Towards understanding the mechanism of titanium suppressing vacancy clustering/void nucleation in vanadium alloy

•We investigated the interaction between titanium (Tim) and vacancyn (Vacn) with m, n = 1–5 to illustrate the stabilizing effect of Ti on Vacn clusters.•The migration process of vacancy/its clusters in presence of Ti was determined by the CI-NEB calculations.•Ti additions provide more nucleation sites of vacancies, forming more small-size complexes.•Ti has a pinning effect on vacancy clusters and suppresses vacancy clustering/void nucleation.