Synergistic enhancement of mechanical properties and absorption-dominated EMI shielding in laminated 3D-Graphene/AZ31B composites

• Laminated 3D-Gr/AZ31B composites achieve simultaneous enhancement of strength and EMI shielding. • The composites overcome the strength-ductility trade-off with superior strength (∼295 MPa) and elongation (∼28.76%). • An absorption-dominated shielding mechanism is established via phase cancellation in the porous 3D network. • 3D-Gr promotes grain refinement and alters texture evolution, effectively activating non-basal slip systems. This study tackled the challenge of concurrently improving the mechanical strength and electromagnetic interference (EMI) shielding efficacy of magnesium alloys. Laminated composites integrating AZ31B magnesium alloy with a three-dimensional graphene (3D-Gr) network were fabricated and processed via hot-pressing at different temperatures. The 3D-Gr/AZ31B composite hot-pressed at 300°C demonstrated superior mechanical properties and the highest electromagnetic interference shielding efficiency (EMI SE) compared to pure AZ31B. The strength enhancement resulted mainly from grain refinement and effective load transfer. The 3D-Gr layer significantly augmented EMI SE by extending the transmission paths of electromagnetic waves within the material. Its unique structure, combined with inherent porosity, promoted multiple reflections leading to phase interference-induced cancellation, thereby boosting absorption-dominated shielding. This work provides a successful approach for designing lightweight structural materials with inherently high EMI shielding performance.