Microstructure and mechanical properties of Ti-Zr alloys fabricated by two-step spark plasma sintering from TiH2 and ZrH2 powders

Ti is well-known for its high strength-to-weight ratio and biocompatibility. It can be alloyed with Zr to improve mechanical properties. Currently, Ti-Zr alloys can be fabricated by powder metallurgy using Ti and Zr powders, although high oxidation reactivity and cost could still be an issue. In this study, premixed TiH2 and ZrH2 powders were used to prepare Ti-Zr binary alloys with different Zr contents of 0–30 mass% ZrH2 via dehydrogenation and sintering by spark plasma sintering (SPS) process. α-Ti and δ-TiH2 phases coexisted in the sintered Ti-Zr alloys, and a characteristic lamellar microstructure was formed. The tensile strength of the Ti-Zr alloys increased with increasing Zr content due to the solid solution effect, grain refinement and the appearance of δ-TiH2 phases, although the elongation was reduced. This study shows that the fabricated Ti-Zr alloys possess controllable mechanical properties, which can be beneficial for biomedical and other engineering applications.