A Dynamic Recrystallization (DRX) Constitutive Model for Elevated Temperature Flow Behavior of Cu-0.5Cr-0.1Zr Alloy

Abstract

In order to obtain the high-temperature flow behavior of Cu-0.5Cr-0.1Zr alloy more accurately, the hot compression test of Cu-0.5Cr-0.1Zr alloy was performed at the strain rates from 0.001 to 1.0 s−1 and the deformation temperatures from 600 to 750 °C on a Gleeble-3800 thermo-simulation machine. The results show that the high-temperature flow stress and dynamic recrystallization behavior of Cu-0.5Cr-0.1Zr alloy are affected by strain rate and temperature. The peak stress is obvious under the condition of high temperature and low strain rate, and the flow stress curve shows a clear dynamic recrystallization phenomenon. On the contrary, there is no obvious peak stress at the low temperature and high strain rate, and dynamic softening behavior is mainly based on dynamic recovery. The high-temperature flow stress of Cu-0.5Cr-0.1Zr alloy is expressed as a result of multiple stress actions, such as work hardening, dynamic recovery softening, and dynamic recrystallization softening. The thermal deformation activation energy of this alloy can be calculated as 244.94 kJ/mol. The relationship between the critical stress and the critical strain of dynamic recrystallization and the Z parameter was established through the cubic linear fitting of the work hardening rate curve. Based on the stress–dislocation relation and kinetics of dynamic recrystallization, the constitutive equations before and after critical strain of Cu-0.5Cr-0.1Zr alloy were developed. The predicted stresses of the established DRX constitutive model agree well with the experimental stresses.