Fatigue and wear evaluation of Ti-Al-Nb alloys for biomedical applications

In this work the fatigue and wear behavior of Ti-15Al-33Nb(at.%) and Ti-21Al-29Nb(at.%) was evaluated and compared to that for other titanium-based biomedical implant alloys, in particular Ti-6Al-4V(wt.%). Fatigue stress versus life curves were obtained for tests performed at room temperature in air at a stress ratio of R = 0.1 for maximum stresses between 75%-90% of the ultimate tensile strength. The results indicated that the fatigue strength and lives of the as-processed alloys are comparable to that for Ti-6Al-4V(wt.%). Heat treatment significantly increased the orthorhombic-phase volume fractions in the alloys and resulted in reduced fatigue strength. The wear resistance for the alloys was significantly greater than that for Ti-6Al-4V(wt.%). Based on the current results, it is proposed that titanium-aluminum-niobium alloys will be of considerable future interest for biomedical applications.