【摘要】 使用分子动力学方法模拟了冲击波在纳米金属铜中的传播,模拟样品由Voronoi方法得到.结果显示纳米金属铜在冲击加载下呈现多次屈服的现象,并发现冲击波具有多波结构.由于设计样品时选择了晶粒取向,晶界滑移和位错在冲击波波形上被区分开.冲击波波阵面由弹性变形区、晶界滑移主导的塑性变形区和位错主导的塑性变形区组成.样品中弹性波前沿扰动较小,而位错主导的塑性波前沿扰动较大,造成后者的主要原因是波阵面上沿冲击方向不同取向晶粒的不同屈服行为.更多还原

【Abstract】 The propagation of shockwave in nanocrystalline copper has been studied by means of molecular dynamics simulation. The samples are prepared by Voronoi method and crystalline orientations of each grain are limited by three conditions. The result shows for the first time that nanocrystalline copper shows the phenomenon of multi-yield under shock loading,and the shockwave has a multi-wave structure. The profiles of shock-front suggest grain boundary sliding and dislocation emmision in sequence. The shock-front consists of an elastically deforming area,a plastically deforming area dominated by grain boundary sliding and a plastically deforming area dominated by dislocation movement. There are irregularities on both elastic wave and plastic wave,and the former is obvious than the latter.更多还原