Inert gas bubbles in bcc Fe

JOURNAL OF NUCLEAR MATERIALS

卷:470

Article

Gai, Xiao¹  Smith, Roger¹  Kenny, S. D.¹ 

[1] Univ Loughborough, Dept Math Sci, Loughborough LE11 3TU, Leics, England

关键词: He;    Ar;    Xe bubbles;    Radiation damage;    Molecular dynamics;    Energy barriers;    Diffusion;   

DOI  :  10.1016/j.jnucmat.2015.11.057

来源: Elsevier

【 摘 要 】

The properties of inert gas bubbles in bcc Fe is examined using a combination of static energy minimisation, molecular dynamics and barrier searching methods with empirical potentials. Static energy minimisation techniques indicate that for small Ar and Xe bubbles, the preferred gas to vacancy ratio at 0 K is about 1:1 for Ar and varies between 0.5:1 and 0.9:1 for Xe. In contrast to interstitial He atoms and small He interstitial clusters, which are highly mobile in the lattice, Ar and Xe atoms prefer to occupy substitutional sites and any interstitials present in the lattice soon displace Fe atoms and become substitutional. If a pre-existing bubble is present then there is a capture radius around a bubble which extends up to the 6th neighbour position. Collision cascades can also enlarge an existing bubble by the capture of vacancies. Ar and Xe can diffuse through the lattice through vacancy driven mechanisms but with relatively high energy barriers of 1.8 and 2.0 eV respectively. This indicates that Ar and Xe bubbles are much harder to form than bubbles of He and that such gases produced in a nuclear reaction would more likely be dispersed at substitutional sites without the help of increased temperature or radiation-driven mechanisms. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.

【 授权许可】

Free