分子动力学方法模拟Be高温和高压的状态方程和力学性质  

Study of equations of state and mechanical property of Be by molecular dynamics method

作　　者：黄晓玉[1] 何朝政[1] 宋海珍[1] 殷复荣[1] 于荣梅[1] 

机构地区：[1]南阳师范学院物理与电子工程学院,河南南阳473061

出　　处：《西南民族大学学报（自然科学版）》2014年第6期921-927,共7页Journal of Southwest Minzu University(Natural Science Edition)

基　　金：国家自然科学基金青年科学基金(批准号:11304167);河南省教师教育改革重点项目(批准号:2013-JSJYZD-053);南阳师范学院科研基金(批准号:ZX2013020;ZX2014088)

摘　　要：利用分子动力学方法,采用修正镶嵌原子势函数,在两组势参数下模拟Be单晶的等温、等压状态方程.通过径向分布函数,均方根位移随时间的变化分析Be的结构信息.比较两组参数的模拟结果,第一组势参数作用下体系原子间作用较小,较易压缩.两组势参数300K等温压率比较,第二组势参数的模拟结果与实验符合的更好.对于弹性常数,第二组势参数不能考虑温度和压强的影响.用第一组势参数计算Be单晶的弹性常数,根据弹性常数随压强的变化判断材料的低温相变,相变压强为320GPa,与第一性原理计算符合较好;弹性常数随温度增加而减小,与实验结果相符.总体而言,第一组势函数能更全面的反映Be单晶的结构特点.Beryllium is an important strategic nuclear material, which was used in weapons system, atomic energy, aerospace fields. Based on these applying requirements, study of beryllium on structure and properties was necessary. This paper uses molecular dynamics method and modified embedded atom potential to study equations of state of beryllium under high temperature and high pressure with two sets of potential parameters. Structure information of beryllium was analyzed by the radial distribution function and mean square displacement. To compare the computer simulation results with two sets of potential parameters, with the first potential parameters, forces between atoms were smaller, more compressible. For the elastic constants, the second potential parameters can not consider the effects of temperature and pressure; elastic constants changed with temperature and pressure were computed with the first potential parameters. The results were in good accordance with the experiments and the first principles calculations. There is a sudden change when the elastic constant changed with the pressure which can be guessed as the phase transition. The pressure was 320 Gpa which was in accordance with the the first principles calculations. In short, the first potential parameters can reflect the structural characteristics of beryllium more comprehensive than the first one.

关 键 词：分子动力学方法 修正型嵌入原子势 状态方程 弹性常数 

分 类 号：O52[理学—高压高温物理]