Molecular dynamics simulations of effects of stacking fault energies on defect formation process in FCC metals

FCC金属における欠陥生成プロセスに対する積層欠陥エネルギーの影響

沖田 泰良*; 板倉 充洋  ; 中西 大貴*; 川畑 友弥*

Okita, Taira*; Itakura, Mitsuhiro; Nakanishi, Daiki*; Kawabata, Tomoya*

Molecular dynamics simulations were conducted to evaluate the influence of the stacking fault energy on defect formation by collision cascades in FCC metals. The simulations were performed for PKA energies of 1-50 keV by using six sets of EAM potentials that differed only in SFEs. Neither the number of residual defects nor their clustering behavior is affected by SFE, except for the mean size of vacancy clusters at highest PKA energy. The mean size increases as the SFE decreases because of enhanced formation of large vacancy clusters, which prefer to comprise stacking fault structure inside them. The ratio of glissile SIA clusters decreases as the SFE increases. At higher SFEs, both the number of Frank loops and perfect loops tend to decrease; instead, three-dimensional clusters form with higher densities. The effect of SFE on the number of Frank loops becomes apparent only at the highest PKA energy, where comparably large SIA clusters can be formed with a higher density.