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Structural and functional integration of metal matrix composites is both a goal pursued by researchers and a challenging issue. In this study, a series of Al3Fe@Fe core-shell structured micro-sized particle reinforced magnesium matrix composites were prepared by using AZ31 alloy and Fe powders. The Al3Fe@Fe core-shell structure induces the “back-stress” strengthening in the composite due to the difference in deformation ability of matrix, Al3Fe “shell” and Fe “core” during the deformation process. This also improves the strain hardening ability of the composite, resulting in synchronous improvement of both strength and ductility. In addition, the reinforcing particles with “core-shell” structure endow the composite with certain magnetism, achieving a synergistic contribution of dielectric and magnetic losses, significantly enhancing the electromagnetic shielding effectiveness of the composite. Compared with the matrix alloy, the addition of 15 wt% Fe in the composite increased the SET by 70 %, and the SEA/SET increased from 0.46 to 0.73.

More requirements of electromagnetic interference (EMI) shielding performance are put forward for lightweight structural materials due to the development of aerospace and 5G communications. Herein, graphene oxide (GO) decorated with SnO2 coating is introduced as reinforcement into AZ31 Mg alloy. During the smelting process, the MgO layer is in situ gernerated at interface between GO and the molten Mg alloy matrix by consuming SnO2. In the solid state, such kind of interface structure can improve the GO-Mg interface bonding intensity, also significantly generate stacking faults. The AZ31 composite reinfoced by trace modified GO (0.1 wt%) exhibits high ultimate strength and almost the same elongation with AZ31 alloy. Compared with AZ31 alloy, the yield strength and ultimate tensile strength of composite are increased by 33.5% and 23.7%, respectively. Meanwhile, the multi-level electromagnetic reflection from the multi-layer structure of GO and the interface polarization caused by the MgO mid-layer can significantly improve EMI shielding performance. The appropriate interface design strategy achieves the effect of “two birds with one stone”.