Migration of vacancies, He interstitials and He-vacancy clusters at grain boundaries in α-Fe

被引：41
作者：
Gao, F. [1 ]
Heinisch, H. L. [1 ]
Kurtz, R. J. [1 ]
机构：
[1] Pacific NW Natl Lab, Richland, WA 99352 USA
来源：
JOURNAL OF NUCLEAR MATERIALS | 2009年 / 386-88卷
关键词：
COMPUTER-SIMULATION; DIMER METHOD; HELIUM; DEFECTS; DISLOCATIONS; DIFFUSION; IRON;
D O I：
10.1016/j.jnucmat.2008.12.159
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
The dinner method for searching transition states has been used to systematically study possible migration paths of vacancies, He interstitials and He-vacancy (He/V) clusters at Sigma 11 < 110 > {323} and Sigma 3 < 110 > {111} grain boundaries (GBs) in alpha-Fe. Vacancies trapped at the GBs diffuse along the GBs with migration energies much less than that within the perfect crystal. Long-time dynamics simulations of diffusion pathways reveal that vacancies migrate one-dimensionally along specific directions in both GBs: directly along close-packed rows in the Sigma 3 GB, and in zigzag paths within the Sigma 11 GB. Also, dimer saddle point searches show that He interstitials can diffuse along the GBs with migration energies of 0.4-0.5 eV, similar to those of individual vacancies at the GBs, and the corresponding mechanisms are determined. The rate-controlling activation energy for migration of a He-divacancy cluster in the GBs determined using the dimer method is about 0.9 eV. This is comparable to the migration energy for a He-divacancy cluster in bulk alpha-Fe. (C) 2009 Elsevier B.V. All rights reserved.
引用
收藏
页码：390 / 394
页数：5
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