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论文类型： 期刊论文

发表时间： 2014-01-01

发表刊物： JOURNAL OF NUCLEAR MATERIALS

收录刊物： SCIE、EI

卷号： 444

期号： 1-3

页面范围： 147-152

ISSN号： 0022-3115

摘要： Using first-principles calculations, we investigated the He and H effects on vacancy formation in bcc Fe. From energetic point of view, the presence of interstitial He (H) atom reduces vacancy formation energy and single He prefers to occupy vacancy center. One monovacancy can accommodate at least 20 He (or 5 H) atoms, with He-He (H-H) distances of 1.5-1.7 angstrom (1.8-2.38 angstrom) in the He-m-vacancy (H-m-vacancy) complexes. The shorter He-He distance and larger expansion of vacancy space after multiple He insertion may account for more number of He atoms trapped in vacancy with regard to H. Moreover, second vacancy formation energy around the He-vacancy complex decreases remarkably with increasing amount of He atoms. Thus, trapping of multiple He in a Fe monovacancy can induce formation of new vacancy at nearby lattice site, and several vacancy-SIA pairs would form concurrently. (C) 2013 Elsevier B.V. All rights reserved.