Investigation of coordinated behavior of deformation at the interface of Cu–Al laminated composite

To understand the differences between the microstructure and stress states owing to uncoordinated deformation in different regions of a Cu–Al contact interface, the normal stress distribution at the contact interface of the Cu–Al composites and the Al metal adhesion on the peeling surface of the Cu layer are investigated by performing numerical simulations and experimental studies. The results show that the percentage of Al metal adhered to the Cu side gradually increased from the edge to the central region. This is mainly because the central area of the contact interface bore a larger normal stress than the edge position, and when the interface normal stress exceeded 470 MPa, the pressure threshold value required for the extrusion of virgin metal from the surface-hardened layer on the Al side was satisfied. The effect of the initial Cu:Al thickness ratio on the degree of interfacial coordination is investigated, and the degree of coordination of the contact interface was observed to improve and then worsen with the increase in the initial Cu:Al thickness ratio (from 3:9 to 8:4). For composites with a Cu:Al thickness ratio of 4:8, the interface was well coordinated, and the bond strength reached 6.13 MPa, corresponding to a 173.7% improvement compared with the Cu–Al composite with more severe stress concentration (8:4).