冲击加载下孔洞诱导相变形核分析  

Study of nucleation of void-induced phase transformation under shock compression

作　　者：邵建立[1] 王裴[1] 秦承森[1] 周洪强[1] 

机构地区：[1]北京应用物理与计算数学研究所,北京100088

出　　处：《物理学报》2008年第2期1254-1258,共5页Acta Physica Sinica

基　　金：国家自然科学基金与中国工程物理研究院联合基金重点项目(批准号:10476027);中国工程物理研究院科学技术发展基金(批准号:2007A09001)资助的课题.~~

摘　　要：用分子动力学方法模拟了冲击加载(沿[001]向)下单晶Fe中孔洞诱导相变形核及生长过程,并分析了初始温度对这一生长过程的影响.数值模拟显示:1)相变形核首先出现在孔洞周围的(110)和(110)面上,并分别沿[110],[110]向和[110],[110]向生长成片状,之后核的生长方向则变为沿〈111〉向,形成"V"形板条状新相颗粒;2)在相同冲击压力下,初始温度为300K时在新相晶核边缘出现许多核胚,生成的新相颗粒比60K时明显减小.这些现象表明,孔洞诱导相变形核及生长过程沿着特定晶向进行,而初始温度的升高可以分散孔洞对相变形核的诱导作用.统计了孔洞周围应力体积张量及能量的分布,对相变形核及生长过程进行了初步分析.Molecular dynamics simulations have been used to study the nucleation and growth of void-induced phase transformation of single crystal Fe under shock-wave loading along the [001] direction and effects of initial temperature on the process. It was found that： 1 ） phase transformation nucleates firstly on the （110） and （110） planes around the void and grows along the [110], [110] and [ 110], [110] directions, respectively, and then grow along （111） directions of the （110） and （110） planes, and ultimately ＂V＂ shaped grains form; 2） under the same shock compression, grains at initial temperature 300 K are smaller than those at 60 K, and at the same time, many embryos appear around the grains. These phenomena indicate that void-induced phase transformation nucleates and grows along certain directions, and increasing the initial temperature can diversify the action. Finally, we calculate the statictics of pressure-volume tensor and energy distributions, and give a preliminary analysis of the nucleation and growth of phase transformation.

关 键 词：相变 孔洞 分子动力学 

分 类 号：O482[理学—固体物理]