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早川 頌*; 沖田 泰良*; 板倉 充洋; 川畑 友弥*; 鈴木 克幸*
Journal of Materials Science, 54(16), p.11096 - 11110, 2019/08
被引用回数：11 パーセンタイル：42.21(Materials Science, Multidisciplinary)We performed molecular dynamics simulations of displacement cascades in FCC metals under Poisson's deformation using interatomic potentials differing in stacking fault energy (SFE), in order to investigate the effect of tensile strain on the SFE dependence of defect formation processes. There was no clear SFE dependence of the number of residual defects and the size distribution of defect clusters under both no strain and the applied strain, while the strain enhanced the defect formation to a certain extent. We also observed that the strain affected the formations of self-interstitial atom (SIA) clusters depending on their size and the Burgers vector. These results were consistent with the analysis based on the defect formation energies. Meanwhile, the number of SIA perfect loops was higher at lower SFE under both no strain and the applied strain, leading to an increase in the ratio of glissile SIA clusters with a decrease in SFE. Further, the absolute number of SIA perfect loops was increased by the applied strain, while the SFE dependence of the number of SIA perfect loops was not affected. These findings were associated with the difference in formation energy between an SIA perfect loop and an SIA Frank loop. The insights extracted from this study significantly contribute to the modeling of microstructural evolution in nuclear materials under irradiation, especially for low SFE metals such as austenitic stainless steels.
中西 大貴*; 川畑 友弥*; 土井原 康平*; 沖田 泰良*; 板倉 充洋; 鈴木 克幸*
Philosophical Magazine, 98(33), p.3034 - 3047, 2018/09
被引用回数：10 パーセンタイル：47.84(Materials Science, Multidisciplinary)原子炉内部で使用されるオーステナイト鋼は積層欠陥エネルギーが低いことで知られ、そのため積層欠陥を伴う照射欠陥クラスタが大きくなることが予想される。この傾向を定量評価するため、FCC金属のモデルポテンシャルにおいて積層欠陥エネルギーだけを変化させたものを用い照射欠陥生成の分子動力学シミュレーションを様々な温度において実行し、生成した照射欠陥クラスタの種類と数を調べた。その結果移動可能な格子間原子クラスタの生成数が積層欠陥エネルギーとともに大きく変化することが見出された。
沖田 泰良*; 板倉 充洋; 中西 大貴*; 川畑 友弥*
no journal, ,
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.
