Electropulsing-enhanced atomic diffusion and recrystallization to optimize mechanical properties of Al/Cu laminated metal composites

Abstract

This work adopted the combined processing of electropulsing bonding (EPB) and electropulsing rolling (EPR) to prepare high-performance Al/Cu laminated metal composites (LMCs). The results show that electropulsing (EP) significantly accelerates the diffusion of Al and Cu atoms, thus facilitating the formation of diffusion layer. Through EP treatment, the recrystallization behavior of the Al and Cu layers is enhanced. The microstructure composed of a diffusion layer with suitable thickness and fine recrystallized grains contributes to the mechanical properties. Due to the introduction of intermetallic compounds (IMCs), the hardness and elastic modulus of Al, Cu, and diffusion layers exist large differences. The hard diffusion layer can exert a rigid deformation constraint on the ductile Al and Cu layers, and promote the interface deformation. Meanwhile, the tensile strength of as-EPRed samples increases and then decreases with the increasing EP frequency, the maximum is ∼215.2 MPa at 20 kHz. Theoretical analysis indicates that the local Joule heating and athermal effect should be the principal factors for microstructure evolution and property optimization. These results are expected to clarify the EP-related mechanism on atomic diffusion and recrystallization, which provides guidance for the fabrication of Al/Cu LMCs.