First-principles study of the behaviors of He atoms at TiC(110)/V(110) interface

Abstract

The behaviors of He atoms at TiC(110)/V(110) interface with center-site stacking, which has the most covalent-ionic bond, using first-principles calculations are studied to clarify the effect of TiC-precipitate on the He bubble formation in the vanadium alloys. The results show that He atom prefers to dissolve at TiC/V interface compared with bulk vanadium, and the dissolved He atom would cause the interface to swell, but has little influence on the electronic properties of the interface. It can be explained by He atom with a typical closed shell structure, which is hardly chemically reactive with other elements. The TiC-precipitate promotes the vacancies formation at the interface. He atoms are easier to dissolve at the interface where exists vacancies. The maximum number of He atoms that can be trapped by the interface with V monovacancy is thirteen, moreover the interface can trap more He atoms with the increasing of vacancies. In addition, the smallest energy barrier of He atom from the interface to the interior bulk vanadium is 0.67 eV, which is almost six times higher than that in bulk vanadium (0.11 eV), suggesting that the He atom dissolved at the interface is difficult to escape to bulk vanadium. In conclusion, TiC/V interface is a possible nucleation position of He bubbles. The findings can provide the theoretical strategy for further designing, fabricating and processing of vanadium alloys used in nuclear structure materials.