Preparation and characterization of metastable β-type titanium alloys with favorable properties for orthopedic applications

Abstract

Titanium (Ti)-based alloys with good mechanical properties are highly desirable for bone implants to achieve long-term clinical success. As non-toxic alloying elements, zirconium (Zr) and molybdenum (Mo) have been employed to improve the mechanical properties of Ti-based alloys. In this work, a series of Ti-Zr-Mo alloys, including Ti-18Zr, Ti-13Mo, and Ti-18Zr-13Mo were prepared and compared for potential orthopedic applications for the first time. The phase composition, microstructure, mechanical properties, corrosion resistance, biocompatibility, and osteointegration performance were systemically investigated. It is found that Ti-18Zr displayed an acicular α′ phase, whereas Ti-13Mo and Ti-18Zr-13Mo exhibited a metastable β phase. Compared with commercially pure Ti (CP-Ti), the prepared Ti-Zr-Mo alloys possessed a higher compressive yield strength and a greater microhardness, because of the solid solution and phase precipitation strengthening of Zr and Mo elements. Furthermore, Ti-18Zr-13Mo and Ti-13Mo demonstrated better corrosion resistance than that of CP-Ti, while Ti-18Zr exhibited an inferior result. The cytocompatibility and osteointegration of prepared alloys were similar to those of CP-Ti. Taken together, the Ti-Zr-Mo alloys investigated in this study present a promising alternative to CP-Ti for orthopedic applications, among which the metastable β-type alloy Ti-18Zr-13Mo is most attractive. Moreover, an appropriate Mo content enhances the mechanical and corrosion resistance properties of Ti-based alloys, whereas a high Zr content may pose an adverse influence on the corrosion resistance, which provides valuable insights into the design and further optimizing of new Ti-Zr-Mo alloys for future biomedical applications.