Achieving high mechanical properties and corrosion resistance of Al-Zn-Mg matrix composites via regulating intragranular reinforcements

Al matrix composites generally possess high strength but sacrifice ductility and corrosion resistance resulting from the dense intergranular reinforcements. Herein, we report a solid-state reactive sintering pathway to construct an Al-Zn-Mg composite reinforced by intragranular Cu nanoparticles modified graphene nanosheets (Cu@GNS), which demonstrates both superior mechanical properties (∼630 MPa of tensile stress and ∼9.1% of fracture elongation) and exceptional corrosion resistance. It is shown that the “GNS-Cu/CuAl2-Al” interfacial structure greatly contributes to the load transfer, either by enhancing the GNS-Al adhesion or by elevating the interfacial slippage resistance in terms of the “drag effect” of hybrid particles. Meanwhile, the comprehensive characterization demonstrates that such intragranular Cu@GNS not only enhances the dislocation multiplication efficiency for work hardening but also contributes to the high corrosion resistance via decreasing the corrosion kinetics and suppressing the severely localized corrosion. This work provides a novel strategy for the exceptional mechanical-corrosion combination of composites by tailoring intragranular reinforcements.