Flow stress characteristics and microstructure evolution during hot compression of Nb-47Ti alloy

The thermal-deformation allows fast and efficient grain refinement and microstructure modification in medical Ti-Nb based alloys. To design compatible process parameters, a study was carried out to investigate the softening mechanism and microstructure evolution behavior in Nb-47Ti alloy at 660–910 °C with a strain rate range of 0.01-1s⁻¹. And then, based on the dislocation density evolution and kinetics of dynamic recrystallization, a physically-based constitutive model was established to predict the flow stress of the alloy. We showed that dynamic recovery is more active than dynamic recrystallization when the alloy is deformed below 810 °C. Meanwhile, recrystallized grains were observed over this temperature at low strain rate, i.e. lower than 0.1s⁻¹. The presented model was incorporated into Deform 3D to provide an effective means to verify the reliability of the hot deformation behavior. Results confirmed that the model provides high accuracy and the simulation work well by running in a view to DRX.