Abstract
Helium (He) has a synergistic effect on hydrogen (H) retention in metallic plasma-facing materials for nuclear fusion devices, which further makes a potential impact on hydrogen bubble formation in the materials. Using first-principles calculations, we investigated the interactions between H and He in molybdenum. The calculated results show that the binding energies of H are decreased at the pre-formed He-vacancy complex compared to those at the monovacancy without He. This indicates H trapping at the He-vacancy complex is energetically less favorable and the plasma-facing material will have less H retention. Most importantly, we revealed the critical characteristics of hydrogen concentration with the presence of He based on a thermodynamic model and the calculated energies of HmHeV complexes. The existence of He could apparently enhance the critical hydrogen concentration beyond which an initial stage of hydrogen bubble formation will occur. Our findings provide explicit evidences for the suppressing effect of helium on hydrogen bubble formation in molybdenum.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.