Interface microstructure and corrosion resistance of T2 Copper/6061 aluminum composites produced by explosion welding under different explosive loads

Cu/Al composites have many potential applications because they combine good thermal conductivity of Cu with low density of Al and offer both high strength and good corrosion resistance. However, they are prone to the formation of brittle intermetallic compounds (IMCs) at the Cu/Al interface, which can seriously compromise the mechanical properties and corrosion resistance of the material. In this study, Cu/Al composites were fabricated by explosion welding, and the effects of explosive load on the interface microstructure, hardness and corrosion resistance were investigated. The results show that when the thickness of the explosive was increased from 16 mm to 20 mm and then to 24 mm, the thickness of the IMC layer was increased from 35 μm to 38 μm, and to 70 μm, and the maximum interface hardness was increased from 399.6 HV to 603.1 HV, and then to 612.8 HV. The sample produced under the explosive load of 20 mm thickness exhibited better overall corrosion resistance, due to the formation of CuAl 2 in the interface region, which has a denser structure and higher stability than CuAl 3 . With prolonged immersion time in 3.5 wt% NaCl solution, the corrosion rate first increased, then decreased, and then increased again, due to the sequence of increased electrochemical activity, formation of a dense passivation film, and rupture of the corrosion product layer as the immersion corrosion progressed.