οust thκrmτdyσamiθ ρiπκρihττd thκrκ arκ tκsts whiθh θaσ ηκ dτσκ iσ this rκμard. Θσ τrdκr tτ dκvκρτp aσ imprτvκd uσdκrstaσdiσμ τλ τvκraρρ πiσκtiθ staηiρity τλ a mκtaρ τvκr thκ pτtκσ‐ tiaρ-pH spaθκ, mκthτds iσθρudiσμ thκ stairθasκ pτtκσtiτ-κρκθtrτθhκmiθaρ impκdaσθκ spκθtrτ‐ sθτpy SPEΘS θaσ ηκ usκd tτ κstaηρish sτ-θaρρκd πiσκtiθ staηiρity diaμrams, as prκviτusρy dκmτσstratκd λτr purκ “ρ Zhτu, ”irηiρis κt aρ. aσd dκpiθtκd iσ Fiμurκ . Thκ spκθiλiθs τλ SPEΘS wiρρ ηκ iσtrτduθκd iσ sκθtiτσ . .

a

η

Figure 4. Con“o”r plo“s of 1/RP for “he E-pH space and “heir da“a for (a) A por“ion of a 99.9999% Al ingo“ single crys‐ “al and (b) a polycrys“alline specimen from “he iden“ical ingo“ in (a) (adap“ed from (Zho”, Birbilis e“ al. 2010)

Θσ Fiμurκ , prκsκσtatiτσ τλ thκ rκθiprτθaρ τλ pτρarisatiτσ rκsistaσθκ /RP is thκ mκtriθ τλ rκ‐ aθtiτσ }spκκd~, as it is prτpτrtiτσaρ tτ thκ rκaθtiτσ ratκ at a μivκσ θτσditiτσ. Thκ iσλρuκσθκ τλ pτtκσtiaρ aσd pH is prκsκσtκd στt τσρy λτr purκ “ρ iσ thκ sampρκ whiθh was siσμρκ θrystaρ,

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ηut aρsτ λτr a pτρyθrystaρρiσκ sampρκ. “s a rκsuρt, τσκ is aρsτ aηρκ tτ assκss thκ κλλκθt τλ μraiσ struθturκ λrτm Fiμurκ . Mτst impτrtaσtρy hτwκvκr, Fiμurκ rκvκaρs that thκ ratκ τλ rκaθtiτσ stays iσ a ρτw raσμκ iσ arκas that κxtκσd ηκyτσd that τλ thκ Pτurηaix diaμram iσ tκrms τλ θκrtaiσ E-pH θτmηiσatiτσs ª iσdiθatiσμ that aρthτuμh “ρ may ηκ iσ a thκrmτdyσamiθaρρy uσstaηρκ rκμiτσ, thκ rκaθtiτσ ratκ θaσ ηκ maiσtaiσκd tτ ηκ ρτw κστuμh tτ maπκ it stiρρ ηκ usκ‐ λuρ iσ aσ κσμiσκκriσμ θτσtκxt. Simiρarρy, thκrκ arκ rκμiτσs τλ hiμh pτtκσtiaρ whκrκ purκ aρu‐ miσium may ηκ iσ a thκrmτdyσamiθaρρy staηρκ rκμiτσ, ηut uσusaηρκ ª τwiσμ tτ traσspassivκ dissτρutiτσ. Fiσaρρy, iσ tκrms τλ miθrτstruθturκ κλλκθts, it is sκκσ that thκ κxaθt samκ matκriaρ θaσ havκ a diλλκrκσt πiσκtiθ rκspτσsκ ηasκd τσ struθturaρ λaθtτrs aρτσκ. Suθh diλλκrκσθκs arκ στt dκtκθtiηρκ τr prκdiθtκd λrτm thκrmτdyσamiθ aσaρysis iσ aσy way, aσd this hiμhρiμhts thκ impτrtaσθκ τλ apprτaθhκs whiθh prτvidκ πiσκtiθ iσλτrmatiτσ tτ mκκt dκmaσds τλ κσμiσκκr‐ iσμ appρiθatiτσs.

. . The property space and corrosion property profile of aluminium alloys “s tκθhστρτμiκs θτσtiσuκ tτ advaσθκ with mτrκ θhaρρκσμiσμ appρiθatiτσs aσd κσvirτσmκσts, a μκσκraρ uσdκrstaσdiσμ τλ duraηiρity ρimits aθrτss thκ θρass τλ “ρ-aρρτys is κssκσtiaρ. Dura‐ ηiρity σκκdκd iσ a ηrτad sκσsκ is thκ aηiρity tτ withstaσd aσ κσvirτσmκσt whiρκ maiσtaiσiσμ mκθhaσiθaρ iσtκμrity. This iσdiθatκs a rκquirκmκσt tτ uσdκrstaσd thκ prτpκrty spaθκ λτr “ρ aσd its aρρτys. Fiμurκ shτws a trκσd that is iσ ρiσκ with thκ στtiτσ that iσθrκasκs iσ hard‐ σκss usκd hκrκ as a prτxy tτ yiκρd strκσμth shτw iσθrκasκs iσ θτrrτsiτσ ratκ.

Figure 5. Corrosion ra“e as de“ermined from weigh“ loss da“a for commercial Al alloys collec“ed af“er 14 days expo‐ s”re in q”iescen“ 0.1M NaCl presen“ed agains“ alloy hardness.

D”rabili“y and Corrosion of Al”mini”m and I“s Alloys: Overview, Proper“y Space, Techniq”es and Developmen“s h““p://dx.doi.org/10.5772/53752

Frτm Fiμurκ , it θaσ ηκ arμuκd that thκ data is dividκd iσtτ twτ maiσ μrτups, τσκ at κaθh κσd τλ thκ θτrrτsiτσ ratκ spκθtrum. Hiμh hardσκss/strκσμth aρumiσium aρρτys wκrκ λτuσd tτ pτpuρatκ thκ hiμh θτrrτsiτσ ratκ spaθκ. This is iσ θτσtrast tτ thκ mκdium tτ ρτw hardσκss/ strκσμth aρρτys that rκvκaρκd θτσsidκraηρy ρτwκr θτrrτsiτσ ratκs. Thκ aρρτys that shτw thκ hiμhκst θτrrτsiτσ ratκs arκ thκ }prκθipitatiτσ hardκσaηρκ~ λamiρy. ”κsidκs thκ hiμh σumηκr dκσsity τλ prκθipitatκ partiθρκs iσ suθh aρρτys, thκy aρsτ θτσtaiσ aσ apprκθiaηρκ pτpuρatiτσ τλ θτσstituκσt typκ partiθρκs Chκσ, Gaτ κt aρ. Wκi “σdrκatta, Tκrryσ κt aρ. Θρκvηarκ, Sθhσκidκr κt aρ. ”irηiρis, Cavaσauμh κt aρ. ”τaμ, Huμhκs κt aρ. Huμhκs, MaθRaκ κt aρ. Ψu, ”irηiρis κt aρ. . Thκsκ partiθρκs arκ iσdustriaρρy σκθκssa‐ ry, siσθκ thκ θτmpρκx θhκmistry τλ prκθipitatiτσ hardκσaηρκ aρρτys that θaσ θτσtaiσ up tτ aρρτyiσμ κρκmκσts havκ siμσiλiθaσt aρρτyiσμ additiτσs addκd via aρρτy riθh mastκr aρρτys. Θt is aρsτ τηsκrvκd that thκ aρρτys that shτw thκ hiμhκst θτrrτsiτσ ratκs aρsτ θτσtaiσ apprκθia‐ ηρκ amτuσt τλ θτppκr. Thκ pρτt iσ Fiμurκ aρρτws τσκ tτ idκσtiλy a rκμiτσ τλ prτpκrty spaθκ at thκ tτp ρκλt θτrσκr that has pτtκσtiaρ λτr λuturκ aρρτys, with τσμτiσμ κλλτrts aimiσμ tτ rκaθh suθh spaθκ iσ addi‐ tiτσ tτ θτσtrτρρiσμ duθtiρity . Eλλτrts that rκμard iσ arκ uσdκrway, λτθusiσμ τσ θτrrτsiτσ ratκ Carrτρρ, Gτuma κt aρ. Nτrτva, Gaσiκv κt aρ. Rτsaρηiστ, “σμκρiσi κt aρ. Cav‐ aσauμh, ”irηiρis κt aρ. Luθκσtκ aσd Sθuρρy Faσμ, Chκσ κt aρ. Gravκr, Pκdκr‐ sκσ κt aρ. Raρstτσ, ”irηiρis κt aρ. Taσ aσd “ρρκσ Ψu, ”irηiρis κt aρ. ”ruσσκr, ”irηiρis κt aρ. aσd strκσμth Pττρκ, Sκtκr κt aρ. Pκdκrsκσ aσd “rσηκrμ Fuρρκr, Krausκ κt aρ. Raviprasad, Hutθhiσsτσ κt aρ. Lκκ, Shiσ κt aρ. Oρi‐ vκira Ιr, dκ ”arrτs κt aρ. Zhaτ, Liaτ κt aρ. Kim, Kim κt aρ. Tκixκira, ”τurμκτis κt aρ. MθKκσziκ aσd Lapτvτπ Waσμ, Zhaσμ κt aρ. Puμa, Cτsta κt aρ. Zhτσμ, Fκσμ κt aρ. Wκstκrmaσσ, Hτppκrstad κt aρ. . Hτwκvκr, suθh studiκs arκ dτσκ iσdκpκσdκσtρy τλ ητth prτpκrtiκs thus thκ symηiτtiθ κλλκθt θaσ~t ηκ rκadiρy κvaρuatκd tτ datκ.

. Corrosion of aluminium and its alloys in aqueous environment . . The role of chemistry on corrosion “ρρτyiσμ κρκmκσts arκ addκd tτ aρumiσium λτr variτus rκasτσs, with imprτviσμ mκθhaσiθaρ prτpκrtiκs thκ priσθipaρ rκasτσ. Thκsκ κρκmκσts iσtrτduθκ hκtκrτμκσκity iσtτ thκ miθrτstruθ‐ turκ, whiθh is thκ maiσ θausκ τλ ρτθaρisκd θτrrτsiτσ that iσitiatκs iσ thκ λτrm τλ pittiσμ. Eaθh aρρτyiσμ κρκmκσt has a diλλκrκσt κλλκθt τσ thκ θτrrτsiτσ τλ “ρ, aσd iσ this sκθtiτσ wκ ηriefly disθuss thκ rτρκ τλ aρρτyiσμ κρκmκσts τσ θτrrτsiτσ τλ “ρ. . . . Influenθe of magnesium Mμ is τσκ τλ thκ maοτr κρκmκσts addκd tτ “ρ tτ imprτvκ mκθhaσiθaρ prτpκrtiκs ηy sτρid sτρ‐ utiτσ strκσμthκσiσμ ª aσd θaσ ηκ λτuσd iσ xxx aρρτys, as wκρρ as xxx, xxx, xxx aσd xxx θτmmκrθiaρ aρρτys. Mμ θaσ staηiρizκ GP zτσκs, has a hiμh sτρuηiρity iσ “ρ aσd dκθrκasκs thκ aρρτy dκσsity. Muρρκr aσd Gaρvκρκ shτwκd that Mμ whκσ prκsκσt iσ sτρid sτρutiτσ dτκs στt

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havκ a siμσiλiθaσt κλλκθt τσ thκ pittiσμ θτrrτsiτσ τλ “ρ whiθh θaσ ηκ uσdκrstττd τσ thκ ηasis τλ staσdard pτtκσtiaρs τλ “ρ aσd Mμ Muρρκr aσd Gaρvκρκ . Mτrκτvκr, Mμ dκθrκasκs thκ ratκ τλ thκ θathτdiθ rκaθtiτσ whκσ prκsκσt iσ sτρid sτρutiτσ, iσθrκasiσμ θτrrτsiτσ rκsistaσθκ, whiθh may appκar θτuσtκriσtuitivκ, ηut is rathκr τηviτus as Mμ has a vκry ρτw κxθhaσμκ θurrκσt dκσsity aσd hκσθκ rκtards thκ θathτdiθ rκaθtiτσ . Θσ θτσtrast, κxθκss amτuσts τλ Mμ iσ thκ aρρτy τr a ρτσμ tκrm κxpτsurκ tτ κρκvatκd tκmpκraturκ wiρρ θausκ thκ prκθipitatiτσ τλ κithκr “ρ Mμ τr “ρ Mμ Sκarρκs, Gτuma κt aρ. Davκσpτrt, Ωuaσ κt aρ. Oμuτθha, “diμuσ κt aρ. Ιaiσ, Lim κt aρ. . Thκsκ phasκs λτrm typiθaρρy aρτσμ μraiσ ητuσdariκs ”aκr, Wiσdisθh κt aρ. Gτswami, Spaστs κt aρ. aσd arκ πστwσ tτ ηκ aστdiθ with rκspκθt tτ “ρ matrix thκrκλτrκ prτσκ tτ ρτθaρizκd θτrrτsiτσ Vκtraστ, Wiρρiλτrd κt aρ. “ηaρρκ, ”κthκσθτurt κt aρ. Ιτσκs, ”aκr κt aρ. ”ruσσκr, May κt aρ. . Mμ iσ xxx, xxx aσd xxx aρρτys hτwκvκr, λτrms prκθipitatκs with τthκr aρρτyiσμ κρκmκσts tτ strκσμthκσ thκ aρρτy whκrκ rτρκ τλ Mμ maiσρy dκpκσds upτσ thκ τthκr aρρτyiσμ additiτσs Riσμκr, Hτστ κt aρ. ”uθhhκit, Graσt κt aρ. Campκstriσi, vaσ Wκstiσμ κt aρ. Guiρρaumiσ aσd Maσπτwsπi Eθπκrmaσσ, Sutκr κt aρ. . . . . Influenθe of siliθon Thκ additiτσ τλ Si iσ θτσοuσθtiτσ with Mμ, whiθh is typiθaρ iσ xxx sκriκs “ρ aρρτys, aρρτws Mμ Si partiθρκs tτ prκθipitatκ. Thκrκ is vast ρitκraturκ τσ thκ θhκmiθaρ θτmpτsitiτσ τλ thκ MμSi phasκ aσd its rτρκ τσ mκθhaσiθaρ prτpκrtiκs Hirth, Marshaρρ κt aρ. Usta, Gρiθπsmaσ κt aρ. Stκρρiσμ, Θrrκtiκr κt aρ. Eθπκrmaσσ, Sutκr κt aρ. Zκσμ, Wκi κt aρ. . This partiθρκ is ηκσκλiθiaρ iσ tκrms τλ iσθrκasiσμ strκσμth ηut rκσdκrs thκ aρρτy prτσκ tτ ρτθaρ‐ isκd θτrrτsiτσ Eθπκrmaσσ, Sutκr κt aρ. . Thκ κρκθtrτθhκmiθaρ ηκhaviτr τλ Mμ Si was iσ‐ vκstiμatκd rκθκσtρy aσd it was shτwσ that Mμ Si rκmaiσs mτrκ }aστdiθ~ i.κ.. ρκss στηρκ thaσ thκ matrix iσ “ρ-aρρτys. “s a θτσsκquκσθκ τλ this, Mμ Si rκmaiσs aστdiθ aσd uσdκrμτκs sκ‐ ρκθtivκ dissτρutiτσ iσ thκ “ρ-matrix. Sτmκ xxx sκriκs aρρτys θτσtaiσ κxθκss Si. Exθκss amτuσt τλ Si hτwκvκr iσθrκasκs thκ θathτdiθ rκaθtiτσ ratκ Eθπκrmaσσ, Sutκr κt aρ. aσd arκ uσ‐ λavτraηρκ siσθκ Si tκσds tτ ηκ prκsκσt aρτσμ thκ μraiσ ητuσdary aσd this may ρκad tτ iσtκr‐ μraσuρar θτrrτsiτσ aσd strκss θτrrτsiτσ θraθπiσμ Guiρρaumiσ aσd Maσπτwsπi Larsκσ, Waρmsρκy κt aρ. Zκσμ, Wκi κt aρ. . . . . Influenθe of θopper Thκ prκsκσθκ τλ Cu is viκwκd as dκtrimκσtaρ tτ θτrrτsiτσ duκ tτ thκ λτrmatiτσ τλ θathτdiθ partiθρκs θapaηρκ τλ sustaiσiσμ thκ θathτdiθ rκaθtiτσ ρτθaρρy aσd κλλiθiκσtρy, suθh as “ρ Cu aσd “ρCu Mμ. Θσ sτmκ θasκs whκrκ ρτw Cu θτσtκσt is usκd, thκ impaθt τλ Cu is miσimaρ, hτwκvκr μivκσ that θτrrτsiτσ is στt thκ priσθipaρ aρρτy dκsiμσ θritκria iσ mτst iσstaσθκ, Cu is θτmmτσ iσ maσy mτst “ρ-aρρτys. Thκ xxx sκriκs aρρτys arκ Cu riθh, hτwκvκr Cu is addκd tτ τthκr aρρτy θρassκs suθh as thκ xxx sκriκs whκrκ it θaσ iσθrκasκ strκσμth whκσ prκsκσt iσ traθκ amτuσts, aσd aρsτ κσhaσθκ prκθipitatiτσ hardκσiσμ. Thκ samκ is truκ iσ xxx aρρτys, with mτst mτdκrσ aκrτspaθκ aρρτys haviσμ apprκθiaηρκ amτuσts τλ Cu that θaσ iσθrκasκ strκσμth ηy mτdiλyiσμ prκθipitatiτσ aσd miσimisiσμ SCC via iσθτrpτratiτσ iσtτ prκθipitatκs suθh as Mμ Zσ,Cu .

D”rabili“y and Corrosion of Al”mini”m and I“s Alloys: Overview, Proper“y Space, Techniq”es and Developmen“s h““p://dx.doi.org/10.5772/53752

Θσ μκσκraρ hτwκvκr, thκrκ is stiρρ sτmκ dκηatκ τσ thκ prκθisκ rτρκ τλ Cu, whiθh aρsτ dκpκσds τσ thκ tκmpκr θτσditiτσ. Muρρκr aσd ”uθhhκit λτuσd that Cu iσ thκ λτrm τλ sτρid sτρutiτσ dκθrκasκs pittiσμ susθκptiηiρity thrτuμh thκ κσστηρκmκσt τλ pittiσμ pτtκσtiaρ. Whiρκ Muρρκr aσd Gaρvκρκ rκpτrtκd aσ iσθrκasκ iσ pittiσμ pτtκσtiaρ λτr sτρid sτρutiτσ θτσtκσt τλ Cu up tτ wt%. Θσ thκ θasκ τλ “ρ-Cu-Mμ aρρτys whiθh θτσtaiσ S phasκ “ρ CuMμ , ρarμκ diλλκrκσθκs iσ sτρutiτσ pτtκσtiaρ ηκtwκκσ Cu hiμhρy στηρκ aσd Mμ κxist, with siμσiλiθaσt λτθus τσ θτrrτ‐ siτσ τλ S phasκ ”uθhhκit, Graσt κt aρ. Guiρρaumiσ aσd Maσπτwsπi ”uθhhκit, Mτσtκs κt aρ. Θρκvηarκ, Sθhσκidκr κt aρ. ”τaμ, Huμhκs κt aρ. rκvκaρiσμ dκaρ‐ ρτyiσμ aσd sκρκθtivκ dissτρutiτσ that ρκads tτ prκλκrκσtiaρ dissτρutiτσ τλ Mμ aσd “ρ with Cu rκmσaσt ηκiσμ rκdistriηutκd at τr σκar thκ sitκ τλ thκ “ρ CuMμ. “ raσμκ τλ τthκr partiθρκs assτθiatκd with Cu havκ ηκκσ rκpτrtκd suθh as “ρ Cu Fκ. Hτwκvκr rκθκσt miθrτprτηκ stud‐ iκs τλ a σumηκr τλ ηatθhκs τλ ““ -T iσdiθatκ λivκ θτmmτσ θτmpτsitiτσs aθrτss mτd‐ κrσ aρρτys whiθh dτ στt havκ thκ samκ θτmpτsitiτσ as τρdκr aρρτy stτθπ iσdiθatiσμ that this is stiρρ aσ aθtivκ arκa τλ rκsκarθh Huμhκs, Gρκσσ κt aρ. . Θσ μκσκraρ, Cu, τr Cu θτσtaiσiσμ partiθρκs arκ θapaηρκ τλ suppτrtiσμ hiμh τxyμκσ rκduθtiτσs ratκs aσd hκσθκ uσdκsiraηρκ λrτm θτrrτsiτσ pκrspκθtivκ Mazurπiκwiθz aσd Piτtrτwsπi Sθuρρy, Kσiμht κt aρ. ”uθhhκit ”irηiρis, Cavaσauμh κt aρ. . . . . Influenθe of zinθ Θσ hiμh strκσμth θτmmκrθiaρ aρumiσium aρρτys suθh xxx sκriκs aρρτys, Zσ is addκd tτ stimu‐ ρatκ prκθipitatiτσ hardκσiσμ. “ρρτys θτσtaiσiσμ hiμh ρκvκρs τλ Zσ suθh as thκ mτdκrσ aκrτ‐ spaθκ aρρτys aσd arκ amτσμst thκ hiμhκst strκσμths τλ “ρ-aρρτys τwiσμ tτ thκ hiμh σumηκr dκσsity τλ prκθipitatκs suθh as MμZσ whiθh is κvκσρy distriηutκd thrτuμhτut thκ “ρ matrix Riσμκr, Hτστ κt aρ. “σdrκatta, Tκrryσ κt aρ. Sha aσd Cκrκzτ ”irηiρis aσd ”uθhhκit Pτρmκar iσ xxx aρρτys. Thκ additiτσ τλ Zσ tτ “ρ-Mμ aρρτys was rκ‐ pτrtκd tτ imprτvκ rκsistaσθκ aμaiσst SCC Uστθiθ, Kτηκ κt aρ. whκrκ a smaρρ amτuσt τλ Zσ addκd iσtτ ““ aρρτy was λτuσd tτ rκduθκ thκ θτrrτsiτσ - rκpτrtiσμ that Zσ θaσ prτ‐ mτtκ thκ λτrmatiτσ τλ “ρ-Mμ-Zσ phasκ iσstκad τλ “ρ Mμ phasκ thκ ρattκr τλ whiθh is rκ‐ spτσsiηρκ λτr strκss θτrrτsiτσ θraθπiσμ Carrτρρ, Gτuma κt aρ. Carrτρρ, Gτuma κt aρ. . . . . Influenθe of iron Θrτσ is typiθaρρy prκsκσt as aσ impurity iσ aρρ θτmmκrθiaρ “ρ aρρτys duκ tτ thκ prτduθtiτσ prτθκss τλ “ρ aρρτys. Uσρκss spκθiλiθaρρy rκquirκd λτr spκθiaρist appρiθatiτσs, it is simpρy tττ κxpκσsivκ tτ rκmτvκ aρρ irτσ κvκσ iσ aρumiσium dκstiσκd λτr aκrτspaθκ appρiθatiτσs . Dκ‐ spitκ haviσμ a smaρρ λraθtiτσ τλ thκ θτmpτsitiτσ, irτσ is dκtrimκσtaρ tτ θτrrτsiτσ duκ tτ its ρτw sτρuηiρity aσd hκσθκ aηiρity tτ λτrm θτσstituκσt partiθρκs whiθh arκ θathτdiθ tτ thκ “ρmatrix suθh as “ρ Fκ Nisaσθiτμρu . “dditiτσaρρy, irτσ is θapaηρκ τλ sustaiσiσμ θathτdiθ rκaθtiτσs mτrκ κλλiθiκσtρy thaσ “ρ Gaρvκρκ Szπρarsπa-Smiaρτwsπa . Θσ mτrκ θτm‐ pρκx aρρτys, Fκ θaσ aρsτ θτmηiσκ with τthκr aρρτyiσμ κρκmκσts suθh as Mσ τr Cu iσ thκ ρattκr θasκ λτrmiσμ “ρ Cu Fκ , whiθh arκ aρsτ a maοτr issuκ λτr θτrrτsiτσ ”irηiρis, Cavaσauμh κt aρ. siσθκ thκ θτmηiσatiτσ τλ Fκ aσd Cu prτvidκs κvκσ μrκatκr θathτdiθ κλλiθiκσθy λτr suθh partiθρκs. Cτrrτsiτσ assτθiatκd with suθh στηρκ θathτdiθ θτσstituκσts/iσtκrmκtaρρiθs ρκads tτ

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aσ iσθrκasκ iσ ρτθaρ pH τλ thκ sτρutiτσ λurthκr κσhaσθiσμ aστdiθ dissτρutiτσ τλ thκ “ρ matrix adοaθκσt tτ say, “ρ Fκ Sκri Parπ, Paiπ κt aρ. ”irηiρis aσd ”uθhhκit “mηat, Davκσpτrt κt aρ. . . . . Influenθe of manganese Thκ additiτσ τλ Mσ is κλλκθtivκ iσ rκduθiσμ thκ pittiσμ susθκptiηiρity τλ “ρ aρρτys partiθuρarρy iσ thκ θτσtκxt τλ mτdiλyiσμ Fκ θτσtaiσiσμ iσtκrmκtaρρiθ partiθρκs Nisaσθiτμρu whκrκ Mσ θaσ suηstitutκ λτr Fκ, rκσdκriσμ thκ rκsuρtiσμ θτσstituκσt partiθρκ sτmκwhat ρκss στηρκ Thκ prκsκσθκ τλ Mσ has ηκκσ στtκd as rκduθiσμ thκ θτσθκσtratiτσ τλ Fκ aσd rκduθiσμ thκ dκμrκκ τλ rκsuρtaσt θτrrτsiτσ Kτrτρκva, Thτmpsτσ κt aρ. τwiσμ tτ thκ λτrmatiτσ τλ “ρ MσFκ has a simiρar κρκθtrτθhκmiθaρ pτtκσtiaρ with that τλ thκ “ρ matrix. Hτwκvκr, it has aρsτ ηκκσ στtκd that aσ κxθκss τλ Mσ θaσ ρκad tτ aσ iσθrκasκ iσ thκ θathτdiθ aθtivity whκσ ηκyτσd thκ sτρuηiρity ρimit sτρuηiρity τλ Mσ iσ “ρ is . wt% ª with θτσstituκσts suθh as “ρ Mσ rκadiρy λτrmiσμ Liu aσd Chκσμ . Gκσκraρρy hτwκvκr, thκ prκsκσθκ τλ Mσ θτσ‐ stituκσt partiθρκs arκ στt as dκtrimκσtaρ as partiθρκs riθh iσ Fκ τr Cu ”irηiρis aσd ”uθhhκit Cavaσauμh, ”irηiρis κt aρ. , whiθh is κvidκσθκd ηy thκ rκρiaηρκ θτrrτsiτσ pκrλτrm‐ aσθκ τλ xxx θτmmκrθiaρ “ρ aρρτy Zamiσ Sκri aσd Taμashira Tahaσi, Chaiκη κt aρ. Liu aσd Chκσμ . . . . Influenθe of lithium Thκ additiτσ τλ Li iσ “ρ aρρτys is κλλiθiκσt at siμσiλiθaσtρy rκduθiσμ aρρτy dκσsity whiρst iσ‐ θrκasiσμ strκσμth ª maπiσμ it aσ τηviτus θτσtκσdκr iσ thκ raσμκ τλ traσspτrt, σamκρy aκrτ, appρiθatiτσs. “ρ-Li aρρτys arκ a rathκr spκθiaρisκd λiκρd that spaσs thκ past λivκ dκθadκs, with dκsθriptiτσs τriμiσaρρy iσ thκ xxx sκriκs θτmpτsitiτσaρ spaθκ with priσθipaρρy Li riθh θτm‐ pτsitiτσs . Suθh sτ-θaρρκd st μκσκratiτσ “ρ-Li aρρτys wκrκ τσρy usκd iσ spκθiaρisκd appρiθa‐ tiτσs τwiσμ tτ thκir susθκptiηiρity tτ θraθπiσμ. Thκ θraθπiσμ issuκ was ρatκr maσaμκd via σκw aρρτy θτmpτsitiτσs aσd thκrmτmκθhaσiθaρ prτθκssiσμ σd μκσκratiτσ “ρ-Li aρρτys , hτwκvκr uσtiρ rκρativκρy rκθκσtρy “ρ-Li aρρτys wκrκ στt sτ pτpuρar τwiσμ tτ rκρativκρy hiμh θτrrτsiτσ ratκs aσd ρτθaρisκd λτrms τλ θτrrτsiτσ prτpaμatiτσ. Mτst rκθκσtρy, thκ rd μκσκra‐ tiτσ τλ “ρ-Li aρρτys has μaiσκd siμσiλiθaσt attκσtiτσ aσd μrτwiσμ usaμκ iσ θτmmτdity aκrτ‐ spaθκ appρiθatiτσs. Thκsκ rd μκσκratiτσ aρρτys arκ aθtuaρρy xxx sκriκs aρρτys, with ρκss Li thaσ Cu. Thκsκ σκw xxx sκriκs aρρτys wiρρ ηκ a siμσiλiθaσt aρρτy τλ thκ λuturκ, whiρst stiρρ λur‐ thκr rκsκarθh is rκquirκd λrτm a θτrrτsiτσ pκrspκθtivκ tτ λuρρy uσdκrstaσd thκ pκrλτrmaσθκ, partiθuρarρy as a λuσθtiτσ τλ thκrmτmκθhaσiθaρ trκatmκσt. Sτmκ aηridμκd iσλτrmatiτσ rκ‐ μardiσμ thκ rτρκ τλ Li upτσ θτrrτsiτσ is iσθρudκd hκrκ. Θσ Li riθh aρρτys, thκ λτrmatiτσ τλ strκσμthκσiσμ phasκ, “ρ Li whiθh is dispκrsκd hτmτμκσκτusρy thrτuμhτut thκ matrix, is rκ‐ spτσsiηρκ λτr thκ iσθrκasκ iσ strκσμth Lavκrσia aσd Graσt . Θt is hτwκvκr dκtrimκσtaρ tτ θτrrτsiτσ as “ρ Li iσitiaρρy λτrm aρτσμ thκ μraiσ ητuσdariκs. “s Li is aσ aθtivκ i.κ. ρκss στηρκ κρκmκσt, this wiρρ ρτθaρisκ dissτρutiτσ tτ Li riθh rκμiτσs aσd thκrκλτrκ susθκptiηiρity tτ attaθπ suθh as iσtκrμraσuρar θτrrτsiτσ is hiμh Martiσ . Whκσ Cu is aρsτ addκd iσ θτσοuσθtiτσ with Li iσ aρρτys suθh as ““ thκ prκθipitatiτσ τλ phasκs suθh as T “ρ CuLi τθθurs. Thκrκ arκ twτ mτdκs τλ attaθπ assτθiatκd with T , τσκ τλ whiθh T at thκ prκθipitatκ λrκκ

D”rabili“y and Corrosion of Al”mini”m and I“s Alloys: Overview, Proper“y Space, Techniq”es and Developmen“s h““p://dx.doi.org/10.5772/53752

zτσκ is dissτρvκd λτrmiσμ smaρρ pits, whiρκ thκ τthκr is whκσ T uσdκrμτ sκρκθtivκ dissτρu‐ tiτσ aρτσμ with dissτρutiτσ τλ thκ adοaθκσt “ρ matrix ρκaviσμ ρarμκr pits ”uis aσd Sθhiοvκ ”uθhhκit, Waρρ κt aρ. . . . . Influenθe of aθtivating elements i.e. Pη, Sn Lκad Pη aσd tiσ Sσ arκ usuaρρy prκsκσt iσ ρτw ρκvκρs as traθκ κρκmκσts Guσdκrsκσ, “ytaç κt aρ. Prκmκσdra, Tκrryσ κt aρ. . Whκσ prκsκσt iσ traθκ amτuσts, thκir iσλρuκσθκ is miσimaρ τr σκμρiμiηρκ. Whκσ ηy say, rκθyθρiσμ τr θτσtamiσatiτσ thκ ρκvκρs risκ aητvκ thκ sτρuηiρity ρimits, thκ prκsκσθκ τλ Pη ρκads tτ sκμrκμatiτσ that rκsuρts iσ Pη-riθh λiρm at thκ mκtaρ - τxidκ iσtκrλaθκ whκσ thκ aρρτy is hκat trκatκd at κρκvatκd tκmpκraturκ Sæviπ, Ωu κt aρ. θausiσμ thκ “ρ τxidκ λiρm tτ dκstaηiρisκ partiθuρarρy iσ thκ prκsκσθκ τλ θhρτridκ. Thκ disruptiτσ τλ “ρ τxidκ λiρm ρκads tτ aσ iσθrκasκ iσ aστdiθ rκaθtiτσ ratκ whiθh στt τσρy iσ‐ θrκasκs thκ pittiσμ susθκptiηiρity, ηut θaσ aθtivatκ thκ κσtirκ surλaθκ. This prτθκss is θaρρκd aστdiθ aθtivatiτσ, aσd has ηκκσ wκρρ dτθumκσtκd λτr a σumηκr τλ yκars ηy studiκs λrτm thκ μrτup τλ Nisaσθiτμρu Kκuτσμ, Nτrdρiκσ κt aρ. Guσdκrsκσ, “ytaç κt aρ. Ωu, Saκvρπ κt aρ. Ωu, Sæviπ κt aρ. Waρmsρκy, Sæviπ κt aρ. Ιia, Gravκr κt aρ. Gravκr, Pκdκrsκσ κt aρ. “σawati, Gravκr κt aρ. Gravκr, vaσ Hκρvττrt κt aρ. “σawati, Dipρas κt aρ. . Thκrκ havκ ηκκσ sτmκ κλλτrts tτ rκduθκ thκ aθtivatiτσ κλλκθt τλ Pη ηy ad‐ ditiτσ τλ mτrκ στηρκ aρρτyiσμ κρκmκσts suθh as Cu iσ thκ hτpκ that thκ additiτσ τλ Cu may aρtκr thκ surλaθκ pτtκσtiaρ - hκσθκ rκduθiσμ thκ aθtivatiτσ “σawati, Dipρas κt aρ. .“ simiρar rκsuρt was τηsκrvκd λτr thκ additiτσ τλ Mμ Ιia, Gravκr κt aρ. , hτwκvκr, suθh mκthτds arκ στt viaηρκ τσ thκ ηasis that thκ Pη iσtκrλκriσμ with thκ τxidκ is aσ κλλκθt iσ addi‐ tiτσ tτ aσy θhaσμκs iσ thκ aρρτy pτtκσtiaρ. Thκ prκsκσθκ τλ Sσ aρτσμ with Pη hτwκvκr rκ‐ duθκs thκ dissτρutiτσ ratκ whκσ aσσκaρκd at thκ maximum tκmpκraturκ τλ ˚C λτr aσ hτur at whiθh Sσ is λτuσd tτ dissτρvκ iσ thκ aρumiσium sτρid sτρutiτσ diρutiσμ thκ Sσ θτσθκσtra‐ tiτσ τσ thκ surλaθκ Gravκr, Pκdκrsκσ κt aρ. . . . . Influenθe of other element, inθluding Zr, Cr, Sθ, Ti, W and Sr Thκsκ κρκmκσts arκ typiθaρρy addκd iσdκpκσdκσtρy iσ smaρρ amτuσts i.κ. < . wt% λτr thκ purpτsκ τλ μraiσ rκλiσκmκσt, tτ rκduθκ rκθrystaρρisatiτσ as wκρρ as miσimisiσμ thκ κλλκθt τλ iσtκrmκtaρρiθ θτmpτuσds Vκtraστ, Hκσaμκr Ιr κt aρ. . Eρκmκσts suθh as Zr aσd Ti arκ aηρκ tτ λτrm iσtκrmκtaρρiθs at hiμh tκmpκraturκs iσ thκ “ρ mκρt, aσd pκrsist as λiσκρy dis‐ pκrsκd partiθρκs τλ “ρ Zr aσd “ρ Ti withiσ thκ sτρidiλiκd matrix, whiθh, ηasκd τσ thκir λiσκ sizκ i.κ. suθh that sτdium hydrτxidκ wiρρ dissτρvκs Siρiθatκ μρass rapidρy at tκmpκraturκ ≥ °C . Θσ additiτσ, thκ μκσκratiτσ τλ hydrτμκσ ητσds σκar thκ iσtκrλaθκ may ρκad tτ a wκaπκσiσμ τλ iσtκrλaθiaρ ητσds ηκθausκ τλ rκduθtiτσ τλ tiσ-τxidκ. Thκ rκρativκ duraηiρity τλ Ziσθ Oxidκ ap‐ pκarκd tτ ηκ duκ tτ thκ λaθt that Ziσθ τxidκ is στt rκduθκd [ ]. “ θτmmτσ τηsκrvatiτσ iσ aρρ iσvκstiμatiτσs shτws that θτrrτsiτσ θaσ ηκ miσimizκd ηy usκ τλ ρτw aρπaρi τr hiμh rκsistivity μρass, ηy iσθrκasiσμ thκ adhκsiτσ τλ thκ traσsparκσt θτσduθt‐ iσμ τxidκ tτ thκ μρass surλaθκ τr usiσμ ziσθ τxidκ rathκr thaσ tiσ-τxidκ as a traσsparκσt θτσ‐ duθtivκ θτσtaθt. Thκ usκ τλ aσti-rκλρκθtiτσ θτatκd “RC μρass is ηκiσμ usκd iσ aσ iσθrκasiσμ pκrθκσtaμκ τλ PV mτduρκs duκ tτ κxpκθtκd hiμh pτwκr κσκrμy τutput. Thκ usκ τλ “RC μρass dκθρiσκd ηκθausκ τλ thκ iσaηiρity τλ thκ θτatiσμ tτ maiσtaiσ pκrλτrmaσθκ τvκr ρτσμ pκriτd τλ timκ. Rκθκσt prτμrκss madκ has μivκσ sτmκ θτσλidκσθκ tτ thκ θτσsumκrs tτ usκ it aμaiσ. Sκvκraρ dκλκθt suθh as θτatiσμ dκμradatiτσ, sτiρiσμ aσd τptiθaρ dκμradatiτσ havκ ηκκσ τη‐ sκrvκd. Rκθκσt prτμrκss iσ “RC μρassκs has ηκκσ shτwσ ηy “RC μρass is dκvκρτpκd ηy thκ suσ pτwκr. Θt has ηκκσ shτwσ that a wκρρ-dκsiμσκd “RC θτatiσμ prτtκθtκd thκ μρass λrτm humidity aσd saσd ηρastiσμ, whκrκas thκ uσθτatκd μρass shτwκd θhippiσμs. Mτrκ thaσ thrκκ yκars τλ λiκρd data shτwκd that thκ κσκrμy μaiσ λrτm “RC siμσiλiθaσtρy κxθκκdκd ηy . tτ % τvκr uσθτatκd μρass whiθh is thκ θτσsκquκσθκ τλ thκ imprτvκd θτatiσμ μaiσs iσ diλλusκ aσd τλλ aσμρκ ρiμhts, duκ tτ κλλκθt τλ rκλraθtivκ iσdκx aσd ρiμht sθattκriσμ withiσ thκ θτatiσμ. Thκ suσ pτwκr mτduρκs arκ sρτwρy κmκrμiσμ iσ thκ marπκt. Mκtaρ κρκθtrτ miμratiτσ is a ηiμ θτσθκrσ iσ κρκθtrτσiθ iσdustry aρτσμ with θτrrτsiτσ, mτduρκ aσd disθτρτratiτσ. Thκ mκtaρ miμratiτσ rκduθκs thκ sκrviθκ ρiλκ τλ mτduρκ. S“Fρκx PS- is thκ λirst mτduρκ tτ ηκ prτduθκd tτ supprκss κρκθtrτ miμratiτσ ηy κxpρτriσμ thκ aθtivity τλ κmηκddκd κσθapsuρatiτσ whiθh prκvκσts κρκθtrτ miμratiτσ whκσ iσ θτσtaθt with mκtaρs suθh as siρvκr, θτppκr aσd σiθπκρ. Thκ λirst κσθapsuρaσt Saλρκx PS is spκθiλiθaρρy dκsiμσκd tτ prτtκθt aμaiσst mκtaρ diλλusiτσ λrτm sτρar θκρρ staθπs, adhκsivκ aσd ηus riηητσs [ ]. Whκrκas κστuμh κvidκσθκ has ηκκσ shτwσ hτw thκ advκrsκ κλλκθts τλ humidity vapτr prκs‐ surκ aσd θurrκσt ρκaπaμκs τσ thκ μρass suηstratκ thκ ηaθπ shκκt matκriaρs iσ “RC aρsτ pρay a pivτtaρ rτρκ. Θσ rκθκσt yκar hiμh mτisturκ ηarriκr aσd hiμh rκsistivity θτatiσμs τσ pτρyκthy‐ ρκσκ tκrκpthaρatκ PET havκ ηκκσ λaηriθatκd λτr appρiθatiτσ iσ PV mτduρκ ηaθπ shκκt appρi‐ θatiτσ. Θt is σκθκssary λτr thκ ηaθπ shκκt θτmpρκtκρy iσsuρatiσμ tτ prκvκσt a θτσduθtiτσ path λrτm thκ ηaθπ θτσtaθt tτ thκ μrτuσdκd mκtaρ λramκ. Tτ prκvκσt thκ pκσκtratiτσ τλ mτisturκ aσd θrκatκ ρτw watκr vapτr traσsmissiτσ ratκs WVTR, μ/m , d., θτst κλλκθtivκ θτatiσμs havκ ηκκσ θrκatκd τσ iσκxpκσsivκ pτρymκrs suθh as pτρyκthyρκσκ tκrκpthaρatκ PET aσd ηiaxiaρ τriκσtκd pτρyprτpyρκσκ ”OPP . Taηρκ shτws thκ thiθπσκss aσd traσsmissiτσ ratκs τλ vari‐ τus θτatiσμs appρiκd PET [ ].

Al”mini”m Alloys in Solar Power − Benefi“s and Limi“a“ions h““p://dx.doi.org/10.5772/54721

Material

Thickness(mm)

WVTR(g/m2d)

Tedlar/ Al/Tedlar C

0.1

NREL coa“ed PET

0.18

0.1-0.2

Tedlar / PET/ EVA (TPE)

0.2

3.0

PET

0.1

3.4

EVA

0.4-0.5

27-33

Table 4. WVTR for Polymer lamina“es a“ 37.8o and 85% Rela“ive h”midi“y

Thκsκ ηaθπ shκκts θaσ ηκ usκd as a suηstitutκ λτr μρass iλ thκy rκsist thκ iσμrκss τλ mτisturκ aσd traσspτrt τλ θurrκσt. Thκ trκatκd pτρymκr has a dramatiθ imprτvκmκσt τvκr thκ uσtrκat‐ κd pτρymκr. Thκ pκκρ strκσμth λτr diλλκrκσt ηaθπ shκκts is shτwσ iσ Taηρκ .

Material

t=0

t=1week

t=2weeks

Uncoa“ed PET

1-1.7

―

~ 0.8

NREL coa“ed PET

7-8

7.10

6.5-6.8

TPE

―

―

~4.0

Table 5. Peeling S“reng“hs

Figure 11. A cross sec“ion of a PV mod”le cons“r”c“ed wi“h an SnO2:F “ransparen“ cond”c“ing oxide(TCO) layer depos‐ i“ed on a glass s”pers“ra“e. The ac“ive semicond”c“ing layers are deposi“ed over “he “in oxide, and “he en“ire package is encaps”la“ed wi“h e“hylene vinyl ace“a“e (EVA) be“ween ano“her shee“ of glass. No“ shown are “he laser scribes “ha“ form “he individ”al solar cells connec“ed in series. Five possible c”rren“ pa“hs be“ween “he frame and “he TCO are ill”s‐ “ra“ed (1) along “he s”rface and “hro”gh “he b”lk of “he glass s”pers“ra“e, (2) along “he glass s”pers“ra“e-EVA in“er‐ face, (3) “hro”gh “he EVA b”lk,(4) along “he glass backshee“-EVA in“erface and “hro”gh “he EVA b”lk, and (5) along “he s”rface and “hro”gh “he b”lk of “he glass backshee“, and “hro”gh “he EVA b”lk [95].

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Thκ aητvκ θτatiσμ shτws μττd adhκsiτσ, wκathκr aηiρity aσd ρτw watκr vapτr traσsmissiτσ ratκs. Thκsκ θτatiσμs havκ a μττd adhκsiτσ tτ EV“ aλtκr UV τr damp hκat κxpτsurκ. Thκ amτuσt τλ watκr vapτr that diλλusκs iσtτ EV“ θτσtrτρs thκ staηiρity τλ μρass EV“ surλaθκ. Θt may that μρass/ EV“ iσtκrλaθκ λavτrs θτσdκσsatiτσ rκaθtiτσs aσd thκ hydrτρysis rκaθtiτσs arκ diλλiθuρt tτ aθhiκvκ. Thκ κxaθt mκθhaσism is στt πστwσ, hτwκvκr it is θτσλirmκd ηy rκsκarθh studiκs that humidity aσd ρκaπaμκ θurrκσt pρay a vκry prκdτmiσaσt rτρκ iσ dκμradatiτσ τλ PV mτduρκs. Thκ impτrtaσt pathways arκ shτwiσμ λiμurκ [ ]. Θσ a study H-V iσduθκs ρκaπaμκ θurrκσt λrτm κiμht mτduρκs, a pair λrτm κaθh mτduρκ typκ τλ C-Si, Pθ-Si. ”uρπ Si aσd tκσdκm οuσθtiτσ aσd muρti-οuσθtiτσ a-Si wκrκ mτσitτrκd λτr κiμht yκars. Θt was τηsκrvκd that thκ ρκaπaμκ θurrκσts λrτm C-Si Pθ-Si mτduρκ wκrκ thκrmaρ‐ ρy aθtivatκd aσd thκ aθtivatiτσ κσκrμy variκd with RH raσμiσμ λrτm . - . κv at hiμh RH tτ . κv as ρτw RH. Thκ ρκaπaμκ θurrκσts λτr a-si mτduρκs wκrκ muθh ρτwκr thaσ ηuρπ Si mτd‐ uρκs ηy a λaθtτr τλ tτ timκs. “λtκr τpκratiτσ τλ HV tκsts λτr hrs a day thκ ρτss ratκs wκrκ . % yκar λτr pL ªs, . % yκar λτr θ-s, pτsitivκ pτρarity ηκtwκκσ % as . % yκar λτr οa-si mτduρκ. Thκ ηuρπ τλ thκ mτduρκs dκμradκd θτmparκd tτ mτduρκs στt ηiasκs at HV. Fτr thiσ λiρm mτduρκs thκ ρτssκs wκrκ iσsiμσiλiθaσt. Thκ dκtaiρ τλ mτduρκs disθussκd as shτwσ iσ Taηρκ [ ]. Module type

Structure front to back

Area (m2)

Perimeter (m)

Mounls

C-Si

Glass/ C- Si cells/ Tedar

0.60

3.4

All edges frames

Pe-Si

Glass/ Pc- Si cells/ Tedar

0.52

3.1

All edges frames

2 Ja-Si

Glass/ TCO/a- Si /Al/ glass

0.76

3.7

Rear Bracke“s

3Ja- Si

Flo”ro polymer/TCO/a-Si/ SS

0.45

3.3

All edges frames

Table 6. Cons“r”c“ion and size of PV Mod”les Tes“ed

Figure 12. Fac“ors infl”encing “he d”s“ se““lemen“ [96].

Al”mini”m Alloys in Solar Power − Benefi“s and Limi“a“ions h““p://dx.doi.org/10.5772/54721

. . Importance of dust Dust is a tκrm whiθh is appρiκd tτ sτρid partiθρκ with ρκss thaσ m. Thκ maiσ sτurθκs τλ dust arκ dust ρadκσ wiσds, vτρθaσiθ κruptiτσs κtθ. Θt aρsτ iσθρudκs miθrτ pτρρκσs, miθrτλiηκr, whiθh arκ sθattκr with atmτsphκrκ. Thκ λaθtτrs iσλρuκσθκ thκ dust sκttρκmκσts arκ shτwσ iσ λiμurκ [ ]. Dust prτmτtκs dust. Θt sκttρκs iσ rκμiτσ τλ ρτw vapτr prκssurκ iσduθκd ηy thκ hiμh prκssurκ mτvκmκσts τσ iσθρiσκd /vκrtiθaρ surλaθκ. Thκ PV systκm is aλλκθtκd ηy sκvκraρ κσvirτσmκσ‐ taρ λaθtτrs as shτwσ iσ λiμurκ [ ].

Figure 13. Al“erable and ”nal“erable fac“ors de“ermining maxim”m PV sys“em yield [96].

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“mτσμst aρρ thκ κσvirτσmκσtaρ λaθtτrs rκmτvaρ τλ dust is thκ mτst θτmpρκx λaθtτrs iσ PV mτduρκ. “s rκpτrtκd iσ thκ ρitκraturκ dκμradatiτσ τλ - % iσ thκ κλλiθiκσθy τλ thκrmaρ paσ‐ κρs arκ phτtτvτρtaiθ θκρρ was rκpτrtκd λτr iσstaρρatiτσ iσ Saudi “raηia whiθh is prκvaρκσt with dκssκrt wiσd [ ]. Thκ impaθt τλ thκ dust τσ thκ rκλρκθtiτσ τλ μρass iσ shτwσ λiμurκ. Dκspitκ λκw dκvκρτpmκσts iσ surλaθκ tκθhστρτμy suθh as ρτtus surλaθκs τλ wτrπ iσ prτμram with N“S“, θρκaσiσμ ηy wκt mκthτd is stiρρ prκdτmiσaσt. Futurκ κxpρτratiτσ τσ mττσ wτuρd rκquirκ mitiμatiσμ thκ diλλiθuρtiκs pτsκd ηy Luστr rκμτ‐ ρith iσθρudκs dust. N“S“ is tasπκd with thκ dκvκρτpmκσt τλ mitiμatiτσ stratκμiκs τλ ρuσar dust. What has ηκκσ aθhiκvκd sτ λar is thκ dκvκρτpmκσt τλ aσ Eρκθtrτdyσamiθs dust shiκρd tτ miσimizκ dust aθθumuρatiτσ, a tκθhσiquκ whiθh aρsτ θτuρd ηκ usκd tτ rκmτvκ dust λrτm PVC mτduρκs. Thκ dust rκmτvaρ is aθhiκvκd ηy appρyiσμ a muρtiphasκ travκρρiσμ κρκθtriθ λiκρd tτ thκ κρκθtrτdκ that arκ κmηκddκd iσ thκ surλaθκ tτ ρiλt aσd traσspτrt θharμκd aσd uσ‐ θharμκd partiθρκs τλλ thκ surλaθκ. Fτρρτwiσμ is a ηriκλ dκsθriptiτσ τλ thκ κρκθtrτdyσamiθs dust shiκρd tκθhστρτμy ηκiσμ dκvκρτpκd ηy N“S“. “ sθhκmatiθ τλ thrκκ phasκ Eρκθtrτdyσamiθs dust shiκρd is shτwσ iσ λiμurκ [ ].

Figure 14. Schema“ic diagram of a “hree-phase Elec“rodynamic D”s“ Shield [98].

Θt θτσsists τλ a sκriκs τλ a paraρρκρ κρκθtrτdκs θτσσκθtκd tτ a muρtiphasκ “C sτurθκ that μκσ‐ κratκs a prτpaμatiσμ κρκθtrτdyσamiθs wavκ. Thκ wavκ traσspτrts thκ dust partiθρκ tτ a spκθi‐ λiκd ρτθatiτσ. “σ κρκθtriθ λiκρd is μκσκratκd ηy thκ siμσaρ τutput. Thκ strκσμth τλ κρκθtriθ λiκρd variκs prτpτrtiτσaρ tτ thκ pτtκσtiaρ diλλκrκσθκ ηκtwκκσ κρκθtrτdκs whiθh is θτσtrτρρκd ηy phasκ shiλt. Thκ uσiλτrm λiκρd θarriκs thκ θharμκd partiθρκ [ ]. N“S“ dκvκρτpκd traσsparκσt θm diamκtκr EDS Θσdium tiσ τxidκ ΘTO κρκθtrτdκs τσ a pτρyκthyρκσκ PET λiρm. Fτr tκstiσμ thrκκ κρκθtrτdκs τλ θτppκr θm Ψ θm λτr EDS wκrκ θτσstruθtκd aσd twτ τλ thκm wκrκ θτatκd with a ρτtus λiρm. “ ρτtus θτatiσμ is a twτ ρayκr systκm θτσtaiσiσμ miθrτλiρρs prτtrusiτσs ~ . mm, aσd miθrτ vaρρκys θτσtaiσiσμ κpiθutiθu‐

Al”mini”m Alloys in Solar Power − Benefi“s and Limi“a“ions h““p://dx.doi.org/10.5772/54721

ρar wax θrystaρs aσd σaστ hairs with σaστ pτrκs. Thκ twτ ρayκrκd hiκrarθhiθaρ surλaθκ is θτv‐ κrκd ηy ρτw κσκrμy θτmpτuσds with vκry ρτw surλaθκ κσκrμy ρiπκ PDMS, λρuτrτθarητσs aσd τthκr ρτw κσκrμy θτmpτuσds. Suθh a twτ ρκvκρ surλaθκ θaσ ηκ θrκatκd ηy θhκmiθaρ κtθhiσμ τr ρasκr κtθhiσμ tτ maπκ it a rτuμh surλaθκ whκrκ thκ avκraμκ μraiσ sizκ is iσ σaστ rκμiτσ. Saσdηρastiσμ aσd shτrt pκσσiσμ τr θavitatiτσ shτtρκss pκσσiσμ θaσ aρsτ ηκ usκd tτ maπκ a twτ ρκvκρ surλaθκ. Wτrπ τσ staiσρκss stκκρ has shτwσ thκ κλλκθtivκσκss τλ this prτθκss. Naστ‐ struθturκd λiρms τλ TiO wκrκ prτduθκd ηy mixiσμ tκtra-σ-ηutyρtitaσatκ,κthyρaθκtτaθκtatκ aσd κthaστρ ηy sτρ μκρ tκθhσiquκ [ ].

Figure 15. Comparison of we““ing behavior on symme“ric and asymme“ric nanos“r”c“”red s”rfaces. a, Axially symme“ric liq”id spreading of a 1μl drople“ of deionized wa“er wi“h 0.002% by vol”me of s”rfac“an“s (Tri“on X-100) deposi“ed on “ypical ver“ical nanopillars wi“h diame“ers of 500 nm, spacings of 3.5 μm and heigh“s of 10 μm(inse“).b, Unidirec“ional liq‐ ”id spreading of a drople“ on “he same dimension nanos“r”c“”res as a, b”“ wi“h a 120 deflec“ion angle(inse“). The images show “he charac“eris“ics of a spreading drople“ a“ one ins“an“ in “ime. The scale bars in “he inse“s are 10 μm [102].

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Thκ sκθrκt ρiκs iσ prκpariσμ a taiρτrκd mτrphτρτμy τλ thκ surλaθκ. Thκ surλaθκ θaσ ηκ tκx‐ turκd λτr hydrτphτηiθity watκr rκpκρρiσμ . Thκ surλaθκ κxhiηit miθrτ θτσvκxity with θρustκrs τλ σaστpartiθρκs , . Suθh surλaθκ θaσ trap a ρarμκ amτuσt τλ air whiθh has thκ aηiρity tτ iσduθκ ρarμκ wκt θτσtaθt aσμρκs λτr hydrτphτηiθity .Watκr drτps τσ suθh surλaθκs ηκ‐ θτmκ dκtaθhκd, rτρρs dτwσ aσd θarriκs thκ dust with thκm. Hτwκvκr iσ arid rκμiτσs, thκrκ is hardρy aσy raiσλaρρ λτr this phκστmκσa tτ τθθur. Supκr hydrτphτηiθ surλaθκs θaσ ηκ prκ‐ parκd τσ mκtaρs, μρassκs aσd pρastiθs. Simiρarρy a hydrτphτηiθ surλaθκ θaσ ηκ prκparκd ηy dκpτsitiσμ λiρms τλ TiO ηy hydrτρysis τλ titaσium aρτxidκs aσd hydrτρysis τλ TEOT Triκthy‐ ρτrthτtitaσatκ . Thκsκ λiρms arκ hydrτphiρiθ watκr rκpκρρiσμ aσd aρsτ rκmτvκ θτσtamiσaσts aσd miθrτηκs ηy thκ phτtτθataρytiθ rκaθtiτσ iσduθκd ηy TiO partiθρκs. Hydrτρysis aσd θτσ‐ dκσsatiτσ τλ titaσium aρτxidκ yiκρd Ti-O ηasκd σκtwτrπ. Thκ aητvκ surλaθκ τηtaiσκd is hydrτphiρiθ. Θt is aρsτ pτssiηρκ tτ θτσtrτρ thκ dirκθtiτσ τλ λρτw τλ watκr uσi-dirκθtiτσaρ τσ asymmκtriθ σaστstruθturκd surλaθκ ηy aρρτwiσμ thκ ρiquid tτ λρτw iσ τσκ dirκθtiτσ aσd piσ τσ τthκr dirκθtiτσ whiθh θaσ ηκ vκry hκρpλuρ λτr variτus μκτ‐ mκtriκs τλ phτtτvτρtaiθ mτduρκs [ ]. Fiμurκ shτws a θτmparisτσ τλ wκttiσμ ηκhaviτr τσ symmκtriθ aσd asymmκtriθ σaστstruθturκ surλaθκ [ ]. Thκ ρτtus θτatiσμs ηκiσμ wτrπκd τut ηy N“S“ is dκvκρτpκd τσ thκ priσθipρκ dκsθriηκd aητvκ. Thκ ρτtus surλaθκ dκvκρτpκd is κxpκθtκd tτ mitiμatκ dust withτut usκ τλ watκr as iσ thκ θasκ τλ hydrτphτηiθ surλaθκ. Thκ ρτtus θτatiσμ twτ ρκvκρ wτuρd shκd partiθρκs utiρiziσμ aσti θτσ‐ tamiσatiτσ aσd sκρλ θρκaσiσμ prτpκrtiκs whiθh wτuρd miσimizκ dust aθθumuρatiτσ. Suθh θτatiσμs ηasκd τσ thκ struθturκ τλ ρτtus λρτwκr suθh as hydrτphτηiθ θτatiσμs τσ μρass aσd pρastiθs wτuρd havκ thκ θapaηiρity tτ rκpκρρ dust. N“S“ is dκvκρτpiσμ ητth hydrτphτηiθ aσd hydrτphiρiθ θτatiσμs whiθh arκ σκxt μκσκratiτσ θτatiσμs tτ miσimizκ dust τσ sτρar θκρρs aσd thκrmaρ radiatiτσ. Sκρλ θρκaσiσμ aσd aσti-θτσtamiσatiτσ systκms ηκiσμ dκvκρτpκd havκ aρsτ thκ θapaηiρity tτ πiρρ ηaθtκria, θhκmiθaρ aμκσts, pathτμκσs aσd κσvirτσmκσtaρ pτρρutaσts. Θσ λuturκ thκ supκr hydrτphτηiθ θτatiσμs wτuρd pρay a ρκadiσμ rτρκ στt τσρy iσ ρuσar κσvi‐ rτσmκσt ηut aρsτ iσ sτρar θκρρs aσd mτst impτrtaσtρy iσ spaθκ κxpρτratiτσ. Thκ hyηrid θτat‐ iσμ λτr phτtτvτρtaiθ sτρar arrays arκ shτwσ iσ λiμurκ [ ]. Θσ τrdκr tτ uσdκrstaσd thκ wτrπiσμ τλ EDS, it is impτrtaσt tτ uσdκrstaσd thκ λτrθκs whiθh arκ rκspτσsiηρκ λτr ρiλtiσμ thκ saσds.Twτ typκs τλ λτrθκs arκ appρiκd ηy thκ κρκθtrτdyσamiθ λiκρd a Eρκθtrτstatiθ λτrθκ aσd η di κρκθtrτphτrκρκθtriθ λτrθκ. Mτst airητrσκ dust partiθρκs aθquirκ aσ κρκθtrτstatiθ θharμκ duriσμ thκir dκtaθhmκσt prτθκss. Eaθh saσd partiθρκ is suηοκθtκd tτ a siσusτidaρ κxθitatiτσ vτρtaμκ μκσκratκd ηy thκ κρκθtriθ λiκρd. “ θharμκ partiθρκ κxpκriκσθκd twτ λτrθκs τλ rκpuρsiτσ, τσκ taσμκσtiaρ aσd τthκr στrmaρ tτ thκ θτσtaθt aσμρκ. Thκ ρiλt λτrθκ λτr thκ partiθρκ is prτvidκd ηy θκσtriλuμaρ λτrθκ whiθh is iσduθκd ηy thκ θurviρiσκar mτtiτσ τλ thκ partiθρκ. “στthκr partiθρκ θharμκd with ªq wiρρ ηκ suηοκθtκd tτ rκpuρsivκ λτrθκ aσd it wτuρd ρκvitatκ τλ thκ ρiλtiσμ λτrθκ is ρarμκr thaσ thκ adhκ‐ siτσ λτrθκ duκ tτ thκ θumuρativκ κλλκθts τλ ρiλshitz ªvaσdκr waρρs λτrθκs, κρκθtrτstatiθ λτrθκs aσd θapiρρary λτrθκs. Thκrκ is hardρy aσy θapiρρary λτrθκ iσ thκ dκsκrt rκμiτσ. Oσ κσκrμiziσμ τλ thrκκ phasκ vτρtaμκ,thκ θharμκd partiθρκs arκ ρiλtκd λrτm thκ surλaθκ ηy thκ vκrtiθaρ θτm‐

Al”mini”m Alloys in Solar Power − Benefi“s and Limi“a“ions h““p://dx.doi.org/10.5772/54721

pτσκσt τλ thκ λiκρd aσd thκ travκρρiσμ wavκ θτmpτσκσt as mκσtiτσκd κarρiκr θarriκs thκ dust tτ thκ sθrκκσ. Siσμρκ phasκ κxθitatiτσ ρiλts thκ partiθρκs. This prτθκss ηκθτmκs mτrκ κλλκθtivκ whκσ a thrκκ phasκ vτρtaμκ is appρiκd.

Figure 16. Hybrid coa“ing for Pho“ovol“aic solar arrays [103]

“στthκr λτrθκ tτ ηκ θτσsidκrκd is diκρκθtrτphτrκtiθ λτrθκ. Θt is κxpκriκσθκd ηy θharμκd τr uσ‐ θharμκd partiθρκs iσ aσy “C τr DC λiκρd E . ”κθausκ thκ partiθρκs +q aσd ª q arκ θharμκd aσd sκparatκd ηy a distaσθκ, a dipτρκ mτmκσt qd is λτrmκd. ”κθausκ τλ iσduθκd dipτρκ mτ‐ mκσt thκsκ partiθρκs κxpκriκσθκ diκρκθtrτphτrκtiθ λτrθκ. Thκ appρiκd vτρtaμκ θrκatκs a μradi‐ κσt iσ thκ κρκθtriθ λiκρd. Thκ divκrμκσθκ τλ κρκθtriθ λiκρd appρiκs a diκρκθtrτphτrκtiθ λτrθκ Fd aσd a tτrquκ T. This λτrθκ θausκs thκ mτvκmκσt τλ σκutraρ partiθρκs τσ thκ surλaθκ aσd iσdu‐ θκs κρκθtrτstatiθ θharμiσμ ηy triητκρκθtriλiθatiτσ. This aθquirκd θharμκ wτuρd iσduθκ tτ thκ θτρumηiθ λτrθκ τλ rκpuρsiτσ tτ ρiλt thκ partiθρκs. Θσ summary, θτρumηiθ aσd diκρκθtrτphτrκtiθ λτrθκs mτvκ thκ dust partiθρκs tτ thκ surλaθκ aσd hκσθκ thκ partiθρκs aθquirκ θharμκ. Thκsκ θharμκ partiθρκs arκ rκpκρρκd ηy κρκθtrτstatiθ λτrθκs. This mκθhaσism appρiκs aρsτ tτ θτσduθtiσμ partiθρκs dκpτsitκd τσ thκ shiκρd. Thκ θharμκ q is prτpτrtiτσaρ tτ E . Partiθρκ is thκ viθiσity τλ κρκθtrτdκs aθquirκ κρκθtrτstatiθ θharμκ aσd thκy arκ rκpκρρκd whκσ thκ λτrθκ τλ rκpuρsiτσ FRκpuρsiτσ = E = E r is > λτrθκ τλ adhκsiτσ F“dhκ‐ siτσ .Thκ partiθρκ wτuρd ηκ ρiλtκd. ”y appρyiσμ a thrκκ phasκ vτρtaμκ

% τλ thκ dust is rκmτvκd iσ aητut twτ miσutκs.

Thκ κσκrμy rκquirκs λτr dust rκmτvaρ is τσρy a smaρρ λraθturκ τλ thκ κσκrμy τutput τλ thκ mτduρκsθ [ ]. Thκ κρκθtrτdκ μrid usκs iσdium tiσ τxidκ τr θarητσ σaστtuηκs. Fiμurκ shτws traσsparκσt EDS θτatiσμs iσ μρass.Thκ rτρκ τλ aρumiσium has ηκθτmκ vκry prκdτmiσaσt iσ sτρar pτwκr systκm. Thκ sτρar pτwκr systκm has ηκκσ dividκd iσ λτur distiσθt μrτups, paraητρiθ trτuμh,

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paraητρiθ dish, ρiσκar λκrsκσκρ aσd sτρar tτwκr. “ρumiσium is τσκ τλ thκ mτst impτrtaσt ma‐ tκriaρ utiρizκd iσ sτρar aηsτrηiσμ duκ tτ thκ θapaηiρity τλ its aστdiθ ρayκr λτrmκd τσ its sur‐ λaθκ ηy thκ prτθκss τλ aστdizatiτσ. Eutκθtiθ ηiσary aρumiσiumm aρρτys suθh as “ρ- wt% Ni, “ρ- wt% Cu aσd “ρ- . wt% Ca havκ ηκκσ suθθκssλuρρy usκd as aηsτrηκr ρτw rκλρκθtiτσ aσd hiμh aηsτrptiτσ .Thκ mκθhaσiθaρ aσd thκrmaρ aηiρity τλ aρumiσium aρρτys aσd rκμκσκratiτσ τλ surλaθκ is κtθhiσμ κσhaσθκs thκir prτpκrtiκs iσ sτρar pτwκr systκm. “ρumiσium κxtrusiτσ prτvidκs a θρκar κθτστmiθ advaσtaμκ iσ thκ prτduθt τλ sτρar appρiθa‐ tiτσ. Whitκ stκκρ θτsts ρκss thaσ aρumiσum τσ a dτρρar pκr pτuσd ηasis, thκ ρτwκr wκiμht τλ aρumiσium / rd τλ stκκρ aρρτw λar mτrκ matκriaρ tτ ηκ usκd at a ρτwκr θτst. ”κθausκ τλ its rκθyθρaηiρity,ρiμht wκiμht, hiμh strκσμth aσd hiμh θτrrτsiτσ rκsistaσθκ,it has ηκθτmκ a prκλκrrκd matκriaρ. ”y usiσμ aρumiσium “ρθτa is saviσμ τσ θτsts τλ sτρar pτσd aσd traσspτrtatiτσ. Hydrτ iσ Gκrmaσy is maπiσμ mirrτrs λτr θτσθκσtratκd sτρar pτwκr as wκρρ as aηsτrηκr shκκts λτr sτρar thκrmaρ appρiθatiτσ. This θτmpaσy ρauσθhκs thκ λirst taiρτrκd Hyηridρiλκ sτ‐ ρar aρumiσium aρρτy λτr θτσθκσtratκd sτρar pτwκr aσd ρauσθhκd hiμh sκρκθt θτatiσμs λτr sτρar thκrmaρ systκms. Hydrτ sκrvκs its θustτmκr iσ sτρar thκrmaρ θτσθκσtratκd sτρar pτwκr aσd phτtτvτρtaiθ λτr aρρ arκa τλ sτρar κσκrμy prτduθt. “ρi ”aηa has maσuλaθturκd KW, KW, KW aσd KW sτρar pτwκr systκms,aρumiσium ηasκd with a ρiλκ spaσ τλ yκars. “ρi”aηa.θτm . Liμht tκθhστρτμy is a ρκadiσμ aσd prτvidκs staσdard aρumiσium prτλiρκ λτr mτuσtiσμ systκms λτr sτρar κσκrμy. Paθiλiθ pτwκr maσaμκmκσt PPM has aσστuσθκd thκ iσstaρρatiτσ τλ a λτr Siκrra “ρumiσium Cτmpaσy. Θt θτσtaiσs , Mistzuηish Eρκθtriθ, aσd satθτσs ττ Kw iσvκrtτrs. Θt μκσκratκs . m Kwh pκr yκar. Θt wτuρd rκduθκ Siκrra θarητσ λττtpriσt ηy yκar pκriτd.

% aσd suppρy pτwκr tτ

Thκ usκ τλ sτρar mirrτrs θτuρd rκduθκ thκ θτst ηy saviσμ τλ miρρiτσ κurτs θτuρd ηκ madκ.

%. Fτr a

,

KW pτwκr pρaσt watts mτduρκs hτmκs τvκr a

mκμawatt pτwκr pρaσt, a

. . Conclusion “ρumiσum is pρayiσμ a prκdτmiσaσt rτρκ iσ sτρar pτwκr systκm ηκθausκ τλ its tκθhσiθaρ θa‐ paηiρity,κasκ τλ λaηriθatiτσ aσd κasκ τλ traσspτrt usκ, rκθyθρaηiρity aσd rκsistaσt tτ θτrrτsiτσ. Thκ prτmisiσμ λuturκ τλ aρumiσium iσ sτρar pτwκr is rκλρκθtκd ηy thκ prτοκθtiτσs τσ marπκt μrτwth λrτm mm tτ ηmm . ”y , thκ amτuσt θτuρd rκaθh mtτσs λrτm thκ κxist‐ iσμ mtτσs. Thκ maοτr attriηutκs arκ ρarμκ κσκrμy arκa λτr θτρρκθtiτσ, sτρar dirκθtκd iσstaρ‐ ρatiτσ aσd dyσamiθ dκvκρτpmκσt. Hτwκvκr thκrκ arκ sκvκraρ tκθhσiθaρ prτηρκms assτθiatκd with sτρar pτwκr suθh as thκ iσμrκss τλ mτisturκ θausiσμ θτrrτsiτσ aσd ρκaπaμκ τλ θurrκσt θausiσμ dκtκriτratiτσ τλ mτduρκs. Thκ watκr vapτurs iσμrκssκs thrτuμh thκ κdμκs aσd iσ‐ θrκasκs thκ θτσduθtivity τλ thκ λrτσt μρass surλaθκ aσd aρsτ thκ maμσitudκ τλ ρκaπiσμ θurrκσt. Θσ thκ λτur typκs τλ mτduρκs a . C-Si, η . PC-Si, θ . Ι a-Si Gρass/TCO/a-Si/“ρ/Gρass aσd ΙaSi Fρurτpτρymκr/TCO/a-Si/staiσρκss stκκρ , thκ twτ mτduρκs θτσtaiσiσμ a-Si shτwκd thκ

Al”mini”m Alloys in Solar Power − Benefi“s and Limi“a“ions h““p://dx.doi.org/10.5772/54721

maximum rκsistaσθκ tτ HV τpκratiτσ. Θσ HV τpκratiτσ, aρρ mτduρκs dκμradκ at ratκs hiμhκr thaσ thκ mτduρκs στt ηiasκd τσ HV. Fiρms τσ PET shτwκd prτmisiσμ prτpκrtiκs as a ηaθπ shκκt rκpρaθκmκσt λτr μρass. Thκsκ θτatiσμs κxhiηit κxθκρρκσt mτisturκ rκsistaσθκ prτpκrtiκs aσd a μττd θτhκsiτσ aλtκr κxpτsurκ tτ damp hκat. Thκ θτrrτsiτσ κλλκθt θaσ ηκ miσimizκd ηy iσθrκasiσμ adhκsiτσ τλ traσsparκσt τxidκ ηy usiσμ Ziσθ τxidκ iσ pρaθκ τλ Tiσ τxidκ aσd ηy usiσμ ρτw aθκtatκ aσd hiμh rκsistivity μρass. Dust is stiρρ hauσtiσμ thκ sθiκσtists aσd κσμiσκκrs wτrπiσμ τσ sτρar aσd spaθκ κquipmκσt. Θt is τλ vitaρ impτrtaσθκ tτ sτρar paσκρs aσd κquipmκσt usκd iσ spaθκ κxpρτratiτσ. “ suηstaσtiaρ amτuσt τλ rκsκarθh has ηκκσ dτσκ τσ κρκθtrτdyσamiθs systκm tτ rκmτvκ dust. This is θτu‐ pρκs with θrκatiσμ a ρτtus surλaθκ twτ ρκvκρ hiκrarθhiθaρ surλaθκ σaστ/miθrτ hyηrid tτ θrκ‐ atκ sκρλ θρκaσiσμ prτpκrtiκs λτr rκmτvaρ τλ dust ηy mimiθπiσμ thκ surλaθκ τλ a ρτtus λρτwκr. Variτus paiσts θτσtaiσiσμ sκρλ θρκaσiσμ aμκσts havκ aρsτ ηκκσ dκsiμσκd tτ rκmτvκ dust. Thκ wκt θhκmistry rτutκ θrκatiσμ a supκrhydrτphτηiθ surλaθκ is aσ τutstaσdiσμ aθhiκvκmκσt ηut it θaσστt ηκ appρiκd iσ dκssκrt θτσditiτσs. Θσtκσsivκ wτrπ is uσdκrtaπκσ ηy N“S“ tτ θrκatκ dust shiκρds. Θt appκar that σκw tκθhσiquκs wτuρd ηκ dκvκρτpκd tτ mitiμatκ thκ dκμradatiτσ τλ PV mτduρκs aσd thκ usκ τλ aρumiσum wτuρd θτσtiσuκ tτ risκ.

Acknowledgements Θ am hiμhρy iσdκηtκd tτ Ms. Zahra Khaσ Cτmsats aσd Ms. Tayyaηa “ηid Cτmsats λτr thκir dκdiθatκd hκρp iσ prκpariσμ thκ maσusθript τλ thκ θhaptκr λτr thκ ηττπ. Thκ aητvκ θτρ‐ ρκaμuκs havκ put iσ a vκry dκdiθatκd wτrπ iσ aρρ tκθhσiθaρ aspκθts rκρatκd tτ thκ λτrmattiσμ prτθκssiσμ aσd κditiσμ τλ this sθript.

Author details “mir Farzaσκh *, Maysam Mτhammdi , Zaπi “hmad , aσd Θσtκsar “hmad *“ddrκss aρρ θτrrκspτσdκσθκ tτ amir.λrz@μmaiρ.θτm KFUPM. Dhahraσ, Saudi “raηia Dκpt Oλ Chκmiθaρ Eσμiσκκriσμ, Cτmsats Lahτrκ, Paπistaσ Dκpt τλ Matκriaρs Eσμiσκκriσμ, Uσivκrsity τλ Taηriz, Taηriz, Θraσ Dκpartmκσt τλ Matκriaρs Eσμiσκκriσμ, Uσivκrsity τλ ”ritish Cτρumηia, Vaσθuvκr, ”.C, Caσ‐ ada Dκpartmκσt τλ Eρκθtriθaρ Eσμiσκκriσμ, Lahτrκ Cτρρκμκ Fτr Wτmκσ Uσivκrsity, Lahτrκ, Paπistaσ

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] Kaρτμirτu S“. Sτρar thκrmaρ θτρρκθtτrs aσd appρiθatiτσs. Prτμrκss iσ Eσκrμy aσd Cτmηustiτσ Sθiκσθκ - .

[

] ”κaσ ΙR., Divκr R”. Pκrλτrmaσθκ τλ thκ CPG . -KWκ dish-stirρiσμ systκm. Prτθκκd‐ iσμs τλ thκ th Θσtκrsτθiκty Eσκrμy Cτσvκrsiτσ Eσμiσκκriσμ Cτσλκrκσθκ, “uμust , - “uμust “tρaσta, G“, US“ Puηρ ηy S“E .

[

] Cτrriμaσ RD, Pκtκrsτσ TT, Ehrκsmaσ DT. Updatκ τλ thκ Sτρar Cτσθκσtratτr “d‐ vaσθκd Dκvκρτpmκσt Prτοκθt. Part τλ “κrτspaθκ Pτwκr Systκms aσd Pτwκr Cτσditiτσiσμ, “uμust , - “uμust Washiσμtτσ, DC, US“ Puηρ ηy ΘEEE .

[

] Daσμ “. Cτσθκσtratτrs “ Rκviκw. Eσκrμy Cτσvκrsiτσ aσd Maσaμκmκσt - .

.

Al”mini”m Alloys in Solar Power − Benefi“s and Limi“a“ions h““p://dx.doi.org/10.5772/54721

[

] Fκσd T, Hτλλsθhmidt ”, Ιτrμκσsκσ G, Kustκr H, Kruμκr D, Pitz-Paaρ R, κt aρ. Cτmpa‐ rativκ assκssmκσt τλ sτρar θτσθκσtratτr matκriaρs. Sτρar Eσκrμy - .

[

] Zhaτ Ι, Waσμ “, ”ρaπκrs “W, Grκκσ M“. Hiμh κλλiθiκσθy prismatiθ θτvκr siρiθτσ θτσ‐ θκσtratτr sτρar θκρρs. Twκσtiκth ΘEEE Phτtτvτρtaiθ Spκθiaρists Cτσλκrκσθκ , Sκp‐ tκmηκr , - Sκptκmηκr Las Vκμas, NV, US“ Puηρ ηy ΘEEE .

[

] Grκμτry GG, Kτshκρ RΙ. Mτdκρiσμ thκ τpκratiσμ θτσditiτσs τλ sτρar θτσθκσtratτr sys‐ tκms. Phτtτσiθs λτr Sτρar Eσκrμy Systκms, “priρ , - “priρ Strasητurμ, Fraσθκ SPΘE .

[

] Hasuiπκ H, Ωτshizawa Ω, Suzuπi “, Tamaura Ω. Study τσ dκsiμσ τλ mτρtκσ saρt sτρar rκθκivκrs λτr ηκam-dτwσ sτρar θτσθκσtratτr. Sτρar Eσκrμy - .

[

] Hκath Ι, “.R., Hτλλmaσ EL. Rκθκσt μaiσs iσ sτρar θτσθκσtratτr tκθhστρτμy. Ι.Spaθκ‐ θraλt Rτθπκts - .

[

] Hiσsθh “, Zastrτw “, Wittwκr V. Sτρ-μκρ μρassκs. “ σκw matκriaρ λτr sτρar λρuτrκs‐ θκσt pρaσar θτσθκσtratτrs? Sτρar κσκrμy matκriaρs - .

[

] Θrshid MΘ, Othmaσ MO. V-Trτuμhs with Hiμh Cτσθκσtratiτσ Ratiτs λτr Phτtτvτρtaiθ Cτσθκσtratτr Cκρρs. Sτρar Cκρρs - .

[

] Θsshiπi N, Wataσaηκ H, Shishidτ K, Ohtτmτ M, Wataσaηκ K. Studiκs τσ sτρar-dish hκatκd stirρiσμ κσμiσκs TNT- , N“S- . Prτθκκdiσμs τλ thκ th Θσtκrsτθiκty Eσκrμy Cτσvκrsiτσ Eσμiσκκriσμ Cτσλκrκσθκ, “uμust , - “uμust “tρaσta, G“, US“ Puηρ ηy S“E .

[

] Kriηus “, Huρκihiρ M, Timiσμκr “, ”κσ-Mair R. Pκrλτrmaσθκ τλ a rκθtaσμuρar sκθτσ‐ dary θτσθκσtratτr with aσ asymmκtriθ hκρiτstat λiκρd. Sτρar Eσκrμy - .

[

] Li M, Waσμ LL. Θσvκstiμatiτσ τλ κvaθuatκd tuηκ hκatκd ηy sτρar trτuμh θτσθκσtratiσμ systκm. Eσκrμy Cτσvκrsiτσ aσd Maσaμκmκσt .

[

] Maish “”. PV Cτσθκσtratτr “rray Fiκρd Pκrλτrmaσθκ Mκasurκmκσt.Sτρar Cκρρs - .

[

] Mτrκρ DE, “yκrs SR, Guρiστ D“, Tκσσysτσ RC, Eμμκr R“. Sτρar Cτσθκσtartτr Matκ‐ riaρs Dκvκρτpmκσt. st Θσtκrsτθiκty Eσκrμy Cτσvκrsiτσ Eσμiσκκriσμ Cτσλκrκσθκ “dvaσθiσμ tτward Tκθhστρτμy ”rκaπτut iσ Eσκrμy Cτσvκrsiτσ. Saσ Diκμτ, C“, US“ “CS .

[

] Paρavras Θ, ”aπτs GC. Dκvκρτpmκσt τλ a ρτw-θτst dish sτρar θτσθκσtratτr aσd its ap‐ pρiθatiτσ iσ zκτρitκ dκsτrptiτσ. Rκσκwaηρκ Eσκrμy - .

[

] Rτwaσ ”, Mθ Cτrmaθπ S, Dτraσ Ι, Nτrtτσ ”. Quaσtum dτt sτρar θτσθκσtratτrs “σ iσvκstiμatiτσ τλ variτus μκτmκtriκs. Hiμh aσd Lτw Cτσθκσtratiτσ λτr Sτρar Eρκθtriθ “ppρiθatiτσs ΘΘ, “uμust , - “uμust Saσ Diκμτ, C“, Uσitκd statκs SPΘE .

353

354

Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

[

] Siσμh P, Liηurdy Ι“. Sτρar θτσθκσtratτr dκsiμσ λτr uσiλτrm λρux τσ a λρat rκθκivκr. Eσ‐ κrμy Cτσvκrsiτσ aσd Maσaμκmκσt - .

[

] Tκθpτyτtρ-Tτrrκs M, Campτs-“ρvarκz Ι, Tκρρκz-“ρaσis F, Esθτηκdτ-“ρatτrrκ Ι, “μui‐ ρar ΙQ, Saσθhκz-Mτσdraμτσ Ι. RF θτσtrτρ systκm τλ a paraητρiθ sτρar θτσθκσtratτr. Hiμh aσd Lτw Cτσθκσtratiτσ λτr Sτρar Eρκθtriθ “ppρiθatiτσs ΘΘ, “uμust , - “u‐ μust Saσ Diκμτ, C“, Uσitκd statκs SPΘE .

[

] Vaρadκ FH. Sτρar θτσθκσtratτr advaσθκd dκvκρτpmκσt prτμram updatκ. Prτθκκdiσμs τλ thκ rd Θσtκrsτθiκty Eσκrμy Cτσvκrsiτσ Eσμiσκκriσμ Cτσλκrκσθκ, Ιuρy , “uμust Dκσvκr, CO, US“ Puηρ ηy ΘEEE .

[

] Wτσμ W“, Gκσμ SM, Castρκ CH, Maθτsπτ RP. Dκsiμσ, λaηriθatiτσ aσd tκst τλ a hiμh κλλiθiκσθy rκλraθtivκ sκθτσdary θτσθκσtratτr λτr sτρar appρiθatiτσs. th Θσtκsτθiκty Eσκrμy Cτσvκrsiτσ Eσμiσκκriσμ Cτσλκrκσθκ, Ιuρy , - Ιuρy Las Vκμas, N“, US“ ΘEEE .

[

] Hτρηκrt KE, Havκrπamp CΙ. Θmpaθt τλ sτρar thκrmaρ pτwκr pρaσts τσ watκr rκsτurθκs aσd κρκθtriθity θτsts iσ thκ Sτuthwκst. st Nτrth “mκriθaσ Pτwκr Sympτsium, N“PS , Oθtτηκr , - Oθtτηκr Starπviρρκ, MS, Uσitκd statκs ΘEEE Cτmputκr Sτθiκty .

[

] Ortiz-Rivκra E, Fκρiθiaστ-Cruz L. Pκrλτrmaσθκ κvaρuatiτσ aσd simuρatiτσ τλ a Sτρar Thκrmaρ Pτwκr Pρaσt. ΘEEE Eσκrμy Cτσvκrsiτσ Cτσμrκss aσd Expτsitiτσ, ECCE , Sκptκmηκr , - Sκptκmηκr Saσ Ιτsκ, C“, Uσitκd statκs ΘEEE Cτmputκr Sτθiκty .

[

] Camηrτσκrτ LEG, Caσadas Θ, Martiσκz D, Ruiz-Rτmaσ Ι. Fτamiσμ τλ aρumiσium-siρi‐ θτσ aρρτy usiσμ θτσθκσtratκd sτρar κσκrμy. Sτρar Eσκrμy - .

[

] Fρamaσt G, Fκrriκrκ “, Lapρazκ D, Mτσty C. Sτρar prτθκssiσμ τλ matκriaρs τppτrtuσi‐ tiκs aσd σκw λrτσtiκrs. Sτρar Eσκrμy - .

[

] Martiσκz D, Rτdriμuκz Ι. Matκriaρs surλaθκ trκatmκσts ηy θτσθκσtratκd sτρar ρiμht “ rκσκwaηρκ κσκrμy τptiτσ Tratamiκσtτ supκrλiθiaρ dκ matκriaρκs mκdiaσtκ ρuz sτρar θτσθκσtrada uσa τpθiτσ mκdiaσtκ κσκrμias rκστvaηρκs. Rκvista dκ Mκtaρurμia Ma‐ drid - .

[

] ”aπτs Ι, Miyamτtτ HK. Sτρar hydrτμκσ prτduθtiτσ - Rκσκwaηρκ hydrτμκσ prτduθ‐ tiτσ ηy dry λuκρ rκλτrmiσμ. Sτρar Hydrτμκσ aσd Naστtκθhστρτμy, “uμust , “uμust Saσ Diκμτ, C“, Uσitκd statκs SPΘE .

[

] ”ayπara SZ. Hydrτμκσ prτduθtiτσ ηy dirκθt sτρar thκrmaρ dκθτmpτsitiτσ τλ watκr, pτssiηiρitiκs λτr imprτvκmκσt τλ prτθκss κλλiθiκσθy. Θσt Ι Hydrτμκσ Eσκrμy - .

[

] Mτri M, Kaμawa H, Naμayama H, Saitτ Ω. Currκσt status τλ study τσ hydrτμκσ prτ‐ duθtiτσ with spaθκ sτρar pτwκr systκms SSPS . th Θσtκrσatiτσaρ Cτσλκrκσθκ τσ Sτ‐ ρar Pτwκr λrτm Spaθκ, SPS ' - Tτμκthκr with Thκ th Θσtκrσatiτσaρ Cτσλκrκσθκ τσ

Al”mini”m Alloys in Solar Power − Benefi“s and Limi“a“ions h““p://dx.doi.org/10.5772/54721

Wirκρκss Pτwκr Traσsmissiτσ, WPT , Ιuσκ Eurτpκaσ Spaθκ “μκσθy .

,

- Ιuρy

Graσada, Spaiσ

[

] Rτmaσ R, Caσadas Θ, Rτdriμuκz Ι, Hκrσaσdκz MT, Gτσzaρκz M. Sτρar siσtκriσμ τλ aρumiσa θκramiθs Miθrτstruθturaρ dκvκρτpmκσt. Sτρar Eσκrμy .

[

] ”rκσσa M, Fτiadκρρi F, Rτsθia M, Zaσiσκρρi D. Evaρuatiτσ τλ sτρar θτρρκθtτr pρaσt tτ θτσtriηutκ θρimatκ θhaσμκ mitiμatiτσ. ΘEEE Θσtκrσatiτσaρ Cτσλκrκσθκ τσ Sustaiσ‐ aηρκ Eσκrμy Tκθhστρτμiκs, ΘCSET , Nτvκmηκr , - Nτvκmηκr Siσ‐ μapτrκ, Siσμapτrκ Θσst. τλ Eρκθ. aσd Eρκθ. Eσμ. Cτmputκr Sτθiκty .

[

] Rτσσκρid M, “dstκσ M, Liσdstrτm T, Nτstκρρ P, Waθπκρμard E. Optiθaρ sθattκriσμ λrτm rτuμh-rτρρκd aρumiσium surλaθκs. “ppρ.Opt. - .

[

] Maθhiσda GT, Chτwdhury S, “rsθτtt R, Chτwdhury SP, Kiηaara S. Cτσθκσtratiσμ sτρar thκrmaρ pτwκr tκθhστρτμiκs “ rκviκw. “σσuaρ ΘEEE Θσdia Cτσλκrκσθκ Eσ‐ μiσκκriσμ Sustaiσaηρκ Sτρutiτσs, ΘNDΘCON, Dκθκmηκr , - Dκθκmηκr Hydκraηad, Θσdia ΘEEE Cτmputκr Sτθiκty .

[

] ΘE“. Tκθhστρτμy rτadmap ª θτσθκσtratiσμ sτρar pτwκr.

[

] ”ödκπκr ΙM, ”auκr M, Pκhσt M. “ρumiσium aσd Rκσκwaηρκ Eσκrμy Systκms ª Prτs‐ pκθts λτr thκ Sustaiσaηρκ Gκσκratiτσ τλ Eρκθtriθity aσd Hκat. .

[

] Mτπ SC. “ρumiσium κθτστmy λτr sustaiσaηρκ dκvκρτpmκσt “ρumiσium as θτrκ ma‐ tκriaρ λτr κσκrμy stτraμκ aσd κσκrμy saviσμ prτduθts Lτw θτst, hiμh pκrλτrmaσθκ, aσd κasy prτθκssiσμ iσ dκvκρτpiσμ θτuσtriκs. ΘEEE Gρτηaρ Humaσitariaσ Tκθh‐ στρτμy Cτσλκrκσθκ, GHTC , Oθtτηκr , - Nτvκmηκr Sκattρκ, W“, Uσitκd statκs ΘEEE Cτmputκr Sτθiκty .

[

] Fκσd T, Ιτrμκσsκσ G, Kuκstκr H. “ppρiθaηiρity τλ hiμhρy rκλρκθtivκ aρumiσium θτiρ λτr sτρar θτσθκσtratτrs. Sτρar Eσκrμy - .

[

] Graσqvist CG. Radiativκ Hκatiσμ aσd Cττρiσμ with Spκθtraρρy Sκρκθtivκ Surλaθκs. “ppρ.Opt. - .

[

] Kκρρκr F, Huσtκr MS, Rτηiσsτσ DL. Struθturaρ λκaturκs τλ τxidκ θτatiσμs τσ aρumiσi‐ um. Eρκθtrτθhκmiθaρ Sτθiκty -- Ιτurσaρ - .

[

] Hκσρκy V. “στdiθ Oxidatiτσ τλ “ρumiσium aσd its “ρρτys. Pκrμamτσ Prκss

[

] Wττdmaσ TP. Liμht Sθattκriσμ iσ Pτrτus “στdiθ “ρumiσium Oxidκ Fiρms- . Cτρτur Eλλκθts. Thiσ Sτρid Fiρms .

[

] Wττdmaσ TP. Liμht Sθattκriσμ iσ Pτrτus “στdiθ “ρumiσium Oxidκ Fiρms - . Pτρari‐ zatiτσ Eλλκθts. Thiσ Fiρms - .

[

] Pavρτviθ T, Θμσatiκv “. Optiθaρ “σd Miθrτstruθturaρ Prτpκrtiκs τλ “στdiθaρρy Oxi‐ dizκd “ρumiσium. Thiσ Sτρid Fiρms .

.

.

355

356

Al”mini”m Alloys - New Trends in Fabrica“ion and Applica“ions

[

] Pavρτviθ T, Θμσatiκv “. Optiθaρ Prτpκrtiκs τλ Spκθtraρρy-Sκρκθtivκ, “στdiθaρρy-Cτatκd, Eρκθtrτρytiθaρρy-Cτρτrκd “ρumiσium Surλaθκs. Sτρar κσκrμy matκriaρs - .

[

] Graσqvist C. Optiθaρ prτpκrtiκs τλ iσtκμraρρy θτρτrκd aστdiθ τxidκ λiρms τσ aρumiσi‐ um. Ιτurσaρ τλ “ppρiκd Physiθs - .

[

] Kumar SN, Maρhτtra LK, Chτpra KL. Niθπκρ Piμmκσtκd “στdizκd “ρumiσium as Sτ‐ ρar Sκρκθtivκ “ηsτrηκrs. Sτρar κσκrμy matκriaρs - .

[

] Cτdy GD, Stκphκσs R”. Optiθaρ Prτpκrtiκs τλ a Miθrτsθτpiθaρρy Tκxturκd Surλaθκ. - .

[

] Chaσμ V, ”τρsaitis P. Study τλ Twτ ”iσary Eutκθtiθ “ρumiσium “ρρτys as Sκρκθtivκ “ηsτrηκrs λτr Sτaρr Phτtτthκrmaρ Cτσvκrsiτσ. Sτρar κσκrμy matκriaρs .

[

] Pκρρκμriσi G, ”ruμhκra P, Quazzτ F. Oσ thκ Prτpκrtiκs τλ thκ Supκrpρastiθ “ρumiσi‐ um-Caρθium “ρρτy as Matκriaρ λτr Sτρar Cτρρκθtτrs. Sτρar κσκrμy matκriaρs - .

[

] Parida ”, Θσiyaσ S, Gτiθ R. “ rκviκw τλ sτρar phτtτvτρtaiθ tκθhστρτμiκs. Rκσκwaηρκ aσd Sustaiσaηρκ Eσκrμy Rκviκws - .

[

] Wurλκρ P. Thκrmτdyσamiθ ρimitatiτσs tτ sτρar κσκrμy θτσvκrsiτσ. Eρsκviκr

[

] Fκρtriσ “, Frκuσdρiθh “. Matκriaρ θτσsidκratiτσs λτr tκrawatt ρκvκρ dκpρτymκσt τλ phτtτvτρtaiθs. Rκσκwaηρκ Eσκrμy - .

[

] Duraσ Sahiσ “, Diσθκr Θ, Rτsκσ M“. Thκrmτdyσamiθ aσaρysis τλ sτρar phτtτvτρtaiθ θκρρ systκms. Sτρar Eσκrμy Matκr.Sτρar Cκρρs - .

[

] ”rτwσ GF, Wu Ι. Third μκσκratiτσ phτtτvτρtaiθs. Lasκr aσd Phτtτσiθs Rκviκws .

[

] Miyashita N, Shimizu Ω, Kτηayashi N, Oπada Ω, Ωamaμuθhi M. Faηriθatiτσ τλ GaΘσ‐ N“s-ηasκd sτρar θκρρs λτr appρiθatiτσ tτ muρti-οuσθtiτσ taσdκm sτρar θκρρs. ΘEEE th Wτrρd Cτσλκrκσθκ τσ Phτtτvτρtaiθ Eσκrμy Cτσvκrsiτσ, WCPEC- , May , May Waiπτρτa, HΘ, Uσitκd statκs Θσst. τλ Eρκθ. aσd Eρκθ. Eσμ. Cτmputκr Sτ‐ θiκty .

[

] Grκκσ M“. Thiσ-λiρm sτρar θκρρs Rκviκw τλ matκriaρs, tκθhστρτμiκs aσd θτmmκrθiaρ status. Prτθκκdiσμs τλ thκ Θσtκrσatiτσaρ Cτσλκrκσθκ τσ Optiθaρ aσd Optτκρκθtrτσiθ Prτpκrtiκs τλ Matκriaρs aσd “ppρiθatiτσs ΘCOOPM“ Spriσμκr Strκκt, Nκw Ωτrπ, , Uσitκd Statκs Spriσμκr Nκw Ωτrπ LLC .

[

] Rκy-Stτρρκ Θ, Garθia Θ, Gaρiaσa ”, “ρμτra C. Θmprτvκmκσts iσ thκ MOVPE μrτwth τλ muρti-οuσθtiτσ sτρar θκρρs λτr vκry hiμh θτσθκσtratiτσ. Ι.Cryst.Grτwth - .

[

] Cτσiηκκr G, Li Ω, Sρaτui “, Taτ M, Tτpiθ M. “dvaσθκd iστrμaσiθ matκriaρs aσd θτσ‐ θκpts λτr phτtτvτρtaiθs. Eσκrμy Prτθκdia v-.

.

Al”mini”m Alloys in Solar Power − Benefi“s and Limi“a“ions h““p://dx.doi.org/10.5772/54721

[

] ”τsi M, Pκρτsi C. Thκ pτtκσtiaρ τλ ΘΘΘ-V sκmiθτσduθtτrs as tκrrκstriaρ phτtτvτρtaiθ dκ‐ viθκs. Prτμ Phτtτvτρtaiθs Rκs “ppρ - .

[

] Ιaμκr-Waρdau “. Eurτpκaσ Phτtτvτρtaiθs iσ wτrρd widκ θτmparisτσ. Ι.Nτσ Cryst.Sτρids - .

[

] Tοτtta S. “dvaσtaμκs τλ κxtrudκd aρumiσium iσ sτρar pτwκr μκσκratiτσ systκms prτθ‐ κssκs. “dvaσθκd Matκriaρs aσd Prτθκssκs - .

[

] Wκrσκr C. “ρumiσium κxtrusiτσ iσ sτρar pτwκr appρiθatiτσs. Liμht mκtaρ “μκ “uμust - .

[

] G.E. Cτhκσ, D.W. Kκatσκy aσd G.Ι. Kτρη, Fiσaρ rκpτrt τσ Opκratiτσ aσd Maiσtκ‐ σaσθκ Θmprτvκmκσt Prτμram λτr Cτσθκσtratiσμ Sτρar Pτwκr Pρaσts€ Saσdia ρaη rκ‐ pτrt CSPS“ND, .

[

] Paraητρiθ Trτuμh Wτrπshτp Cττρiσμ λτr Paraητρa Trτuμh Pτwκr Pρaσts, DOE prκ‐ sκσtatiτσ, NREL, PRr,“uμust - , , Oσtriτ .

[

] Zaπi “hmad aσd M. “hsaσ, Naστ-paiσts λτr Dκsκrt Eσvirτσmκσt, οr τλ xyz τr “CE, Nτv

[

] Ωτσμxiaσμ Li, Ιurμκσ Haμκσ, Wiσλriκd Sθhaλλrath, Pκtκr Ostrθhiπ, Diκρκt Harry Sτρar Eσκrμy Matκriaρs aσd Sτρar Cκρρs, [ - ]

[

] Haσs Ι, Eσsiπat, Ditsθhκ-Kuru P, Nκiσhuis C, ”arthρτtt W. Supκrhydrτphτηiθity iσ pκrλκθtiτσ thκ τutstaσdiσμ prτpκrtiκs τλ thκ ρτtus ρκaλ. ”κiρstκiσ Ιτurσaρ τλ Naστtκθh‐ στρτμy , ª .

[

] Marπ Ι. Hyatt, Shariσ “. Starπa, Dust Maσaμκmκσt Prτοκθt “dvaσθκ Capaηiρitiκs prτοκθt τλλiθκ, ηrττπpτrt Rd, Gρκσσ rκsκarθh Cκσtrκ at ρκwis λiκρds, Cρκvκρaσd, OH US“, .

[

] R.N Wκσz, Rκsistaσθκ tτ sτρid surλaθκ tτ wκttiσμ ηy wκar, Θσd Eσμ. Chκm vτρ ,

[

] Ωτσμxiaσμ Li, Ιurμκσ Haμκ, Wiσλriκd Sθhaλλartμ,Pκtκr OOtsθhiπ,Diκtκr, Harκr, Titaσi‐ um Diτxidκ Fiρms Fτr Phτtτvτρtaiθ Cκρρs Dκrivκd Frτm Sτρ Gκρ Prτθκssκs,Sτρar Eσκr‐ μy Matκriaρs “σd Sτaρr Cκρρs, , ,paμκ στ .

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