First principles study of phase stability and elastic properties of Ti94Mo6-xZrx (where x: 2 ≤ x ≥ 5) for biomaterials

Abstract

Elastic modulus is a very important physical aspect for biomaterials which is impartial to various replacements as artificially hip joints, bone plate, and gum implants since it measures the material’s resistance to be deformed elastically. This is because “stress shielding effect” will result in the re absorption of natural bone and the implant loosening if a great difference of elastic modulus exists between the biomaterial implant and human bone. In this study first principle calculations have been performed to study the β-phase of Ti-Mo-Zr system to improve its elastic moduli. The phase stability of Ti₉₄Mo_6-xZr_x (where x: 2 - 5) alloys was investigated with respect to their equilibrium lattice parameters, elastic constants and the density of states. The results suggest that the Youngs moduli can be significantly enhanced with the addition of Zirconium (Zr) and decreasing Molybdenum (Mo) concentration while keeping Titanium (Ti) constant, which indicates phase stability. The Youngs modulus of structures Ti₉₄Mo_6-xZr_x was found to be between -2GPa and 24GPa. The electronic density of states curves also showed phase stability for structures Ti₉₄Mo₄Zr₂ since it was observed that the Fermi level is located close to the valley of the pseudogap. The results obtained are in agreement with the available experimental data and showed a similar trend. The study has shown that Zr has improved the elastic properties and the phase stability of Titanium alloy.