The effects of hydrogen, vanadium, and vacancies on the structural and energetic characteristics of the face-centered cubic titanium phase are studied using ab initio modelling. It is shown that the introduction of vanadium moderately affects the lattice constants and the bulk modulus, decreasing the cell volume and enhancing the rigidity of the structure. Hydrogen is found to preferentially occupy octahedral sites with a solution enthalpy of –0.67 eV, which is 0.13 eV more favorable than the location in tetrahedral sites. The influence of vacancies appears as a local weakening of interatomic bonds and a decrease in the bulk modulus. A comprehensive analysis of hydrogen–vacancy, hydrogen–vanadium, and vacancy–vanadium interactions shows that the nature of these interactions strongly depends on the local environment of defects. The results for ternary complexes (hydrogen–vacancy–vanadium) are especially interesting: it is shown that the presence of vanadium in the second sphere strengthens the bond between hydrogen and the vacancy. The data obtained provide a deeper understanding of titanium’s behavior during thermal hydrogen treatment and vanadium alloying, which is essential for creating strong and heat-resistant alloys of a new generation.
Kardash et al. (2025) studied this question.