The behaviors of He atoms at Ti3SiC2(001)/V(110) interface: A first-principles study

Abstract

Ti3SiC2 nano-particles and He atom play an important role for the degradation of properties in vanadium alloys under irradiation environment. Herein, the behaviors of He atoms at C-Ti2-H Ti3SiC2(001)/V(110) interface model by first-principles calculations, which is the most thermodynamically stable, is studied to elucidate the effect of Ti3SiC2 nano-particles on the He bubble formation in the vanadium alloys. He atom tends to dissolve at the Ti3SiC2/V interface and at the near Si layer of Ti3SiC2 side at the interface. The vacancy type defects formation energies for V1, C1, C2 and Si, which both lower than V monovacancy formation energy in bulk vanadium, are more likely to form at the interface. Moreover, The existence of monovacancy at the interface makes it easier for neighboring He atoms to dissolve, which has a spatial effect on He atom. The result of the trapping energy and the interface distortion of He atom trapped by Si and V1 vacancies, more He atoms can be trapped as the number of vacancies increases. The diffusion of He atom located at Ti3SiC2 side towards the interface hampered by the small spacing Ti and C atom layers (dlsTi2−C2= 1.18 Å) anddlsTi1−C1 = 1.31 Å) He atom tends to aggerate at the interface due to the higher energy barrier. The Ti3SiC2-praticle/V-matrix interface can act as a sink for He atom. These findings provide a new insight into the understanding about the influence of Ti3SiC2 nano-particles on the mechanisms of He bubble formation and the guidance for further the preparation of vanadium alloys.