分子动力学研究钚晶体中的氦泡迁移与合并

Molecular-dynamics study transfer and combination of helium bubbles in plutonium crystal

本文建立了钚材料自辐照老化中的氦泡原子模型,用修正嵌入原子多体势和并行分子动力学计算方法,模拟了氦泡在钚晶格中的稳定结构、氦泡的迁移合并、以及氦泡生长引起的晶体缺陷等,并分析了氦泡长大机制及由氦泡引起的钚晶体体积变化。计算结果表明,氦原子聚集成泡现象与金属Ti中氦原子聚集成泡行为一致,氦泡长大遵循自捕陷和冲出位错环机制,氦泡周围的缺陷随着氦泡的生长加剧,仅由氦泡引起的体积肿胀很小,体积演化经历了一个先突然增大到体积膨胀的上限,然后随弛豫时间逐渐减小到最终体积的过程,中间有一个自我修复或缺陷恢复的阶段。研究结果提高了对氦泡长大机理及氦泡相互作用规律的理解。

The paper build the characterization and modeling of helium bubbles in self-irradiated plutonium （Pu） materials. Using parallel molecular dynamics method with the embedded atom method （EAM） potential, we imitated the stable structures and combination of helium bubbles in 5-plutonium crystal lattice, and the lattice damage generated by helium bubbles. We also analyzed the grown mechanism of helium bubbles and bulk swell of Pu crystal due to helium bubbles. The calculations reveal that the helium gathering and generate bubbles like their behavior in Ti metals, helium bubbles grow up following the self-capture and dislocation dash out mechanism, and defects in Pu metals prick up by helium bubbles grow up. We realize that the bulk swell of Pu crystal due to helium bubbles is very small, and there is a self-improvement or lattice comeback process in bulk transformation, because the bulk enlarged to upper limit fleet at the first, and then monished to final volume with time of relax gently. The research improved our understanding of helium cluster grow up and interactional regulation.