Effect of Electropulsing on Microstructure and Properties of Severely Plastically Deformed Pure Copper Sheet

The plasticity of a material generally decreases after grain refinement by severe plastic deformation (SPD). In this paper, an energy-efficient electropulsing method is introduced to improve the plasticity of materials formed by the repetitive roll-bending and straightening (RRBS) process. The influence of the current density, frequency, pulse width and duration on the microstructure and properties of copper sheets that underwent SPD was experimentally investigated. The experimental results show that electropulsing reduced the hardness of the material, improved the plasticity and refined the grains. After the electropulsing treatment, the maximum elongation of the pure copper sheet that underwent a 20-pass RRBS process increased from 3.70 to 24.45%, and the average grain size was refined from 60 to 41 mu m. The electropulsing parameters, such as the current density and frequency, instantaneously changed the incoming current intensity into the samples and had a significant influence on the microstructure and properties of the materials. The thermal effect and the athermal effect impacted the dynamics and thermodynamics of the materials, which promoted the movement of dislocations, causing significant changes in the microstructure and properties of the material in a short time.