Tribological Performance and Electrochemical Behavior of Ti-29Nb-14Ta-4.5Zr Alloy in Simulated Physiological Solution

Herein, the tribological performance and in vitro electrochemical behavior of Ti-29Nb-13Ta-4.6Zr (TNTZ) reinforced by various nanosized phases are investigated. The various microstructures-1) single beta-phase, 2) beta + alpha '' martensite, 3) beta + omega, and 4) beta + alpha-are prepared through purposeful heat treatment and subsequent aging. Sliding wear tests are performed under the applied load of 5 N and sliding speed of 0.3 mm s(-1) against Ti-6Al-4V extra-low interstitial alloy. Wear performance of the heat-treated alloys significantly improves compared with the solution-treated state, where the beta + omega microstructure possesses the lowest weight losses. In fact, the precipitation of the nonsharable hard nanophase improves plastic shear resistance of the subsurface and in turn prohibits premature crack initiation. Such a supporting effect of the subsurface layer also increases the stability of the superficial oxide layer and decreases the amount of metallic/oxide debris. The electrochemical performances of the elaborated microstructures are assessed through potentiodynamic polarization and electrochemical impedance spectroscopy in the simulated body fluid. Interestingly, the beta + omega alloy exhibits the extraordinary corrosion resistance compared to other structures. This is attributed to the uniform distribution, spherical morphology, and coherent interface of the omega-nanoprecipitates.