The effects of oxide film and annealing treatment on the bond strength of Al–Cu strips in cold roll bonding process

• By providing Al2O3 film on Al strips, peel strength was firstly decreased.
• By increasing film thickness, peel strength was increased and then decreased.
• By decreasing the reduction, the peel strength was deteriorated for all samples.
• During peeling test, Al and alumina remained on the Cu peeled strips.
• By annealing the Al–Cu strips after CRB, bond strength was decreased markedly.

In this study the influence of Al2O3 coating and post-rolling annealing on the bond strength of dissimilar Al–Cu strips was investigated. For this purpose different degrees of thickness of Al2O3 film on Al strips were coated using anodizing process. Anodized aluminum and copper strips were then cold-rolled at different reduction levels. To investigate the effect of annealing treatment on bond strength after cold rolling, selected strips were annealed. Peeling test was used to investigate the effect of ceramic-based oxide film on bonding strength of Al–Cu strips. It was found that bond strength was improved after applying higher reductions and was decreased dramatically by providing oxide film. However, by increasing the thickness of oxide film up to a certain value (20 μm), bond strength was increased after which it was decreased. A decrease in bond strength was observed by post-rolling annealing.