The study of deformation behavior and microstructure evolution in forged pure tantalum

In this study, the deformation characteristics of as-forged pure tantalum were investigated using a Gleeble-3800 thermal simulation testing machine in the temperature range of room temperature to 350 °C and strain rates ranging from 0.1 to 10 s−1, with a maximum deformation of 60 %. Results show that the deformation resistance increases with decreasing deformation temperature and increasing strain rate before reaching the peak stress. After reaching peak stress, deformation is dominated by dynamic recovery mechanisms. Based on the true stress-strain curves obtained from experiments, the deformation activation energy (Q) and stress exponent (n) of the material were calculated to be 5.133 kJ/mol and 3.1989, respectively. A constitutive equation describing the rheological behavior was established. Utilizing processing maps combined with post-deformation microstructures, optimal processing parameters were determined to be a deformation temperature of room temperature, a strain rate ranging from 3.5 to 10 s−1, and a dissipation rate of 0.12. Under these optimal processing parameters, the material microstructure mainly consisted of dynamically recrystallized grains and deformed grains. •The strain rate and deformation temperature significantly affect the flow stress of forged pure tantalum. Increasing the strain rate or decreasing the deformation temperature both result in an increase in flow stress.•Combining the compression test data and considering the influence of strain on the constitutive equation, we successfully established a constitutive equation with strain compensation.•The optimal processing parameter range for this material is determined to be at room temperature, with strain rates ranging from 3.5 s−1 to 10s−1, corresponding to a maximum power dissipation value of 0.12.•At room temperature, higher strain rates promote the occurrence of dynamic recrystallization (DRX), where the dynamic softening mechanism of the material is primarily composed of dynamic recovery (DRV) and partial DRX.