Effect of secondary rolling on the interfacial bonding strength and mechanical properties of Al/Mg/Al clad plates

The effects of secondary rolling on the microstructure evolution and mechanical properties of Al/Mg/Al clad sheets have been investigated. The results indicate that a double-layer intermetallic compound (Mg2Al3 and Mg17Al12) forms and sandwiches the MgO film during the first rolling and annealing, while the sandwich structure shows a low peel strength owing to the intrinsic brittleness of intermetallic. However, a secondary rolling leads to a shear-induced breakage of the sandwich structure, whereupon the peel strength significantly increases from 1.3 N/mm to 12.7 N/mm on account of an effective bonding of the Mg/Al interface. The secondary rolling not only eliminates the influence of MgO on the interface, but also improves the bonding strength of the interface. Furthermore, the clad sheet can obtain an excellent elongation (21%) and remain of high interfacial strength (∼12 N/mm) after the recovery annealing.