Microstructure design and mechanical properties of grain-gradient graphene/aluminum composites

The metal matrix with mixed grain-gradient structure and the graphene with different charac-teristics could be designed and prepared to ameliorate the plasticity and toughness reduction of the metal matrix composites (MMCs) caused by graphene reinforcement. However, the rela-tionship between the microstructure and the mechanical properties of composites needs to be investigated. In this paper, a self-developed structural modeling program is employed to design and establish a single-edge notch tensile finite element model of the graphene reinforced grain -gradient aluminum (Al) matrix composites, where the distribution and morphology of gra-phene and grains can be redistributed. Then, the grain size dependence of yield strength is introduced into the developed crystal plasticity finite element method (CPFEM) according to the classical Hall-Petch relationship, the damage mechanism of the graphene/Al composites with various designed novel microstructures is analyzed in combination with the cohesive zone model (CZM), and the microstructure of the graphene/Al composites with optimal mechanical properties is obtained. In addition, it is found that the failure mode, strength and toughness of the com-posites could be ameliorated by adjusting the bonding state of graphene-Al interface. This study provides a new insight into the microstructure design and fabrication of the graphene/Al com-posites with optimal comprehensive properties.