We have performed first-principles density functional theory calculations to investigate the retention and migration of hydrogen in Be_（22） W, a stable low-W intermetallic compound. The solution energy of interstiti...We have performed first-principles density functional theory calculations to investigate the retention and migration of hydrogen in Be_（22） W, a stable low-W intermetallic compound. The solution energy of interstitial H in Be_（22） W 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 Be_（22） W 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 Be_（22） W, 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 Be_（22） W 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.展开更多
基金Project supported by the National Magnetic Confinement Fusion Program of China(Grant Nos.2014GB104003 and 2015GB105001)the National Natural Science Foundation of China(Grant No.51504033)
文摘We have performed first-principles density functional theory calculations to investigate the retention and migration of hydrogen in Be_（22） W, a stable low-W intermetallic compound. The solution energy of interstitial H in Be_（22） W 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 Be_（22） W 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 Be_（22） W, 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 Be_（22） W 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.
