单晶铜纳米线弯曲、扭转的变形机制的分子动力学研究

Abstract

Molecular dynamics simulations are used to investigate the mechanical behaviors of <001>/{100} and <110>/{111} single-crystalline Cu nanowires under bending and torsion. In the numerical simulations of <001>/{100} Cu nanowires subjected to bending, some fivefold deformation twins are observed at large bending angles. It is found that a reciprocal phase transformation from atoms of other 12-coordinate lattice to hcp lattice plays an important role in forming the fivefold deformation twins. Therefore, the formation process is distinct from that reported by Cao and Wei [Appl. Phys. Lett. 89, 041919 (2006)] in nanocrystalline Cu systems. However, for the <110>/{111} counterparts under bending, fivefold deformation twin can not be observed during the whole deformation process. In addition, we reveal that the emission of full dislocations from the two ends of the wire is the major deformation mechanism for <001>/{100} Cu nanowires to torsion, while for <110>/{111} Cu samples, the nucleation of full dislocations from the side surfaces is responsible for the torsion plastic deformation.