The first principles study on the structures, mechanical properties and electronic structures of Ti-V alloys

The crystal structures, electronic structures and mechanical properties of Ti₃V, TiV and TiV₃ of TiV alloys were studied by using the first principle method based on density functional theory. The results show that TiV₃ has the most stable structure, followed by TiV, Ti₃V has the weakest stability, but Ti₃V has the strongest formation ability. Compared with the self-interstitial configuration of Ti, the self-interstitial configuration of V is easier to be formed. Whether it is Ti self-interstitial or V self-interstitial, the formation energy of self-interstitial of TiV₃ is the largest. The calculation of mechanical properties shows that all three alloys meet the mechanical stability standard and are ductile materials. The calculation of volume modulus and hardness shows that TiV₃ has the highest hardness, TiV follows, Ti₃V has the lowest hardness, which is consistent with the calculation results of self-interstitial energy. The electronic structure calculation shows that at the Fermi level, the state densities of the three alloys are mainly provided by the p and d orbitals of Ti and V, and the electronic structure of the TiV₃ alloy is the most stable. Differential charge density calculation shows that metallic properties are stronger than covalency in Ti₃V alloy. In Ti₃V, TiV and TiV₃ alloys, the metallicity decreases and the covalency increases gradually, and the alloy becomes stable. (authors)