Defect formation mechanisms in metal nanowire under cyclic loading: a molecular dynamics study

A series of molecular dynamics simulations were conducted to reveal the fatigue mechanisms in metal nanowires. We applied axial cyclic loading deformation on a copper single-crystal nanowire model and observed the deformation process during cycle evolution. The detailed observation revealed that the deformation mechanisms in the nanowire is essentially different from the case of the macro- and micro-scaled materials because of the lack of dislocation sources. We also found that atomic vacancies were formed continually by dislocation motion even under a simple single-slip condition. The accumulation of vacancies is expected to be a probable mechanism of fatigue in nanomaterials.

Automated summary

A series of molecular dynamics simulations were conducted to investigate the fatigue mechanisms in metal nanowires. By applying axial cyclic loading deformation on a copper single-crystal nanowire model, the deformation process during cycle evolution was observed. It was found that the deformation mechanisms in nanowires differ significantly from macro- and micro-scaled materials due to the absence of dislocation sources. Continuous formation of atomic vacancies by dislocation motion, even under a simple single-slip condition, was also identified. The accumulation of vacancies is expected to be a probable mechanism of fatigue in nanomaterials.