Abstract: The Al/Cu composite sheet was fabricated by means of accumulative pack-roll (ARB) incorporated with multiple annealing treatment and the core-shell structure formation mechanism of Al/Cu interfacial reaction layer was emphatically investigated. The result showed that atomic diffusion of copper at Al/Cu interface during annealing would play a key role in the formation of Al/Cu interfacial reaction layer and the resultants would include intermetallic compounds Al₂Cu, AlCu and Al₄Cu₉. The rolling deformation would make the reaction layer broken and distributed uniformly the matrix. The annealing treatment after rolling would lead to continuous formation of new interface reaction layer. Finally, after multiple pack-rolled pass and annealing treatment, the entire primary copper sheets would be transformed into axiolitic Al/Cu intermetallic compound particles with core-shell structure. The composite sheet after eight ARB passes would have highest ultimate tensile strength (UTS) of 176.8 MPa which would be 1.74 times of that of annealed 1060. The elongation of composite sheet without rolling would be better; this was basically due to that the aluminium layer would deform plastically and uniformly after Al/Cu interface delamination and the stress would slowly be released.

Key words: accumulative pack roll bonding (ARB), Al/Cu composite sheet, interface reaction layer, core-shell structure