Constitutive behavior and hot workability of multi-direction forged T2 copper during hot compression deformation

The hot deformation behavior of a multi-direction forged (MDFed) T2 copper was investigated by the isothermal compression test at deformation temperatures between 673 and 1173 K and strain rates between 0.001 and 10 s(- 1). The results reveal that the deformation characteristics of the flow stress are sensitive to the hot deformation parameters. The deformation activation energy of the MDFed copper under the test conditions was calculated as 195.601 kJ/mol. The constitutive behavior was described by a two-stage constitutive model, which is based on the stress-dislocation relation and kinetics of dynamic recrystallization (DRX). Based on the dynamic material model, the three-dimensional (3D) processing maps were established to identify the instability regions and optimal hot processing parameters. It is found that DRX occurred in all the stability and instability regions, and the optimal processing conditions are in the temperature range of 923-1023 K and strain rate range of 0.1-1 s(- 1), which indicates a feature of incomplete DRX. Moreover, the grains overgrew at high deformation temperatures and low strain rates, resulting in a poor workability for the MDFed copper.