The influences of migration behaviors on annihilation of point defects trapped into grain boundaries in Tungsten

WH He and LF Zhou and X Gao and D Wang and TL Shen and ZG Wang and DY Yang and YH Li and JT Liu and ZY Liu, JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 58, 218-225 (2021).

DOI: 10.1080/00223131.2020.1817809

The nano-crystalline materials generally show better irradiation resistance than common poly-crystalline materials since grain boundaries (GBs) can usually enhance the annihilation of irradiation-induced defects. Although the defect annihilation mechanism has been thoroughly investigated in GBs in tungsten, the influences of defect migration behavior in GB-planes on the recombination capability between them are still not well understood. In view of this, several GBs with typical divergences of point defect migration behavior are selected to conduct this study. And then the evolutions of Frenkel pairs continuously introduced into these GB-planes are simulated with the molecular dynamic methods at 1200 K. Combined the point defect migration behaviors in GB- planes, it is found out that the GB satisfying the following two conditions may have more excellent recombination ability of point defects trapped into it. Firstly, the vacancy (V) and self-interstitial atom (SIA) migration abilities are similar in the GB-plane. Secondly, the V or SIA migration abilities along two orthogonal directions in the GB-plane are similar.

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