Effects of post-welded hot rolling on the properties of explosively welded Mg alloy/Al alloy cladding plates

The present study investigates the influence of post-weld hot rolling on the interfacial microstructure and mechanical properties of explosively welded Mg/Al alloy cladding plates fabricated with varying Mg alloy thicknesses. The as-welded joints exhibited a characteristic wavy interface, which became flattened after hot rolling, accompanied by the elimination of interfacial voids. In all samples, an interlayer was observed at the bonding interface. Prior to rolling, this interlayer consisted of a single magnesium-rich γ-Mg 17 Al 12 phase. After rolling, it transformed into a double-layer structure composed of γ-Mg 17 Al 12 and aluminum-rich β-Al 3 Mg 2 phases. Notably, the transformation of the interfacial phases was influenced by the initial Mg alloy thickness. Both tensile strength and ductility improved with increasing Mg alloy thickness. This study newly demonstrates that hot rolling is feasible even at 250 °C for explosively welded Mg/Al clads, which has rarely been reported in previous work. The tensile strength remained relatively stable across the tested temperatures (around 270 MPa), while the elongation decreased as the rolling temperature was reduced to 250 °C. These findings provide insight into the optimization of hot-rolled Mg/Al clads for lightweight structural applications.