Microstructure and Mechanical Properties of 2219 Aluminum Alloy/T₂ Copper Explosively Welded Composite Plate

In this paper, the 2219 aluminum alloy / T₂ copper composite plate with good properties and almost no metallurgical defects was obtained by the explosive welding method. Meanwhile, its microstructure and mechanical properties were systematically studied. In terms of microstructure, two typical morphologies of local melting zone and vortex structure around the interface of the composite plate can be observed and both morphologies represented brittle-hard Al-Cu intermetallic compound regions. The interface of the composite plate mainly included Al₂Cu and Al₄Cu₉ intermetallic compound layers. The Al₄Cu₉ layer had a typical {001} texture with the smaller grain size, the lower dislocation density and the lower energy. In terms of mechanical properties, the tensile strength of the composite plate reached 55% of the aluminum alloy cladding material and 70% of the copper substrate material, respectively. The composite plate fractured in the order of aluminum alloy, interface, copper and showed brittle fracture characteristics in the crack initiation region. The brittle-hard second phases in the aluminum alloy matrix were extremely unfavorable to the mechanical properties of the composite plate.