Microstructures and mechanical properties of a new titanium alloy for surgical implant application

Abstract

A new titanium alloy Ti12.5Zr2.5Nb2.5Ta (TZNT) for surgical implant application was synthesized and fully annealed at 700°C for 45 min. The microstructure and the mechanical properties such as tensile properties and fatigue properties were investigated. The results show that TZNT mainly consists of a lot of lamella α-phase clusters with different orientations distributed in the original β-phase grain boundaries and a small amount of β phases between the lamella α phases. The alloy exhibits better ductility, lower modulus of elasticity, and lower admission strain in comparison with Ti6Al4V and Ti6Al7Nb, indicating that it has better biomechanical compatibility with human bones. The fatigue limit of TZNT is 333 MPa, at which the specimen has not failed at 10⁷ cycles. A large number of striations present in the stable fatigue crack propagation area, and many dimples in the fast fatigue crack propagation area are observed, indicating the ductile fracture of the new alloy.

Keywords

titanium alloy / surgical implant / microstructure / mechanical properties / fatigue

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