Assessment of improved tribocorrosion in novel in-situ Ti and ? Ti-40Nb alloy matrix composites produced with NbC addition during arc-melting for biomedical applications

Nontoxic and nonallergenic beta-type Ti-Nb alloys are considered attractive metallic materials for long-term bone implant applications. However, metallic implants present poor wear resistance, and the degradation process can be intensified with the friction occurring in corrosive body fluids, such as joint prostheses. The present study aimed to improve the tribological behavior of Ti-Nb alloys by adding hard reinforcement. The applied strategy is based on in-situ conditions, in which the reinforcing phase can be synthesized during the fabrication of the composite. Thus, a strong interfacial bond can be achieved due to the high chemical compatibility between the matrix and the reinforcement. Therefore, two different in-situ composites were developed by adding NbC powder to Ti and beta Ti-40Nb alloy during the arc-melting process. As-cast samples of Ti and beta Ti-40Nb alloy without NbC were used as the control groups. Structural characterization was performed, along with corrosion and tribo-corrosion tests in a phosphate-buffered solution at body temperature. Results demonstrated that in-situ reactions occurred during the arc-melting process and promoted the precipitation of TiC as the reinforcing phase sur-rounded by alpha Ti phase (when NbC was added to Ti), and by beta Ti-Nb phase (when NbC was added to Ti-40Nb). Finally, both produced composites showed improved tribocorrosion behaviors with wear volumes less than half of that recorded by the unreinforced Ti and beta Ti-40Nb alloy. Thus, this study presents promising alternatives for wear-resistant biomedical applications.