Effect of Nb Content on Deformation Textures and Mechanical Properties of Ti-18Zr-Nb Biomedical Alloys

Abstract

Recently, β-type Ti alloys composed of non-toxic elements such as Nb, Ta, Zr, Mo and Sn have been studied for biomedical applications. The present author’s research group has also developed these alloys including Ti-Zr-Nb as new biomedical superelastic materials. They reveal strong textures which are formed during thermo-mechanical processing and cause the anisotropy in mechanical properties. In this study, the effect of Nb content on the deformation texture of Ti-18Zr-Nb alloys was investigated. The anisotropy in mechanical properties of Ti-18Zr-Nb alloys was also investigated. Ti-18Zr-(15∼18)Nb (at%) alloy ingots were fabricated by an Ar arc melting method and then homogenized at 1273 K for 7.2 ks. The ingots were cold rolled with a reduction up to 99% in thickness. For the as-rolled alloys, a weak γ-fiber texture was observed in Ti-18Zr-(15, 16)Nb alloys, whereas a well developed {001}⟨110⟩ texture was confirmed in the Ti-18Zr-18Nb alloy. The former alloys revealed weak anisotropy in Young’s modulus due to the weak texture, while the latter alloy exhibited strong anisotropy due to the strong texture.