基于临界晶胚法的Ni固液界面能分子动力学计算  

Molecular Dynamics Calculation of Crystal-Melt Interfacial Free Energy of Ni by the Critical Nucleus Method

作　　者：周化光[1] 王猛 林鑫[1] 黄卫东[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属材料与工程》2013年第6期1205-1209,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50901061和50971102);国家重点基础研究发展计划"973"(2011CB610402);高等学校学科创新引智计划(08040);西北工业大学凝固技术国家重点实验室基金(02-TZ-2008)

摘　　要：使用分子动力学法,研究不同半径的Ni晶胚在其液相中的生长及熔化行为。研究发现,一定半径的晶胚存在临界形核温度,高于这个温度,晶胚生长;低于这个温度,晶胚熔化,并且临界形核温度与晶胚半径的倒数成线性关系,这和经典形核理论以及Gibbs-Thomson模型的描述一致。基于临界晶胚演化的分子动力学模拟方法得到了金属Ni的Gibbs-Thomson系数为1.56×10-7K·m,并获得了Ni的固液界面能为0.211J/m2,结果与实验测量值一致。The growth and melting of nuclei with different radii in liquid Ni have been investigated by molecular dynamics simulation. The result shows that a critical nucleus is not stable and will either grow or melt at certain undercooling temperature. By calculating the upper limit of the growth temperature and the lower limit of the melt temperature, the critical nucleation temperatures for different nucleus radii can be determined, which has a linear relationship with the inverse of the nucleus radius, in accordance with classical nucleation theory and Gibbs-Thomson model. The Gibbs-Thomson coefficient of 1.56×10 -7 K·m and the crystal-melt interfacial free energy of 0.211 J/m2 are obtained based on the molecular dynamics simulation of critical nucleus evolution for Ni system, consistent with the experimental results.

关 键 词：临界晶胚 分子动力学 固液界面能 经典形核理论 

分 类 号：TG111.4[金属学及工艺—物理冶金]