Abstract
A brief review of the theoretical models which describe mechanisms of the plastic deformation and fracture toughness enhancement in bimodal metal-graphene composites with nanotwinned structure is presented. In the framework of the models, the plastic deformation in such composites occurs due to the lattice dislocation slip and the grain boundary sliding in nanocrystalline/ultrafine-grained matrix, and the lattice dislocation slip and the migration of the twin boundaries in large grains with nanotwinned structure. Within the review, the migration of nanotwin boundaries in the large grains releases in part local stresses near crack tips and provides the fracture toughness enhancement in bimodal metal-graphene composites with nanotwinned structure. At the same time, the presence of the graphene inclusions in metal-matrix induces the crack bridging effect which also increases the fracture toughness of bimodal metal-graphene composites.