Thermal and non-thermal effects of Cu/Al laminated composite during electrically assisted tension

Abstract

The electrically assisted (EA) forming technology is expected to further explore the forming potential of Cu/Al laminated composite (LC). However, the current action mechanism in the forming process of Cu/Al LC is still unclear. In this paper, the influence mechanism of thermal effect and non-thermal effect on the dislocation structure of Cu/Al LC during EA tensile process was mainly studied. The results demonstrated that there was an obvious non-thermal effect in EA tensile Cu/Al LC. The flow stress reduction of EA tensile specimens was more significant than that of thermal assisted tensile specimens at the matching temperature. At the same time, the dislocation generated by the Frank-Read dislocation source and the Lattice distortion degree near the Frank-Read source was decreased by electric current. The decrease of dislocation density caused by the annihilation of the dislocations in the EA tensile process leads to the reduction of flow stress in the Cu/Al LC. In addition, the Cu matrix and the interface region dislocation lines of the EA tensile specimen were rearranged along the direction of electron movement and the crack tip healing in the intermetallic compound layer was promoted. What is more, the junction of phase layer becomes a new crack source due to the resistance being higher at the heterogeneous junction.