Effect of Cu alloying on the damping and compression properties of graphene nanoplatelets reinforced Al-30Zn-xCu alloy matrix composites

For a long time, metal matrix composites (MMCs) have always faced a trade-off between damping and mechanical properties, and this is especially true for high-Zn Al alloy matrix composites. In this study, graphene nanoplatelets (GNPs) reinforced Al-30Zn-xCu-0.5GNPs laminated composites with excellent dampingmechanical property balance were fabricated by flake powder metallurgy and Cu alloying. The addition of Cu element greatly refines the intragranular and intergranular precipitated eta-Zn phases, which not only increases the Al-Zn interfacial area but also weakens the tendency of cracking at the grain boundaries. The increased Al-Zn interfacial area is conducive to the improvement of the damping performance of the composites through the interfacial damping mechanism, but the excessive generation of theta-CuAl2 induced by too high Cu additions will harden the matrix, resulting in a simultaneous decrease in the damping performance and plasticity.