A theoretical approach to the structural, elastic and electronic properties of Ti8− xV4− yMox+y+zAl4− z lightweight shape memory alloys for biomaterial implant applications

Abstract

The physical properties of the off-stoichiometric Ti8−xV4−yMox+y+zAl4−z alloys to reduce toxic effects and increase biomaterial efficiency have been studied systematically with Density Functional Theory (DFT) based ab-initio calculation methods. The calculated formation and cohesive energies show that thermodynamic and structural stability of the Ti8−xV4−yMox+y+zAl4−z alloys increases due to the increase in Mo concentration. The results of Pugh's ratio (G/B) show that the ductility of all phases decreases with increasing Mo concentration (0.15 → 0.35). The plasticity of the Ti8−xV4−yMox+y+zAl4−z alloys is downgraded with the increase of Mo concentration by the Poisson's ratio υ. The Young's modulus E of Ti8V4Mo3Al1 and Ti8V3Mo4Al1 phases were calculated as 49.84 GPa and 48.71 GPa, respectively. These phases are very suitable candidates for real biomaterial applications. Further, the electronic structure shows that as Mo concentration increases the Ti-3d-Mo-4d bonds become stronger and phases become more stable by the effect of Ti–Mo bonds. © 2020 Elsevier B.V.