Effect of damage rate on the kinetics of void nucleation and growth by phase field modeling for materials under irradiations

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• 作者：Xuejian Ding ; Jiejiang Zhao ; Hao Huang ; Shurong Ding ; Yongzhong Huo ; ^{yzhuo@fudan.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Modified Cahn-Hilliard equation ; Explicit nucleation algorithm ; Vacancy generation and accumulation ; Void formation and growth kinetics ; Irradiation effects
• 刊名：Journal of Nuclear Materials
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：480
• 期：Complete
• 页码：120-128
• 全文大小：1128 K

文摘

The void formation and growth in materials under irradiations is studied by a modified Cahn-Hilliard equation coupled with the explicit nucleation algorithm. Through the numerical simulations, the stages of incubation, nucleation, growth and coalescence of the irradiation induced voids are clearly observed with a faster kinetics for stronger damage rate. There seems to exist a critical damage rate ${\dot{g}}_v^c$ at which the kinetics speeds up significantly. For smaller damage rates, very few voids can be nucleated. But the nucleated voids can grow rather large with its average radius growing as R_v∝$\propto$t^1/d. For stronger irradiations, much more voids could be nucleated, but they cannot grow very large before coarsening. The growth follows a much faster kinetics as R_v∝$\propto$t^2/d. The critical damage rate ${\dot{g}}_v^c$ should be determined by the competition of the rate of diffusion and the rate of vacancy production due to irradiations.