Design and mechanical properties of new β type titanium alloys for implant materials

Pure titanium and Ti-6Al-4V alloy have been mainly used as implant materials. V-free titanium alloys like Ti-6Al-7Nb and Ti-5Al-2.5Fe have been then developed because toxicity of V has been pointed out. Al- and V-free titanium alloys as implant materials have been developed. Most of them are, however, α + β type alloys. β type titanium alloys with lower moduli of elasticity and greater strength have been developed recently. Design of new β type titanium alloys composed of non-toxic elements like Nb, Ta, Zr, Mo or Sn with lower moduli of elasticity and greater strength were, therefore, studied based on the d-electron alloy design method, and the basic mechanical properties of designed alloys of button ingots melted by tri-arc furnace in the laboratory were investigated in this study. β type alloys, Ti-Nb-Ta-Zr, Ti-Nb-Ta-Mo and Ti-Nb-Ta-Sn system alloys designed in this study are expected to have greater performance for implant materials. The Young's moduli of these alloys are lower compared with that of Ti-6Al-4V ELI which has been used as an implant material. The alloys on which some heat treatments have been conducted offer suitable tensile properties as implant materials. The tensile strength and elongation of designed alloys in this study are equivalent or greater than required values already reported.