Hot deformation characteristics and kinetics analysis for Ni-based corrosion resistant alloy

The hot deformation characteristics of Nickel-based corrosion resistant alloy was studied in the temperature range of 1050°C to 1200°C and the strain rate range of 0.001 to 0.1 second⁻¹ by employing hot compression tests. The results show that the peak stress increases with decreasing temperature and increasing strain rate, and the apparent activation energy is about 409 kJ/mol. Based on the Avrami equation through using the critical strain (ε_c) and the strain for 50% DRX (ε_0.5), a kinetic model for dynamic recrystallization (DRX) was established, where the model parameters could be obtained using the modified Zener-Hollomon parameter (Z*). Applying the model, the predicted value of the steady-state strain (ε_ss) and the strain for maximum softening rate (ε_m) agree well with the experimental results. Accordingly, the relationship between ε_m and ε_0.5 is established, which is mainly dependent on the Avrami exponent (n). When n < 3.25, ε_m becomes less than ε_0.5 and the difference in between decreases with increasing the strain rate or decreasing the deformation temperature. Finally, through observing DRX microstructure under different deformation conditions, a power law relation between DRX grain size (D_drx) and Z*, with an exponent of −0.36, was found.