(6.2)--Electrodeposited Al–Mn alloys wi机械工程材料机械工程材料.pdf

Availableonlineat

ActaMaterialia57(2009)3810–3822

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ElectrodepositedAl–Mnalloyswithmicrocrystalline,

nanocrystalline,amorphousandnano-quasicrystallinestructures

ShiyunRuan,ChristopherA.Schuh*

DepartmentofMaterialsScienceandEngineering,MassachusettsInstituteofTechnology,77MassachusettsAvenue,Cambridge,MA02139,USA

Received10March2009;accepted19April2009

Availableonline21May2009

Abstract

Al–MnalloyswithMncontentrangingfrom0to15.8at.%arepreparedbyelectrodepositionfromanionicliquidatroomtemper-

ature,andexhibitaremarkablybroadrangeofstructures.Thealloysarecharacterizedthroughacombinationoftechniques,including

X-raydiffraction,electronmicroscopyandcalorimetry.ForalloyswithMncontentupto7.5at.%,increasingMnadditionsleadtoa

decreaseingrainsizeofsingle-phasemicrocrystallineface-centeredcubic(fcc)Al(Mn).Between8.2and12.3at.%Mn,anamorphous

phaseappears,accompaniedbyadramaticreductioninthesizeofthecoexistingfcccrystallitestothe2–50nmlevel.AthigherMn

contents,thestructurenominallyappearsentirelyamorphous,butisshowntocontainorderintheformofpre-existingnucleiofthe

icosahedralquasicrystallinephase.Additionally,nanoindentationtestsrevealthatthenanostructuredandamorphousspecimenshave

veryhighhardnessesthatexhibitcomplextrendswithMncontent.

2009ActaMaterialiaInc.PublishedbyElsevierLtd.Allrightsreserved.

Keywords:Electrodeposition;Aluminumalloys;Nanocrystalline;Quasicrystals;