Effects of the Be22W phase formation on hydrogen retention and blistering in mixed Be/W systems Project supported by the National Magnetic Confinement Fusion Program of China (Grant Nos. 2014GB104003 and 2015GB105001) and the National Natural Science Foundation of China (Grant No. 51504033)

• Published in: Chinese physics B 2017-06, Vol.26 (7)
• Main Authors: Cao, Jin-Li, He, Bing-Ling, Xiao, Wei, Wang, Li-Gen
• Format: Article
• Language: English
• Subjects: first-principles; hydrogen
• ISSN: 1674-1056
• DOI: 10.1088/1674-1056/26/7/076801

We have performed first-principles density functional theory calculations to investigate the retention and migration of hydrogen in Be22W, a stable low-W intermetallic compound. The solution energy of interstitial H in Be22W is found to be 0.49 eV lower, while the diffusion barrier, on the other hand, is higher by 0.13 eV compared to those in pure hcp-Be. The higher solubility and lower diffusivity for H atoms make Be22W a potential beneficial secondary phase in hcp-Be to impede the accumulation of H atoms, and hence better resist H blistering. We also find that in Be22W, the attraction between an interstitial H and a beryllium vacancy ranges from 0.34 eV to 1.08 eV, which indicates a weaker trapping for hydrogen than in pure Be. Our calculated results suggest that small size Be22W particles in hcp-Be might serve as the hydrogen trapping centers, hinder hydrogen bubble growth, and improve the resistance to irradiation void swelling, just as dispersed oxide particles in steel do.