Effect of solid solution aging treatment on damping and mechanical properties of graphene nanoplatelets reinforced Al-Zn-Cu matrix laminated composites

This study systematically investigates the strengthening mechanisms of the solid solution treatment (490 °C × 1 h) and aging treatment (100–250 °C × 1 h) on the mechanical properties of Al-30Zn-2Cu-0.5GNPs laminated composites. A supersaturated α-Al solid solution enriched with Zn is obtained via solid solution treatment at 490 °C for 1 h. Subsequently, during aging at temperatures between 100–250 °C, the nano-sized η-Zn phase exhibits distinct precipitation kinetics relative to the θ-CuAl 2 phase. Low-temperature aging at 100 °C facilitates uniform precipitation of nano-sized η-Zn particles while suppressing the coarsening of θ-CuAl 2 precipitates, thereby enhancing the compressive strength to 626.2 MPa. Concurrently, the synergistic interaction between nano-precipitates and graphene nanoplatelets (GNPs) preserves interfacial dislocation slip capacity. The damping performance (tan δ = 0.01882) remains comparable to that of the original specimen while retaining high damping capacity. Aging at 250 °C leads to a simultaneous decline in mechanical and damping properties, attributed to the coarsening of precipitates and degradation of interfacial stability. In this study, the size distribution of precipitates and interfacial stability are precisely controlled through optimized heat treatment processes, achieving synergistic enhancement of the overall mechanical-damping properties in laminated composites.