Win-win strength and ductility of SnO2@rGO/ZK61 composite with interface in a patch stitching way

SnCl 2 ·2H 2 O was applied as tin source to uniformly deposit SnO 2 nanoparticles (1–5 nm) on rGOs by adjusting the mass ratio of SnCl 2 ·2H 2 O and rGO via a hydrothermal reaction. During the hot-press sintering, the Sn and O atoms of SnO 2 @rGO gradually diffused into Mg matrix and formed Mg 2 Sn and MgO nanocrystals along the interface between rGO and Mg matrix with a semi-coherent relationship. The resulting heterogeneous interface structure acts like “stitches” to sew the rGO “patches” onto the Mg “cloth”, which largely enhanced the interfacial bonding. As reinforcement, SnO 2 @rGO caused significant grain refinement in ZK61 alloy, especially leading to a hierarchical architecture with micro-nano grains ascribed to the heterogeneous sites on rGO. The strength and ductility of SnO 2 @rGO/ZK61 composite (UTS of 375 MPa, YS of 344 MPa, and EL of 20.6%) were simultaneously enhanced than those of ZK61 alloy (UTS of 309 MPa, YS of 276 MPa, and EL of 17.3%), which successfully overcomes the traditional strength-ductility trade-off in Mg alloys. This work provides a novel design strategy for high-performance graphene reinforced Mg matrix composites by interfacial engineering.