论文部分内容阅读
利用分子动力学方法模拟计算了单晶铜中纳米孔洞在沿〈111〉晶向冲击加载下增长的早期过程.测量发现不同加载强度下等效孔洞半径随时间近似成线性变化.观测到单孔洞增长的两种位错生长机理加载强度较低时,只在沿着冲击加载方向的孔洞顶点附近区域有位错的成核和运动;而随着加载强度超过一定阈值,在沿冲击加载和其垂直方向的孔洞顶点区域都观察到位错的成核和运动.在前一种机理作用下,孔洞只沿加载方向增长;在后一种机理作用下,孔洞同时沿加载和垂直于加载方向增长.分析孔洞表面原子的位移历史,发现沿加载及与其垂直方向的孔洞顶点沿径向的速度基本恒定,由此提出了一个孔洞生长模型,可以解释孔洞增长的线性生长规律.
The early process of the growth of nanopores in monocrystalline copper under impact load along the <111> crystal was simulated by molecular dynamics method. It was found that the equivalent cavity radius changed linearly with time at different loading strengths. The growth mechanism of the two dislocations is low when the loading strength is low, and only nucleation and motion of dislocation exist in the region near the apex of the hole along the direction of impact loading; and as the loading strength exceeds a certain threshold, The nucleation and movement of dislocations are observed in the vertical apex of the hole, and the holes grow only along the loading direction under the former mechanism. In the latter mechanism, the holes grow along both the loading and perpendicular to the loading direction. Based on the analysis of the displacement history of the atom on the surface of the hole, we found that the velocity of the hole in the direction perpendicular to the loading and its vertical direction is basically constant. Therefore, a hole growth model is proposed to explain the linear growth law of the hole growth.