An AA5083 aluminum alloy plate and an SS41 steel plate were cladded by an explosive welding method using an AA1050 aluminum alloy interlayer plate. The effects of the interlayer thickness on the interface morphology and the shear deformation behavior of the cladded plates were studied. The interfacial zone was composed of an intermetallic compound, FeAl3, formed by the AA1050 interlayer. The intermetallic compound acted as a crack source at the AA1050/SS41 interface, and the thickness and morphology of the interfacial zone were depended on the thickness of the AA1050 interlayer. In a shear deformation test, the crack propagation behavior varied according to the morphologies of the interfacial zone, and the shear strength of the cladded plates decreased with the interlayer thickness. (C) 2003 Kluwer Academic Publishers.