Interfacial bonding characteristics and mechanical properties of H68/AZ31B clad plate

Interfacial bonding, microstructures, and mechanical properties of an explosively-welded H68/AZ31B clad plate were systematically studied. According to the results, the bonding interface demonstrated a “wavy-like” structure containing three typical zones/layers: (1) diffusion layer adjacent to the H68 brass plate; (2) solidification layer of melted metals at the interface; (3) a layer at the side of AZ31B alloy that experienced severe deformation. Mixed copper, CuZn₂, and α-Mg phases were observed in the melted-solidification layer. Regular polygonal grains with twins were found at the H68 alloy side, while fine equiaxed grains were found at the AZ31B alloy side near the interface due to recrystallization. Nanoindentation results revealed the formation of brittle intermetallic CuZn₂ phases at the bonding interface. The interface was bonded well through metallurgical reactions due to diffusion of Cu, Zn, and Mg atoms across the interface and metallurgic reaction of partially melted H68 and AZ31B alloys.