Wear characteristics of Ti–Nb–Ta–Zr and Ti–6Al–4V alloys for biomedical applications

The influences of heat treatment, variation in Nb content, surface modification and counterface materials on the wear characteristics of new β type Ti–Nb–Ta–Zr alloys and conventional metallic implant alloy Ti–6Al–4V were investigated, using a reciprocal pin-on-disc wear device in a 0.9% NaCl solution. For the wear test of sliding on stainless steel disc, experimental results show that the wear resistance of Ti–29Nb–13Ta–4.6Zr and Ti–6Al–4V is insensitive to their mechanical properties, such as hardness and ultimate tensile strength. Increase in Nb content results in an improvement of the wear resistance of the β type alloy to some degree. The wear resistance of Ti–29Nb–13Ta–4.6Zr improved significantly after oxidation treatment, due to the presence of Nb2O5 oxide particles on the diffusion hardened surface of the alloy. For wear test of sliding on ultra-high molecular weight polyethylene (UHMWPE) and bone of pig, the wear losses of both Ti–Nb–Ta–Zr and Ti–6Al–4V are much less compared with that sliding on stainless steel and there is almost no wear on the surface of oxided Ti–29Nb–13Ta–4.6Zr.