A micromechanical model of graphene-reinforced metal matrix nanocomposites with consideration of graphene orientations

In this paper, a new micromechanical model is developed for graphene-reinforced metal matrix nanocomposites (MMNCs) to effectively describe the mechanical properties of the new attractive engineering materials with high specific strength. The key influence of the misorientation of randomly-distributed graphene nanoplatelets (GNPs) is especially considered. The strain rate and temperature effects are also introduced through the dislocation-mechanics-based metal matrix model. Then the new model is applied to the nanocomposites of GNP/Al2024, GNP/Al and GNP/Cu, respectively. The comparison of model predictions and experimental data suggests that the model can represent the elastoplastic deformation behaviors of the graphene-reinforced MMNCs well. The strengthening effect by graphene in the nanocomposites is approximately linear to its volume fraction within a small range and also to the aspect ratio of graphene platelets when their average length is less than a critical value. Moreover, the dynamic thermomechanical behavior of the GNP/Al2024 nanocomposite is predicted for the first time. The temperature-softening effect becomes weaker under dynamic loading conditions while the rate sensitivity would be enhanced at elevated temperatures.