Influence of Interfacial Structure Development on the Fracture Mechanism and Bond Strength of Aluminum/Copper Bimetal Plate

The aim of this article is to study the influence of interfacial structure development at interface on the fracture mechanism and the bond strength of cold roll bonded Al/Cu bimetal plate. The Al/Cu bimetal plates are produced by cold roll bonding and then sintered at different conditions. The bond strength of the Al/Cu bimetal plate increases generally to maximum values and then decreases to low values with increasing sintering temperature and time. Interfacial structures develop with increasing sintering temperature and time. The main interfacial layers are Al2Cu, AlCu, Al3Cu4 and Al4Cu9. The formation and thickening of those intermetallic compounds promotes cracks propagation and weakens the bond strength of the bimetal plates. The fracture mechanism transforms from ductile to brittle cleavage with the development of interfacial structures. While the bond strength of the material starts to decrease, no obvious Kirkendall effect of void formation is observed in the present study.