Influence of Zr content on phase transformation, microstructure and mechanical properties of Ti 75− xNb 25Zr x ( x = 0–6) alloys

Abstract

Ternary Ti–Nb–Zr alloys consisting of biocompatible alloying elements have been prepared to investigate the effect of Zr content on β → α phase transformation, microstructure and mechanical properties. The study showed that element Zr stablized the β phase and that its effect on β phase transus exhibited a “margin effect”. With increasing Zr content, the microstructure of the Ti–Nb–Zr alloy was refined and the strength of ternary Ti–Nb–Zr alloys was also improved while the plasity significantly decreased. The Ti 72Nb 25Zr 3 alloy exhibited the maximum ultimate tensile strengh of 775 MPa and Ti 73Nb 25Zr 2 exhibited the lowest elastic modulus of 62 GPa. The low elastic modulus of Ti 73Nb 25Zr 2 was attributed to the formation of stress-induced martensite (α″ phase).