嵌入纳米Fe颗粒的Fe液凝固过程的分子动力学模拟.pdf

《嵌入纳米Fe颗粒的Fe液凝固过程的分子动力学模拟.pdf》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、物理化学学~E(WuliHuaxueXuebao1FebruaryActa咖．一Chim．，z．2013，29(2)，245—249245[Article】doi：10．3866／PKU．WHXB201212251www．whxb．pku．edu．cn嵌入纳米Fe颗粒的Fe液凝固过程的分子动力学模拟吴永全沈通陆秀明张宁赖莉珊高帅(上海大学材料科学与工程学院，上海市现代冶金及材料制备重点实验室，上海200072)摘要：采用Sutton—Chen势函数及分子动力学(MD)方法对嵌入了Fe纳米团簇(半径从0

2、．4—1．8nm)的Fe液凝固过程进行了模拟．模拟结果表明只有当嵌入的纳米团簇半径超过0．82nm才能降低凝固时所需要的临界过冷度(AT)，起到诱导凝固的作用．同时采用原子键型指数法(CTJM-2)对样本在凝固过程中的原子结构进行了标定，通过观察微观结构演变发现当嵌入纳米团簇能够作为凝固核心时，体系按照hcp-fcc交叉形核的方式长大．同时还发现嵌入纳米团簇对体系凝固过程晶核的生长方向及凝固的最终构型存在“结构遗传效应”．关键词：Fe纳米团簇；过冷度：凝固过程：微观结构演化：分子动力学中图分类号：O6

3、41：0642；TF01SolidificationofLiquidFewithEmbeddedHomogeneousSolidFeNanopartiCleSfromMolecularDynamicsSimulationsWUYong—QuanSHENTongLUXiu—MingZHANGNingLAILi—ShanGAOShuarShanghaiKeyLaboratoryofModernMetallurgy＆MaterialsProcessing,SchoolofMaterialsSciencean

4、dEngineering,ShanghaiUniversity,Shanghai200072，R．China)Abstract：SolidificationprocessesofliquidFewithembeddedhomogeneoussolidnanopa~iclewithradiusrangingfrom04to1．8nmwerestudiedbymoleculardynamics(MD)simulationadoptingtheSutton．Chenpotentia1．1twasfoundt

5、hattheparticleswhoseradiiexceed0．82nmcouldobviouslydecreaselhecriticalundercooling(△7_)andinducesolidification．Themicrostructuralevolutionduringthesolidificationprocesswastracedthroughlheatomdefinitionwithcluster-typeindexmethod(CTlM-2)．Resultsrevealedt

6、hatwhentheembeddedparticleinducedsolidification，thegrowthprocessofnucleuswouldproceedasacross—nucleationbetweenhcpandfccstructures．alittlesimilarl0thecutecticcrvstallizationprocess．Moreover,theheredityeffectattributedbyembeddedsolidnanoparticlewasclearl

7、yobsewedduringthemicrostructuralevolution．KeyWords：SolidFenanopa~icle；Undercooling；Solidificationprocess；MicrostructuralevolutionMoleculardynamicssimulation1Introductionprocesses．Atdeepundercooling，solidificationprocessusuallyThemacro-propertiesofmetall

8、icmaterialsaremainlydeter-takesplacebythehomogeneousnucleationifimpuritiesareex-minedbytheirmicrostructureswhicharemainlyaffectedbycluded．～However,inmanycases，thesolidificationstartstheoriginalconfigurationsinliquidstateandthesol