Correlation between bonding strength and mechanical properties in Mg/Al two-ply clad sheet

The effect of interfacial bonding strength has been investigated in relation to mechanical properties of roll-bonded two-ply Mg/Al clad sheets in this study. Two types of thin reaction layers (Mg17Al12 and Mg2Al3 phase layers) were observed to form along the Mg/Al interface and their thickness was found to increase with annealing time. The maximum average bonding strength was achieved after annealing Mg/Al clad sheet for 10 min at 300 °C. The fracture strain of Mg alloy in this annealed clad sheet was found to increase up to 22.5% compared to 17.8% of monolithic AZ31 Mg alloy. In addition, the formability of clad Mg alloy was also found much higher compared to those of monolithic Mg alloy. This ductility enhancement of clad Mg alloy appears due to more prolonged homogeneous deformation, caused by delayed localized necking.