Hot Deformation Behavior and Microstructure Evolution of Near-α Titanium Alloy TA32 in Dual-Phase Zone

The hot deformation behavior of the near-α titanium alloy TA32 (Ti-5.5Al-3.5Sn-3Zr-1Mo-0.5Nb-0.7Ta-0.3Si) was studied by isothermal compression tests. The deformation temperatures ranged from 700 to 950 °C, with strain rates ranging from 0.001 to 1.0 s⁻¹. The stress-strain curves corresponding to different deformation parameters were studied to evaluate the mechanical behavior. A prediction model of peak stress of TA32 titanium alloy in the dual-phase zone was established, utilizing friction-temperature-corrected flow stress. Electron backscatter diffraction (EBSD) and scanning electron microscopy (SEM) were used to examine the influence of deformation parameters on microstructure evolution. The findings reveal that at 950 °C and 0.01 s⁻¹, the recrystallized volume fraction reaches 34.6%, with an average recrystallized grain size measuring 3.03 μm, which is significantly enhanced compared with those at lower deformation temperatures. By examining the softening behavior across different deformation parameters, it was concluded that dynamic recrystallization (DRX) becomes the primary mechanism. The conclusions of this study can provide some reference and guidance for the microstructure evolution of TA32 alloy during the hot deformation process so as to accelerate the design and optimization of deformation process parameters and the development and popularization of a new high-temperature titanium alloy TA32.