Study of microstructure and investigation of mechanical properties of pure aluminum-graphene nanocomposite using ball mill method in casting process with mechanical and electromagnetic stirring

In recent scientific studies, the use of graphene has been considered due to its positive effect on the properties of composites, including mechanical, electrical and thermal properties. In this research, the microstructural and mechanical properties of pure aluminum nanocomposite cast reinforced with 0.5 wt% graphene with mechanical-electromagnetic stirrer and then hot extrusion and finally annealing, in two methods of using ball milling and without using ball milling process, was investigated. By applying both mechanical and electromagnetic stirring techniques, combining both shear and body forces can cause more turbulence in the molten metal that lead to as well as distribute reinforcing particles, decreasing the dendritic structures and refining the grains during solidification. The microstructural studies showed that in the ball mill method, the distribution of graphene nanoparticles and reduce grain size in the matrix phase is significantly better than the non-ball mill method. Also, in the method of ball mill, hardness, tensile strength and compressive strength increased by 19.7, 142.8 and 11.7%, respectively, and in the method without mill, 9, 85.2 and 13.5%, respectively, compared to pure aluminum. The elongation decreased by 6.8% in the ball mill method and 35.4% in the non-ball mill method.