Migration of nonequilibrium grain boundaries in metal-graphene composites with ultrafine-grained matrix

We propose a theoretical model describing stress-induced migration of nonequilibrium grain boundaries constrained by the presence of second phase inclusions in metal-graphene composites with the ultrafine-grained matrix. Within the framework of the model, the structure of nonequilibrium boundaries is represented as a combination of dislocation structure of equilibrium boundary and dislocations introduced from outside, trapped by the boundary during deformation. Using the disclination theory approach, a change in the energy of the system associated with such migration under the action of applied shear stress was found. It is theoretically shown that the presence of inclusions leads to the strengthening of the material and the suppression of grain growth.