Influence of Nb addition on microstructural evolution and compression mechanical properties of Ti-Zr alloys

In order to expand the application horizon of Ti-Zr based alloys, the influence of Nb content on phase composition, microstructural evolution and biomechanical properties is systematically studied. The phase and microstructural characterization of the as-cast alloys is carried out by X-ray diffraction, optical microscopy and transmission electron microscopy. The results reveal that Nb-containing Ti-Zr alloys transformed from single alpha phase -> alpha + alpha '' + beta phase -> single beta phase -> double beta phases with increasing Nb content. In the case of beta-type alloys, the addition of Nb improves the bonding energy between atoms, reduces the grain size, increases the elastic modulus, improves the yield strength and renders superior work-hardening behavior. Moreover, the current study provides mechanistic insights into microstructural evolution and strengthening of Nb-containing Ti-Zr alloys with increasing Nb content. Herein, the addition of 5 at.% Nb resulted in an abnormal work hardening during compression deformation under the synergistic influence of stress-induced martensite transformation of beta phase and stress-induced twinning of alpha phase. Moreover, the biomechanical properties are evaluated to demonstrate the potential of Nb-containing Ti-Zr alloys in biological applications. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.