Atomistic simulation on size-dependent yield strength and defects evolution of metal nanowires
Atomistic simulation on size-dependent yield strength and defects evolution of metal nanowires
复制标题
DOI：
10.1016/j.commatsci.2009.02.015
复制
发表时间：
2009-07
影响因子：
3.3
通讯作者：
Zhenyu Yang;Zi-Xing Lu;Ya-pu Zhao
中科院分区：
文献类型：
--
作者：
Zhenyu Yang;Zi-Xing Lu;Ya-pu Zhao
给出了一个基于连续介质力学的简单推导，表明在超小尺度下，表面应力是屈服强度的关键。采用改进的嵌入原子方法（MEAM）对单晶金属纳米线在拉伸载荷下的力学行为进行了分子动力学（MD）模拟。计算得到的屈服强度随纳米线截面积的减小而增大的规律与理论预测一致。在纳米线边缘观察到由层错引起的重取向。此外，基于缺陷演化的快照，详细讨论了屈服机制。不同晶向的纳米线在拉伸变形中表现不同。本文对金属纳米线塑性性能的研究将有助于进一步了解纳米材料的力学性能。
A simple derivation based on continuum mechanics is given, which shows the surface stress is critical for yield strength at ultra-small scales. Molecular dynamics (MD) simulations with modified embedded atom method (MEAM) are employed to investigate the mechanical behaviors of single-crystalline metal nanowires under tensile loading. The calculated yield strengths increasing with the decrease of the cross-sectional area of the nanowires are in accordance with the theoretical prediction. Reorientation induced by stacking faults is observed at the nanowire edge. In addition, the mechanism of yielding is discussed in details based on the snapshots of defects evolution. The nanowires in different crystallographic orientations behave differently in stretching deformation. This study on the plastic properties of metal nanowires will be helpful to further understanding of the mechanical properties of nanomaterials.