Ti-Mo alloys employed as biomaterials: Effects of composition and aging heat treatment on microstructure and mechanical behavior

The correlation between the composition, aging heat treatments, microstructural features and mechanical properties of beta Ti alloys is of primary significance because it is the foundation for developing and improving new Ti alloys for orthopedic biomaterials. However, in the case of Ti-Mo alloys, this correlation is not fully described in the literature. Therefore, the purpose of this study was to experimentally investigate the effect of composition and aging heat treatments on the microstructure, Vickers hardness and elastic modulus of Ti-Mo alloys. These alloys were solution heat-treated and water-quenched, after which their response to aging heat treatments was investigated. Their microstructure, Vickers hardness and elastic modulus were evaluated, and the results allow us to conclude that stabilization of the beta phase is achieved with nearly 10% Mo when a very high cooling rate is applied. Young's modulus was found to be more sensitive to phase variations than hardness. In all of the compositions, the highest hardness values were achieved by aging at 723 K, which was attributed to the precipitation of alpha and omega phases. All of the compositions aged at 573 K, 623 K and 723 K showed overaging within 80 h. (c) 2014 Published by Elsevier Ltd.