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

Abstract 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 α phase → α + α" + β phase → single β phase → double β phases with increasing Nb content. In the case of β-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 β phase and stress-induced twinning of α phase. Moreover, the biomechanical properties are evaluated to demonstrate the potential of Nb-containing Ti-Zr alloys in biological applications.