Rolling strain effects on the interlaminar properties of roll bonded copper/aluminium metal laminates

Metal laminates of copper/aluminium were prepared by roll bonding at 430°C with various rolling strains. The effect of the rolling strain on the interface development and bond strength of the laminates was examined. It was found that as the rolling strain increased the bond strength of the laminates was generally enhanced in both as-rolled and sintered conditions. Critical post-rolling sintering conditions were found to exist for achieving optimum bond strengths of the laminates. It is evident that the development of optimum strength for the laminates is related to the formation of various intermetallic phases at the interface which is in turn determined by the diffusion activity of the metallic elements in the area. The greatest strength enhancement was generally observed to develop in the 60% rolled samples, suggesting that rolling strain of the roll bonding process may impose great influence on diffusion of the metallic elements. A higher copper content, without significant Kirkendall void formation, was found to build up in the interface area of the material, leading to development of strong interfacial phases. It is believed that a higher rolling strain of the roll bonding process has provided a greater area of physical contact between the bonded metals and imposed diffusion enhancement of the metallic elements across the interface.