Variety of Aluminum/Steel Interface Microstructures Formed in Explosively Welded Clads Followed by the Weld’s Thermal Expansion Response

This study presents a detailed analysis of the interface zone microstructure formed during explosive welding of aluminum alloy A1050 with S355J2N steel. The A1050 flyer plate was shot onto the base material carbon steel plate of improved strength and weldability. Aluminum alloy is characterized by very good resistance to atmospheric corrosion and high thermal and heat conductivity. Therefore, their combination brings about very good mechanical properties, especially high strength as well as improved corrosion resistance, which makes these materials potential candidates as an anode for active electrochemical corrosion protection applications. To characterize the microstructure of the welds, the observations were carried out by means of scanning and transmission electron microscopy techniques. Investigations performed on the cross sections allowed to study the interface morphology, as well as the microstructural changes of the joined materials in the vicinity of the bonding zone both at the micro- and nanoscale. The analysis of the results presented in the paper shows that within the wavy interface characteristic zones can be identified-melted regions and apparently sharp interface. The examined complex microstructures were composed of solid solutions, intermetallic phases, and quasicrystals. Moreover, for the first time, the thermal expansion measurements of A1050/S355J2N explosively welded platers were carried out.