The evolution of dislocation loop and its interaction with pre-existing dislocation in He+-irradiated molybdenum: in-situ TEM observation and molecular dynamics simulation
The evolution of dislocation loop and its interaction with pre-existing dislocation in He+-irradiated molybdenum: in-situ TEM observation and molecular dynamics simulation
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He 辐照钼中位错环的演化及其与预先存在的位错的相互作用：原位 TEM 观察和分子动力学模拟
DOI：
10.1016/j.actamat.2020.10.022
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发表时间：
2020-12
期刊：
影响因子：
9.4
通讯作者：
Yong Xin
中科院分区：
文献类型：
--
作者：
Yipeng Li;Guang Ran;Yijia Guo;Zhipeng Sun;Xinyi Liu;Yuanming Li;Xi Qiu;Yong Xin
采用TEM原位观察和分子动力学模拟方法研究了673 K下30 keV He+辐照钼中辐照诱导位错环的演化及其与原有位错线的相互作用。详细研究了位错环的形核、湮灭、合并、尺寸变化和类型，分析了位错环的硬化效应。随着氦注量的增加，位错环的体积数密度迅速增加，然后缓慢下降到一个饱和值，而位错环的平均尺寸不断增加，直到达到一个上限。在<111><100>3.95 × 1015 He +.cm−2（0.07 dpa）时，1/2和环都形成，比例为60.2%至39.8%。预先存在的位错线会抑制位错环的形核和生长，而辐照诱导的位错环对位错线有很强的钉扎作用，阻碍了位错线的运动。利用分子动力学模拟阐明了原位实验中观察到的线-环相互作用的一些主要特征的原子机制，结果显示出很好的一致性。不同的相互作用过程取决于位错环的Burgers矢量和位错面、位错段的运动和反应动力学以及外载荷。
In-situ TEM observation and molecular dynamics simulation were used to investigate the evolution of irradiation-induced dislocation loops and their interactions with the pre-existing dislocation lines in molybdenum irradiated by 30 keV He+at 673 K. The nucleation, annihilation, merging, size change, and types of dislocation loops were investigated in detail, and the hardening effect from dislocation loops was analyzed. With the increase of helium fluence, the volume number density of dislocation loops increased rapidly and then decreased slowly to a saturation value, while the average size of dislocation loops increased continuously until it reached an upper limit. Both 1/2<111> and <100> loops were formed, with a proportion of 60.2% to 39.8% at 3.95 × 1015He+.cm−2(0.07 dpa). The pre-existing dislocation lines would suppress the nucleation and growth of the dislocation loops, while the irradiation-induced dislocation loops had a strong pinning effect on the dislocation lines and impeded their motion. Molecular dynamics simulations were used to clarify the atomistic mechanisms of some major features of the line-loop interactions observed in the in-situ experiment, which showed in a good agreement. The different interaction processes depended on the Burgers vector and plane of the dislocation loop, the motion and reaction kinetics of dislocation segments, and the external loading.
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期刊：
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影响因子：
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作者：
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