Phase constitution, Mechanical Property and Corrosion Resistance of the Ti-Nb Alloys

Recently, people devote to the development of Ni-free shape memory alloys in order to avoid the Ni-hypersensitivity and toxicity and pursue absolute safety. The shape memory effect and superelasticity have been reported in the biomedical Ti-Nb based alloys. The purpose of this paper is to report the phase constitution, tensile property, shape memory effect and corrosion resistance of the Ti-Nb alloys. The phase constitutions of the Ti-Nb alloys are investigated by means of X-ray diffraction (XRD). The results reveal that β+α′′ phases are presented in the Ti-35Nb alloy and only β phase in the Ti-52Nb alloy at room temperature. The tensile test and bending tests indicate that the Ti-35Nb alloy exhibits shape memory effect. The shape recovery ratio is near to 80% when the bending strain is 4.4% and decreases with the increase of the total bending strain. The corrosion resistance of the Ti-Nb alloys in the Hank's solution and artificial saliva (pH=7.4) at 37
are investigated by OCP, Tafel and anodic polarization methods. The results indicate that the Ti-35Nb alloy has a better corrosion resistance in the artificial saliva and can replace the Ti-Ni alloy in the dental application. In the non-oral condition, the Ti-52Nb alloy may be preferable.