Coupling effects of stress and ion irradiation on the mechanical behaviors of copper nanowires

By using molecular dynamics simulations, we studied the ion irradiation induced damage in mechanically strained Cu nanowires and evaluated the effects of damage on the mechanical properties of nanowires. The stresses in the pre-strained nanowires can be released significantly by the dislocation emission from the cascade core when the strain is greater than 1%. In addition, comparison of the stress-strain relationships between the defect-free nanowire and the irradiated ones indicates that ion irradiation reduces the yield strength of the Cu nanowires, and both the yield stress and strain decrease with the increase of irradiation energy. The results are consistent with the microscopic mechanism of damage production by ion irradiation and provide quantitative information required for accessing the stability of nanomaterials subjected to mechanical loading and irradiation coupling effects.