A comparative study on corrosion and wear performances of Ti-Nb-(Cu, Co) biomedical shape memory alloys

The present study presented the systematic investigations on the influence of Co and Cu on the corrosion behaviors and wear resistance of Ti-Nb based shape memory alloys. The results demonstrated that the addition of Co and Cu can effectively enhance the corrosion resistance of Ti-Nb based shape memory alloys. By optimizing the chemical composition, the superior corrosion resistance with (phi(corr) = -0.95499 V, J(corr) = 357.92 mu A cm(-2)) and (phi(corr) = -0.96775 V, J(corr) = 467.54 mu A cm(-2)) can be obtained in Ti-Nb-Co-1.0 and Ti-Nb-Cu-1.5 shape memory alloys, respectively. Similarly, the wear properties of Ti-Nb based shape memory alloys were also dependent on the ternary alloying elements. The friction coefficient of Ti-Nb based shape memory alloy firstly decreased and then increased with the content of ternary alloying element increasing. And then decreased again, as the exceeding ternary alloying element was added. In addition, the wear behaviors of Ti-Nb based shape memory alloys can be attributed to the combination of abrasive wear, adhesive wear, and oxidative wear, irrespective of the types of ternary alloying elements. In contrast, Ti-Nb-Cu-5.0 shape memory alloy has the lowest friction coefficient of 0.45, which is smaller than that (0.50) of Ti-Nb-Co-5.0 shape memory alloy.