关键词: 分子动力学模拟, 应力-应变曲线, 非晶化

Abstract: Molecular dynamics simulations were performed for studying mechanical properties of nickel nanowires subjected to uniaxial strain using embedded atommethod (EAM) potential. Strain rates applied in the simulations ranged from 5×10^7 s^-1 to 1×10^10 s^-1. The stress, the average atomic energy, the pair correlation function, as well as the transient atomic images of the systems were presented to explore the strain rate dependence of structure of nanowires. It was found that as the strain rates applied to the system were lower than 1×10^8 s^-1, the nanowires underwent plastic deformation and kept crystal structure before fracture during the process of tensioning state, which was testified clearly by the pair correlation function. While as strain rates were higher than 1×10^9 s^-1, the nanowires changed continuously from crystalline structure to amorphous phase and the pair correlation function also exhibited the characteristics of typical amorphous peaks. Amorphization of Ni nanowires was induced under high strain rates.

Key words: Molecular dynamics simulation, Stress-strain curves, Amorphization