Tensile strength and nanohardness of Cu with graphene / Cu composite coating: atomistic simulation

The rapid development of technology, industry, and aerospace requires the search for new materials with high strength, light weight, and enhanced corrosion resistance. Graphene-based composites have unique mechanical properties and can be used as protective and reinforcing coatings to increase the strength of metal surfaces. This paper investigates the strength and hardness of Cu surface with a graphene / Cu composite nanocoating using the classical molecular dynamics simulation by LAMMPS software package. The deformation mechanisms during uniaxial stretching and indentation of coated copper are also considered. It has been found that a 2.4 nm thick composite coating increases the tensile strength of the Cu surface by more than two times. The hardening of Cu with a composite coating under uniaxial tension was associated with strong carbon bonds in the graphene network of the composite coating and with dislocation hardening at the interface between Cu and the coating. The failure of Cu with a composite coating under uniaxial tension begins with the coating failure. The hardness of the coated Cu surface increased by 6 %. Such a small increase in hardness was associated with a relatively low hardness of the composite. As a result, the graphene / Cu composite coating was found to be a promising strengthening and protective material for metal surfaces.