冲击加载下孔洞贯通的微观机理研究  

Microscopic mechanism of void coalescence under shock loading

作　　者：邓小良[1] 祝文军[1,2] 宋振飞[1] 贺红亮[1] 经福谦[1,2] 

机构地区：[1]中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室,绵阳621900 [2]四川大学物理科学与技术学院,成都610064

出　　处：《物理学报》2009年第7期4772-4778,共7页Acta Physica Sinica

基　　金：冲击波物理与爆轰物理国防科技重点实验室基金(批准号:9140C6703010804,9140C6701010902);中国工程物理研究院科学技术发展基金重点项目(批准号:2007A01004);国家自然科学基金NSAF联合基金项目(批准号:10876014)资助的课题~~

摘　　要：利用分子动力学方法计算模拟了沿〈100〉晶向冲击加载下单晶铜中双孔洞的贯通过程.发现孔洞周围发射剪切型位错环是孔洞塌缩和增长的原因.在拉伸阶段,孔洞首先分别独立增长,随后其周围塑性变形区开始交叠和相互作用,最后两个孔洞开始直接贯通.这种贯通模式和实验对延性材料中孔洞贯通过程的显微观察结果一致.对四种不同θ值(θ为两个孔洞中心连线与冲击加载方向之间的夹角)的模型分别进行了计算模拟,发现在相同的冲击加载强度下,θ=0°和θ=30°的孔洞之间没有相互贯通;而在θ=60°和θ=90°的孔洞之间观察到了贯通现象,而且θ=60°比θ=90°的构型更容易贯通.根据单孔洞周围位错发射特征,对上述现象在微观机理上进行了深入分析和解释.The influence of void configuration on void coalescence in single crystal copper under shock loading along [ 100] direction has been investigated with molecular dynamics （MD） simulation. The results reveal that the voids collapse and grow by means of emission of shear dislocation loops. In the tension stage, the voids first grow independently, then the plastic zone around the voids begin to interact and overlap, leading to the void coalescence. The pattern of void coalescence observed in our simulations coincides with the microscopic experimental results. We calculated for four different configurations, characterized by the angle （θ） formed by shock direction and the line connecting the two centers of voids, and found that among the four configurations, the coalescence of the voids prefers to occur where θ is 60°. Based on the resolved shear stress model around the void, we can clearly explain the simulation results.

关 键 词：纳米孔洞 分子动力学 冲击加载 贯通 

分 类 号：O347.1[理学—固体力学]