Mechanical Property and Deformation Mechanism of Gold Nanowire with Non-Uniform Distribution of Twinned Boundaries: A Molecular Dynamics Simulation Study*

The mechanical property and deformation mechanism of twinned gold nanowire with non-uniform distribution of twinned boundaries (TBs) are studied by the molecular dynamics (MD) method. It is found that the twin boundary spacing (TBS) has a great effect on the strength and plasticity of the nanowires with uniform distribution of TBs. And the strength enhances with the decrease of TBS, while its plasticity declines. For the nanowires with non-uniform distribution of TBs, the differences in distribution among different TBSs have little effect on the Young’s modulus or strength, and the compromise in strength appears. But the differences have a remarkable effect on the plasticity of twinned gold nanowire. The twinned gold nanowire with higher local symmetry ratio has better plasticity. The initial dislocations always form in the largest TBS and the fracture always appears at or near the twin boundaries adjacent to the smallest TBS. Some simulation results are consistent with the experimental results.