First-principles calculations of vacancy-O-He and vacancy-N-He complexes in vanadium AITranslate

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DOI：https://doi.org/10.1016/j.commatsci.2019.01.005

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Highlights • We investigate the interaction of He with vacancy and O/N atoms in vanadium. • The O/N impurities decrease the binding strength of He to vacancy clusters. • The stable configurations of vacancy-Om-Hen and vacancy-Nm-Hen are same. • Existence of O/N in vacancy weakens vacancy trapping for more He atoms. The synergistic interaction of solute O/N atom-vacancy-He in vanadium plays an important role in the evolution of radiation-induced microstructures and He bubbles. We investigate the interactions of He with solute O/N atom, the trapping of He in vacancy-Om/vacancy-Nm complexes and the stability of small vacancy-Om-Hen/vacancy-Nm-Hen clusters (m = 1–2, n = 1–5) in bcc vanadium using first-principles calculations. The interactions between He and O/N impurity are weak repulsion and He at all interstitial sites less than 2.2 Å from O (N) atom are unstable. The total binding energies of Hen to vacancy-Om and vacancy-Nm almost linearly increase with the number of He atoms, whose values are from 1.22 eV to 5.01 eV with n from 1 to 5. The vacancy-O(N)-Hen clusters are more stable than vacancy-O2(N2)-Hen clusters. The binding strength of He to vacancy-Om/vacancy-Nm overall has a significant drop compared with those of alone vacancy, and thus He dissolution from both complexes is easier. The existence of the O/N impurities weakens vacancy trapping ability for more He atoms and can reduce the growth and swelling of the trapping He clusters. Graphical abstract Download : Download high-res image (115KB) Download : Download full-size image