单晶Cu冲击加载及卸载下塑性行为的微观模拟

Molecular dynamics study on the plastic behavior of monocrystalline copper under shock loading and unloading

使用分子动力学方法对室温下单晶铜沿[001]和[111]方向冲击加载及卸载下的塑性行为进行了模拟,得到了Hugoniot关系以及冲击熔化压力,与实验基本符合.加载过程中,较高的初始温度有利于位错的形核与发展.通过对冲击波在自由表面卸载过程的模拟和分析发现:卸载过程呈现"准弹性卸载行为";沿[001]方向卸载后大量不全位错环与堆积层错消失,而沿[111]方向卸载后只有少量层错消失,部分层错甚至会发展扩大.

Molecular dynamics simulations were used to study the plastic behavior of copper monocrystal under shock loading and unloading. We obtained the Hugoniot relation for both [ 001 ] and [ 111 ] orientations and the melting pressure, which turns out to be in agreement with experiment. The results showed that higher initial temperature increases the possibility for the dislocation loop generate and expansion. The release behavior after the shock wave reaching the back of the sample was also analyzed. We found that the release behavior was quasi-elastic and most of the stacking-fault networks disappear behind the release wave along [001 ] orientation while few stacking faults disappear along [ 111 ] orientation.