Ni64Al21V15沉淀过程DO22向L10（M=1）结构转变的微观相场模拟（英文）.pdf

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1、RareMetalMaterialsandEngineeringAvailableonlineatwww．sciencedirect．comVolume42。Issue6，June2013OnlineEnglisheditionoftheChineselanguagejourna蛳ScienceDirectCitethisarticleas：RareMetalMaterialsandEngineering，2013，42(6)：1113-1117MicroscopicPhase--FieldSimulationoftheStructureTransformationfromD022

2、toLlo(M=I)PhaseinNis4AI21V1sAlloyChangXiuli，WangYongxin，ChenZheng，ZhangJing，ChengLiweiStateKeyLaboratoryofSolidificationProcessing，NorthwesternPolytechnicalUniversity,Xi'an710072,ChinaAbstract：ThestructuretransformationfromDO22toL10(^仁1)phaseinNi64A121V15alloyat1150Kwasstudiedbythemicro—scopic

3、phase—fieldkineticmode1．TheresultsshowthatL10(朋l-1)structureprecipitatesatinterphaseduringthemiddlestageoftheagingprocesswiththreetypesoftheformationmechanism．Firstly，theL10(1)structurewhichalignsalong【001]directionandnucleatesattheinterphaseofL12andDO22growstowardsD022phase．Secondly，theL10(1)

4、structurewhichalignsalong【001】directionnucleatesat90。ordereddomainboundaryofDO22phaseandexpandstothe[001]directionofDO22phase．Thirdly，theL10(^仁1)structurewhichalignsalong[100]directionnucleatesattheinterphaseoftwo[100]alignedDO22structure，andexpandstowardsDO22phase．ThephasetransformationfromDO

5、22structuretoL10(仁1)structureisaccomplishedbyatomicdiffusion．InaperfectDO22phase，thesiteismainlyoccupiedbyVatoms，whilethet22anda3sitesbyNiatomsandthealsitebyA1atoms．Astheagingprocessproceeds，Vatomswhichmigrateto0[2site，leadingtotheatomicorderingon(002)planetakestheplaceofbothanda2sitesultimate

6、ly，andtheNiatomsmigratefroma2to／21siteandoccupyboth121and／23siteslastly，whileA1atomsdiffuseto—wardsoutsideofDO22structurefacilitatingtheformationofhighlyorderedLlo(仁1)structurefinally．Keywords：structuretransformation；L10(1)structure；orderparameter；Ni—A1-Valloy；microscopicphase—fieldmodelAsanim

7、portantaviationstructuremateria1．theNi—A1．Va1．systemtendingtoward【jJ．ThisshowstheDO，，structurewill1oyexhibitsmuchoutstandinghightemperatureperformanceeventuallyexistindifferentformswithdiferentconditions．attributingtoitsspecificinternal