Joint effect of Zr and Cu on the properties of new powder metallurgy Ti–Zr–Cu alloys

Abstract

The performance of Ti alloys are directly related to their composition, where Zr and Cu are generally used, respectively, because of their non-toxic and antibacterial behaviour. As not previously reported in literature, this study considered the joint effect of Zr and Cu on the processing and properties of Ti, where Ti–Zr–Cu alloys were manufactured via powder metallurgy. It was found that Zr and Cu decrease the compressibility (86.5–88.05%), and Zr hinders whilst Cu boosts densification; therefore, the Ti–Zr–Cu alloys achieved higher relative sintered compact density values (93.6–94.5%) compared to sintered pure Ti (93.5%). Adding Zr and Cu changes the microstructure to lamellar, and their incremental addition refines the microstructure and leads to the formation of a eutectoid (sub)structure. As the amount of Zr and Cu increases, the Ti–Zr–Cu alloys become stronger (YS: 365–792 MPa, and UTS: 447–849 MPa) and less ductile (1.6–13.7%). However, they still primarily fail in a ductile manner, due to the microstructural changes (e.g. smaller interlamellar spacing) and strengthening effects (e.g. solid solution) brought about by the incremental addition of the alloying elements.