Fatigue performance and cyto-toxicity of low rigidity titanium alloy, Ti–29Nb–13Ta–4.6Zr

Abstract

A β type titanium alloy, Ti–29Nb–13Ta–4.6Zr, was newly designed and developed for biomedical applications. The new alloy contains non-toxic elements such as Nb, Ta, and Zr. In the present study, phases that appeared in the new alloy through various aging treatments were characterized by hardness tests and microstructural observations in order to identify the phase transformation. Fatigue properties of the new alloy were investigated. Young’s modulus and cyto-toxicity of the new alloy were also evaluated. Precipitated phases distribute homogeneously over the whole specimen, and they are α phase, a small amount of ω phase, and β phase when the new alloys are subjected to aging treatment at 673 K for 259.2 ks after solution treatment at 1063 K for 3.6 ks. The fatigue strength of the new alloy subjected to aging at 673 K for 259.2 ks after solution treatment at 1063 K for 3.6 ks is much better than when subjected to other aging treatments. In this case, the fatigue limit is around 700 MPa. Young’s modulus of the new alloy is much smaller than that of Ti–6Al–4V ELI. The cyto-toxicity of the new alloy is equivalent to that of pure Ti. Therefore, it is proposed that the new alloy, Ti–29Nb–13Ta–4.6Zr, will be of considerable use in biomedical applications.