Ti–Mo–Zr alloys for bone repair: mechanical properties, corrosion resistance, and biological performance

Titanium (Ti) alloys have been widely used as bone implants, but challenges such as the stress shielding effect still compromise long-term clinical successes. To improve the mechanical properties of Ti, non-toxic alloying elements zirconium (Zr) and molybdenum (Mo) were added either alone or in combination to produce Ti–Mo–Zr alloys. The influence of Zr or Mo addition on the alloy properties, such as the microstructure and the corrosion resistance, were investigated. The cytocompatibility and osteointegration of prepared alloys were evaluated to determine the potential for bone repair. The results showed that Ti–10Zr displayed an acicular α′ phase, while Ti–12Mo and Ti–12Mo–10Zr comprised a metastable β phase. Due to the solid solution and phase precipitation strengthening effect of Zr and Mo elements, the prepared alloys showed higher microhardness and compressive yield strength when compared with commercially pure Ti (CP–Ti). Ti–12Mo–10Zr possessed the lowest Young's modulus, while CP-Ti and Ti–10Zr showed a comparable Young's modulus. The corrosion resistance was in the order of Ti–12Mo–10Zr > Ti–12Mo > CP-Ti > Ti–10Zr. Notably, all alloys showed good cytocompatibility and osteointegration, which were similar to those of CP-Ti. Taken together, due to excellent material and biological performance, Ti–12Mo–10Zr presents a promising material for bone repair.