Zr-bearing powder metallurgy binary Ti alloys: Fabrication and characterisation

Abstract

Zirconium is an ideal alloying element to be added to titanium for biomedical applications due to its non-toxic behaviour and high solubility. In literature, binary Ti–Zr alloys have primarily been manufactured via casting, while powder metallurgy has been partly ignored even though of its intrinsic advantages. Moreover, the tensile properties of Ti–Zr alloys, and so their work hardening behaviour, has not been properly understood. Consequently, this study investigated the effects that lean additions of Zr have on the microstructure and properties of powder metallurgy binary Ti–Zr alloys produced by uniaxial pressing plus sintering. It is found that the incremental addition of Zr reduces the compressibility and enhances the densification, resulting in comparable relative density values for different Zr contents. The addition of Zr leads to the formation of a lamellar microstructure, which is progressively refined by further addition of Zr. Therefore, the tensile strength and hardness increase with the incremental addition of Zr, while the ductility initially increases and then decreases. Although the studied Ti–Zr alloys have similar work hardening, their actual behaviour is directly dictated by the microstructural features.