Improvement of Superelastic Performance of Ti-Nb Binary Alloys for Biomedical Applications

Recently, beta-Ti-based alloys consisting of non-cytotoxic elements and possessing a low elastic modulus attracted considerable attention for biomedical applications. In addition to low elastic modulus, these alloys must also present a high strength level required to endure stresses. However, it is not easy to find a thermomechanical route in order to achieve low elastic modulus and high strength simultaneously. In this study, we show that severe cold-rolling deformation followed by a short aging treatment on Ti-Nb binary alloys, in order to produce ultrafine grains and/or omega phase, is an effective way to improve both strength and superelasticity. High stress (900 MPa), low modulus (35 GPa), and high recoverable strain (2.5%) are obtained using this route. The obtained results on mechanical properties are explained in relation with microstructure evolution during thermomechanical processing.