First principles studies on the elastic, thermodynamic properties and electronic structure of Ti15−xMoxSn compounds

The structural, elastic, thermodynamic and electronic properties of the Ti15−xMoxSn compounds were systematically investigated by means of first-principles calculations based on the density functional theory (DFT). The calculated results demonstrate the Ti15−xMoxSn compounds still remain the stable β phase structure. The calculation of cohesive energy shows that the structural stability of the Ti15−xMoxSn compounds increases apparently with the increase of Mo content. According to Hooke's law, the single crystal elastic constants were obtained and show that all the calculated compounds keep mechanical stability. Then the bulk modulus B, shear modulus G, Young's modulus E and Poisson's ratio ν of polycrystalline aggregates were calculated at zero pressure. The calculated results show that among these Ti15−xMoxSn compounds, Ti4Mo11Sn exhibits the largest stiffness while Ti12Mo3Sn shows the greatest ductility. The compounds Ti12Mo3Sn and Ti11Mo4Sn with the two lowest elastic Young's modulus of 61.01 GPa and 65.59 GPa are expected to be promising metallic biomaterials for implant applications. Besides, the Debye temperature ΘD and the electronic density of states (DOS) are also investigated and discussed.