含圆孔纳米薄膜在拉伸加载下变形机理的原子级模拟研究

The deformation mechanism of nanofilm with void under tensile loading:An atomistic simulation study

采用分子静力学方法结合量子修正的Sutton-Chen多体势研究了含圆孔的纳米薄膜在单向加载过程中的力学行为,并采用共近邻分析方法研究了薄膜的微结构演化过程.模拟结果表明:孔洞的引入显著地降低了纳米薄膜的杨氏模量和屈服应力;在拉伸过程中,孔洞的形状随着应变的增加逐渐由圆形变为椭圆形,最终孔洞闭合;纳米薄膜在进入塑性变形阶段后,薄膜内部出现原子的堆跺层错,这种层错结构的出现是肖克莱不全位错在薄膜内部沿着{111}面的[112]方向运动的结果.

In this paper,we employ molecular static approach with quantum corrected Sutten-Chen many-body potential to study the mechanical behavior of nickel nanofilm during uniaxial loading,and investigate its microstructure by common neighbor analysis methods.The simulated results show that the existence of void significantly weakens the Young＇s modulus and yield stress of nanofilm;with the increased strain,the shape of void changes from circular into elliptical,and the void is eventually entirely closed.The plastic deformation of nanofilm is characterized by {111} glide associated with Shockley partial dislocations,resulting in the formation of stacking faults.