Influence of Vacancy on Structural Stability, Mechanical Properties and Electronic Structures of a Ti5Sn3 Compound from First-Principles Calculations

Abstract

Titanium alloy is widely used in biomedical materials. Ti-Sn alloy is a new type β titanium alloy with no toxicity. In this paper, the mechanical and electronic properties of Ti5Sn3 with vacancy defects have been studied by using first-principles method. The vacancy formation energy, vacancy formation enthalpy, elastic constant, elastic modulus, hardness and electronic structure of perfect Ti5Sn3 and Ti5Sn3 with different vacancies were also calculated and discussed. The results show that Ti5Sn3 is more likely to form vacancies at VTi2. In addition, the bulk deformation resistance of Ti5Sn3 is weakened by the vacancy, and the shear resistance, stiffness and hardness of Ti5Sn3 are increased by the Ti vacancy, but the brittleness of Ti5Sn3 is increased. On the contrary, the presence of Sn vacancy decreases the shear resistance, stiffness and hardness of Ti5Sn3, and increases the toughness of Ti5Sn3. By analyzing the change of electronic structure, it is found that removing the Ti atom at the VTi2 position can improve the interaction between atoms, while Sn vacancy can weaken the interaction.