Effect of Cold Rolling and Aging on the Microstructure and Mechanical Properties of Ti-Nb-Zr Alloy

The effect of cold rolling deformation and aging treatment on the phase transformation, microstructure evolution, and mechanical properties of a new Ti-Nb-Zr metastable β-titanium alloy was investigated by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and mechanical property testing. The results show that the alloy exhibited excellent phase stability that no stress-induced α″ phase transition occurred during cold rolling and that the plastic deformation mechanism was related to dislocation slipping. Interestingly, even under the same aging treatment at 300 °C for 2 h, the aging products for the unrolled and cold-rolled alloys are β + ω and β + α, respectively. The alloy with cold deformation produces a large number of dislocation defects, and grain boundaries inhibit the nucleation of the ω phase, while the α phase tends to nucleate at the dislocations and grain boundaries and promote the precipitation of the α phase. Compared with solution treatment and aging, the aging treatment after cold deformation has high-strength matching and its ideal elastic modulus can satisfy the requirements for dental implants.