孔洞和孪晶界对银纳米线形变行为联合影响的分子动力学模拟（英文）

Combined Effects of the Hole and Twin Boundary on the Deformation of Ag Nanowires: a Molecular Dynamics Simulation Study

在分子动力学模拟的基础上,系统地研究了银纳米线在单轴拉伸条件下的塑性形变。本文研究了不同孔径大小的[111]晶向的孪晶纳米线的力学性能。研究发现,孔洞的存在对弹性形变阶段没有影响。孪晶界上的孔洞在塑性形变阶段主要有两个作用。在初始塑性形变阶段,当孔洞的尺寸较小时,主要是作为位错源产生新的位错;随着孔洞尺寸的增大,主要作用变为阻碍位错滑移。在塑性形变的后期,孔洞的两个作用相辅相成,但随着孔洞尺寸的增大,孔洞作为位错源产生位错的作用变得显著,最终导致纳米线的塑性减弱。

Based on molecular dynamics simulations, the plastic deformation of silver nanowires under uniaxial tension has been studied systematically. In this paper, the mechanical properties of [111]-oriented twin nanowires with different hole sizes have been studied. The existence of holes has no effect on the elastic deformation stage. The hole on the twin boundary has two main roles in the plastic deformation stage. During the initial stages of plastic deformation, the main function of the hole is to produce new dislocations as dislocation sources at small hole sizes. Upon increasing the hole size the main effect changes to stop dislocation slip. During the late stages of plastic deformation, the two functions of the hole complement each other, upon increasing the hole size, the function of the hole as dislocation sources becomes obvious, leading to weakening of the plasticity of the nanowires.