▎ 摘　　要

Graphene nanoplatelets (GNPs) are commonly regarded as an ideal reinforcement for metal matrix composites because of their excellent mechanical properties. However, these excellent properties cannot be fully exploited due to GNPs aggregation and poor bonding interface. In the present investigation, GNPs with different residual oxygen amount were prepared by adjusting the amount of KMnO4 oxidant using the modified Hummers method as well as thermal reduction. The GNPs-reinforced ZK60 matrix composites (GNPs/ZK60) were prepared through stir casting. Structure characterization indicates there are C-O, C-O-C and C-C--O oxygen-containing functional groups on the synthesized GNPs, among which all C-C--O and parts of C-O groups are broken and react with Mg to form MgO particles. The formed interfaces in terms of MgO in the GNPs/ZK60 composites are MgO/Mg, having a semi-coherent interface structure, and MgO/GNPs, having an incoherent interface structure. The sandwich interface structure of Mg/MgO/GNPs improves the interface bonding, in which the ultimate tensile strength and elongation of the 0.05 wt.%GNPs-4/ZK60 composite reached 261 MPa and 12.1%, increasing 37.4% and 128.3%, respectively, compared with those of the monolithic matrix. It is suggested the present work might offer a design guideline for graphene reinforced metal matrix composites.