Enhanced interfacial bonding and microstructure evolution in Mg/Al composite plates with Al Core and Zn interlayer via extrusion-shear

To address the issue of brittle intermetallic compounds (IMCs) readily forming at the interface of lightweight magnesium/aluminum composites, which hinders their application in automotive and aerospace sectors, this study investigated the modification effect of adding a 0.1–0.3 mm Zn interlayer to aluminum-core/magnesium-shell magnesium/aluminum composites. Results indicate that the Zn interlayer reduces the thickness of brittle Mg-Al intermetallic compounds (IMCs) at the interface by 60% through the formation of ductile Mg-Zn phases (e.g., MgZn transition layers). Simultaneously, it increases the interfacial shear strength from 20.8 MPa in the control sample to 38.8 MPa (an 87% increase). Its diffusion barrier function effectively inhibits direct Mg-Al interaction. This study confirms that adding a Zn interlayer is an effective strategy to improve interface compatibility and enhance the performance of aluminum-core/magnesium-shell composites, providing key technical support for the practical application of such materials.