金属纳米棒弯曲力学行为的分子动力学模拟

Molecular dynamics simulation on bending behaviour of metal nanorod

纳米结构的力学性能是纳米超微型器件设计的基础 ,分子动力学是研究纳米结构力学行为的有效方法 .本文采用镶嵌原子方法模拟金属铜纳米棒的弯曲力学行为 .计算结果表明由于尺寸效应和表面效应的影响 ,在纳观尺度下纳米结构表现出与宏观尺度下完全不同的力学特征 .金属纳米棒弯曲力学过程分为初始变形迟滞阶段、线弹性变形阶段和塑性变形阶段 .塑性变形阶段表现出“刚化”、“台阶”和较强的延性等特征 .

The mechanical behaviour of nanostructure is the basis of nanodevice design, and molecular dynamics method is a valid method for investigating this behaviour. Bending behaviour of Cu nanorod is simulated by the embedded atom method. The simulation results show that the mechanical behaviour in nanoscale is very different from that in macroscale. This difference results from the size effect and surface effect. The bending procedure of a metal nanorod consists of three steps: initial deformation delay I line elastic deformation I plastic deformation. In the plastic stage, there appear some characteristic behaviours such as rigidity reinforcement, step up, and considerable ductility to be seen.