Effect of pure Cu foil interlayer on the microstructure and mechanical behavior of Mg/Al composite sheet

In this study, a Mg/Al composite sheet containing an ultrathin Cu foil interlayer was successfully fabricated by single-pass hot roll bonding. The influence of Cu foil on microstructure, mechanical properties and deformation behavior of Mg/Al composite sheet were investigated. The results show that the Mg/Al-Cu sheet exhibits a good interfacial bonding, and there is no obvious intermetallic compounds (IMCs) formation at the interface. The Cu foil is beneficial to refine the average grain size of the Mg layer and weaken the texture orientation intensity of the Mg and Al layers in the Mg/Al-Cu sheet. The Mg/Al-Cu sheet exhibits similar yield strength and ultimate tensile strength to the Mg/Al sheet, but with a significantly higher elongation of 17.3 %. Furthermore, the interfacial shear strength of Mg/Al-Cu sheet is significantly lower than that of the Mg/Al sheet, primarily due to the extensive formation of CuO on the surface of the Cu foil during the rolling process.