Non-equilibrium molecular dynamics simulations of the spallation in Ni: Effect of vacancies

T Qiu and YN Xiong and SF Xiao and XF Li and WY Hu and HQ Deng, COMPUTATIONAL MATERIALS SCIENCE, 137, 273-281 (2017).

DOI: 10.1016/j.commatsci.2017.05.039

The effects of defects on the fracture resistance of materials have attracted considerable attention recently. In the present work, the vacancy effects on the spallation in single-crystalline Ni are studied by nonequilibrium molecular dynamics simulations. The vacancy concentration ranges from 0% to 2.0%, and the spallation in shock wave loading along three low-index directions (001, 110, and 111) is investigated. We found that vacancies provide the sites of nucleation for compression-induce plasticity, and tension stress-induced plasticity plays the key role in void nucleation. Along the 001 direction, the degree of spall damage does not increase with the increase in vacancy concentration; however, along the 110 and 111 directions, it decreases with the increase in vacancy concentration when the vacancy concentration is higher than the threshold value. (C) 2017 Elsevier B.V. All rights reserved.

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