Effect of Nb content on the microstructure and mechanical properties of binary Ti-Nb alloys

Abstract

The conventional titanium-based alloys, Ti-6Al-4 V in particular, have shown biological toxicity and mechanical incompatibilities which leads to implant loosening eventually requiring revision surgery. For that reason, there has been a growing interest in the development of new generation β-titanium biomedical alloys with improved mechanical properties specifically a lower Young’s modulus and enhanced biocompatibility. Therefore, this study aims to analyze the influence of Nb content on microstructural evolution and tensile properties of Ti-Nb alloys. Ti-Nb alloys containing 13 and 28 wt% Nb were cast using the vacuum arc remelting process. Microstructural changes were evaluated using the optical microscopy (OM) and scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDX). Phases present were determined by means of X-ray diffraction (XRD). The Vickers micro-hardness and tensile tests were performed to determine the mechanical properties of the Ti-Nb binary alloys. Experimental findings indicate that the microstructural and mechanical properties of the as-cast Ti-Nb alloys are both sensitive to Nb content. With increased Nb content, the microstructure evolved from the martensitic structure to the β-phase whereas the yield strength, ultimate tensile strength, and Young’s modulus all decreased and conversely, the micro-hardness increased.