Metal/Graphene Composites Obtained from Graphene Network: Tensile Strength

Metal/graphene composites with a metal matrix and graphene reinforcement are very promising innovative materials due to their improved mechanical and physical properties. In this paper, the possibility of fabricating a composite from a graphene network filled with nickel (Ni), copper (Cu) and aluminum (Al) nanoparticles is shown by molecular dynamics simulation. Composites are obtained by hydrostatic compression at 0.7 of the melting temperature of the metal nanoparticles. It is found that the Ni/graphene composite exhibits the highest ultimate tensile strength (89.5 GPa) and Young’s modulus (296.9 GPa) compared to 35.1 and 65.9 GPa for Cu/graphene and 36.8 and 109.1 GPa for Al/graphene, respectively. The Ni nanoparticles were uniformly distributed throughout the graphene network, providing high strength. Indentation simulations confirm this trend: the Ni/graphene composite exhibits a hardness 1.7 times higher than that of pure crumpled graphene, while Al/graphene shows a value 2.2 times lower, which directly correlates with the tensile strength. The Cu/graphene composite has the best ductility (fracture strain of 0.75 versus 0.45 for Ni/graphene and 0.47 for Al/graphene) due to the easier sliding between the Cu nanoparticles and the graphene during tensile loading. The Al/graphene composite has low strength and ductility because the Al nanoparticles tend to coagulate inside the graphene network and hardly interact with the graphene. For Cu/graphene and Al/graphene composites, fracture occurs at the metal/graphene interface. The results show that it is possible to fabricate metal/graphene composites that are much stronger than pure metal by deformation-temperature treatment. In addition, the mechanical properties can be modified by varying the type of metal.