Tensile behavior of aluminum alloy (AA7050) metal matrix composite reinforced with graphene fabricated by stir and squeeze cast processes

Metal matrix composites based on aluminum alloy AA7050 reinforced with graphene nanoparticles are fabricated using stir casting and squeeze casting techniques. Mechanical characteristics studies were performed on both the stir cast and squeeze cast composite specimen. Taguchi's L27 orthogonal array was used for the design of experiments. Certain parameters like melting temperature (775, 800 and 825 °C), stirring speed (300, 400 and 500 rpm) and graphene content (0.3, 0.5 and 0.7 wt%) with three levels were considered for the experiments. Based on the experimental results, analysis of variance (ANOVA) was conducted to determine the level of influence of the parameters on the tensile strength of the specimens. The microstructural result shows that graphene particles are uniformly distributed in the aluminum matrix only in the composites with 0.3 wt % graphene irrespective of the process followed for the fabrication of composite samples. It is being found that the tensile properties of both stir cast and squeeze cast samples have been enhanced for 0.3 wt% of graphene in the AA7050 composites. Increasing the graphene content beyond 0.3 wt% results in cluster formation.