Mechanical and Tribological Properties of Graphene-Reinforced Bimodal AA7075 Composites

The current research work presents the synthesis and characterization of graphene-reinforced bimodal (Bi) AA7075 matrix composite by powder metallurgy route. The bimodal AA7075 alloy is optimized with micro (mu)- and nano (n)-crystalline grain morphologies in order to achieve better strength while retaining the vital minimal ductility. The effect of milling duration on grain size and particle uniformity is characterized by XRD and TEM. Density, hardness, compressive strength, and wear rate of bimodal composites are investigated. The addition of optimized 20% mu AA7075 particles to nAA7075 particles provides the minimum necessary ductility in bimodal composites while increasing the interplanar space between the phase lattices. The use of graphene up to 0.75% enhanced wear resistance in comparison with the other compositions. The existence of both adhesive mechanisms and abrasive wear further reveals the plasticity of the bimodal composites, which are ideally suitable for engineering applications requiring greater strength and reliability.