Formation Sequence of Interface Intermetallic Phases of Cold Rolling Cu/Al Clad Metal Sheet in Annealing Process

The formation Gibbs energy of the intermetallic phases at the interface of cold rolling Cu/Al clad metal sheet in annealing process was calculated theoretically. The concept and the calculating method of effective formation Gibbs energy which can predict the formation sequence was proposed. By the means of that theory, the calculated formation sequence of the intermetallic phases at 200-300 was worked out for the cold rolling Cu/Al clad metal sheet in annealing process, i.e. Al2Cu (Al side), AlCu (mid-layer) and Al4Cu9(Cu side). Besides, the boundary layer organizational microstructure of the composite material was analyzed by the means of SEM and XRD. As a result, the annealing temperature is the primary factor which affects the formation of the intermetallic phases of the cold rolling Cu/Al clad metal sheet, while the holding time is the second one. The observed formation sequence of the intermetallic phases of cold rolling Cu/Al clad metal sheet on annealing temperature 250-300 was: Al2Cu (Al side), Al4Cu9(Cu side) and AlCu (mid-side).