Compression Deformation Behavior and Processing Map of Pure Copper

To reveal the compression deformation behavior of pure copper, the deformation characteristics of pure copper have been investigated by means of compression tests in the temperature range of 400–900°C and strain rate range of 0.001–1 s^–1. The results show that the flow stress of pure copper increases with strain rate and decreasing deformation temperature, which is characterized by work-hardening, dynamic recovery, dynamic recrystallization, secondary work-hardening, etc. The activation energy of hot deformation is associated with deformation temperature and strain rate, and the average activation energy is calculated to be 303.8 kJ/mol. The flow stress prediction model based on GA+BP network provides a very good agreement with the true stress curve, which is instrumental for the guidance of hot working of pure copper. The flow instability occurs in the intermediate strain rate range (0.01–0.1 s^–1). Based on the processing map anakysis, the high power dissipation corresponds to the dynamic recrystallization. Appropriate reduction of the deformation temperature or increased strain rate are beneficial for the grain refinement in the steady-state range of the processing map.