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论文类型： 期刊论文

发表时间： 2014-07-01

发表刊物： COMPUTATIONAL MATERIALS SCIENCE

收录刊物： SCIE、EI

卷号： 90

页面范围： 116-122

ISSN号： 0927-0256

关键字： Beryllium; Extrinsic interstitial atoms; Vacancy; First-principles

摘要： We present a first-principles study of the interactions between extrinsic atoms (H, He, O, C) with vacancy defects in hexagonal close packed (HCP) beryllium (Be). Presence of a vacancy reduces solution enthalpies of O and C by about 0.60 eV and 0.80 eV, respectively, but does not change their preferential sites. In perfect Be, both O-O and C-C pairs are attractive, while H-H and He-He pairs exhibit weak repulsion. Out-of-plane configurations for the O-O and C-C pairs are always more stable than the other configurations in Be HCP lattices. Moreover, we found strong attraction between the O/C atoms and the H/He atoms, weak attraction of H-He pairs, and strong repulsion of O-C pairs. Thus, we suggest that the interstitial O and C impurities provide trapping sites for H and He impurities and hinder their diffusion inside Be metal. (C) 2014 Elsevier B. V. All rights reserved.