Electroplastic Cyclic Deformation of CuZn30 Brass

This article presents the results of research on electrically assisted forming (EAF) in the process of cyclic oscillatory torsion of CuZn30 brass. Experiments were conducted using pulsed electric current with varying parameters: pulse durations of 0.5, 2.5, and 5 ms, and pulse intervals ranging from 0.5 to 30 ms. Reference data for the electrically assisted torsion tests were obtained from conventional tests performed under identical conditions without current flow. A pronounced thermal effect was observed for specific current parameters. To accurately determine the impact of temperature rise on the deformability of CuZn30 brass during cyclic torsion, the authors conducted additional tests at elevated temperatures-corresponding to the average temperatures recorded during the EAF trials-without current application. In all investigated cases, EAF during cyclic oscillatory torsion led to a flow stress reduction ranging from nearly 8% to almost 25% compared to current-free trials. Furthermore, applying current parameters where the pulse interval exceeded the pulse duration resulted in a significant increase in strain to failure, ranging from nearly 25% up to 110% relative to the reference samples. The study also examined isophase current characteristics (where pulse duration equals pulse interval), which yielded results that clearly deviated from other configurations. The application of isophase pulses triggered a different material response, leading to a degradation of deformability by more than 21%. The presented research and findings may contribute to the further development of novel, energy-efficient, and advanced manufacturing processes in metal forming.