First-Principles Study of the Stability of Ti n O m Clusters and He Behavior Inside Ti n O2Va1 Clusters in Vanadium Alloy

Abstract

In order to characterize the behaviors of interstitial oxygen (O) in the vanadium (V) alloy, the interactions between O and Ti with respect to atomic separation distance have been investigated using first-principles calculations. We observe an attractive interaction between Ti and O within the third nearest neighbor (nn) (3nn) distance. The stability of the Ti-vacancy (Ti-Va) clusters has been studied by calculating the binding energy between Ti and monovacancy in the vanadium alloy, and our results show that the stable configurations are Ti1Va1, Ti2Va1, and Ti4Va1 clusters. The TinVa1 clusters prefer to trap two O atoms and form stable Ti1O2Va1, Ti2O2Va1, and Ti4O2Va1 clusters. Furthermore, the self-trapping energies of the Hex clusters by the TinO2Va1 clusters have been calculated. When four He atoms are trapped, the Hex clusters are stable. Furthermore, the trapping energies for the multiple He atoms captured by the TinO2Va1 clusters are calculated, and the TinO2 clusters are found to impede the vacancy trapping of He atoms to form He bubbles.