The microstructure and mechanical properties of copper in electrically assisted tension

Abstract

This study focuses on the mechanical behavior and microstructure evolution of oxygen-free high conductivity copper in the presence of electropulse. The result shows the tensile strength and strain-to-failure decrease linearly with the increase of pulse frequency, and the fracture mode changes from ductile to brittle. With the increase of pulse frequency, the grain size increases, the reduction of cross section decreases firstly and then increases. The increase of temperature due to applying of electropulse is considered as the main reason for the retardation of mechanical property and the change of fracture mode. Copper sulfide is found on the fracture surface, which may be the root cause for the electricity-induced embrittlement. Recrystallization induced by the presence of electricity inhibits the embrittlement and improves the plasticity of material. For undeformed copper, direct electrically assisted forming processing will decrease its plasticity, by contrast, for heavily deformed the copper, electrically assisted forming can reduce the flow stress and improve the plasticity.