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Indexed by:期刊论文

Date of Publication:2014-07-01

Journal:COMPUTATIONAL MATERIALS SCIENCE

Included Journals:SCIE、EI

Volume:90

Page Number:116-122

ISSN No.:0927-0256

Key Words:Beryllium; Extrinsic interstitial atoms; Vacancy; First-principles

Abstract: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.