- Formation of Cu–C composite is a difficult technological problem: carbon is practically insoluble in copper. We show that the heat treatment of the Cu–C composite leads to the formation of a thin (approximately 50 nm) interface which provides the bonding between fiber and matrix. The HR SEM study displays the formation of small copper nano-crystals in the interaction zone. This structure of the interface is predicted by molecular dynamic and Monte Carlo simulations with semi-empirical repulsive Cu–C interatomic potentials. We show that inclusion of a small amount of carbon in fcc copper leads to strong deformation of the copper host matrix in the vicinity of carbon. Decrease of stresses in the lattice may be reached by the formation of the developed surface in nano-crystalline structure.