Effect of the lateral area of graphene nanosheets on the strengthening mechanism in FGH96 superalloy composites

To improve the strengthening effect of graphene reinforcement in nickel-based superalloys, introducing graphene nanosheets (GNSs) with multiple lateral areas into the GNS/metal system is a promised strategy to take full advantage of the superior properties of graphene reinforcement. In this work, the impact of the GNS lateral area on the strengthening effect of FGH96 nickel-based superalloy composites (DLA-GNS/FGH96) was investigated for the first time. Microstructural and tensile tests revealed the uniform distribution of the GNSs in the DLA-GNS/FGH96 metal matrix with lateral areas ranging from 0.06 ± 0.02 to 225.2 ± 20.3 μm². The GNSs exhibited a well-balanced mechanical property on the elongation and yield strength of the DLA-GNS/FGH96 composites. Investigation of the fracture morphology and mechanism indicated that there existed a transition of the strengthening mechanism (between the strengthening mechanism of Orowan and the strengthening mechanism of load-transfer) for the GNSs, which was closely associated with the lateral area of the GNSs. This finding put forward new ideas to better comprehend the strengthening mechanisms of GNS-reinforced metal-matrix composites.