Graphene Network with Ni and Al Nanoparticles as the Composite Precursor: Atomistic Simulation

In this work, the method of fabrication of the composites based on a graphene network and metal nanoparticles (Ni and Al) by deformation-heat treatment is considered by molecular dynamics simulation. A graphene network filled with Al or Ni nanoparticles are considered to study the fabrication of the composites and their mechanical properties. The diameter of Ni and Al nanoparticle is 6.2 and 7.5 Å, while in the final composite state, the ratio of metal and carbon atoms in the graphene/Al and graphene/Ni systems are 8 and 7.7 at.%, respectively. It is shown that hydrostatic compression is an effective way to obtain graphene/metal composites. In the compressed structure (composite state) no pores are found since compression is conducted to the maximum possible density. It is found that the graphene/Ni composite has better mechanical properties in comparison with the graphene/Al composite. The enhanced mechanical properties of the graphene/Ni composite are explained by the formation of a graphene network of high strength with metal nanoparticles uniformly distributed over the graphene pores. It has been established, that in the graphene/Al composite, both during hydrostatic and uniaxial tension, due to its low cohesion energy with graphene, metal nanoparticles begin to coagulate, which is more energetically favorable. The larger Al nanoparticles that appear in the structure are the weak places of the composite, where the fracture of the composite occurs most easily.