Investigation of secondary aging and curing synergy in glass fiber–reinforced rare earth aluminum alloy laminates toward property enhancement

Aiming to address the challenge of reduced strength and impact toughness in traditional fiber-metal laminates after thinning and weight reduction, a process combining aging treatment with thermosetting was developed for glass fiber-reinforced rare earth aluminum alloy laminates. High-strength rare earth aluminum alloy plates were first obtained through solution and aging heat treatment. Subsequently, a synchronous process of secondary aging and thermal curing was applied, resulting in the formation of laminates with enhanced strength and toughness. High-speed impact and tensile fatigue characteristics of the laminates were studied to comprehensively evaluate the property performance. The results indicate that the continuous heat treatment process enhances the strength and ductility of rare earth aluminum alloy laminates, exhibiting significant anisotropy and a fine-grained microstructure, with the ultimate tensile strength reached 618 MPa. Secondary aging strengthening during laminate curing enhanced the toughness and ductility of the aluminum alloy layer, enabling the laminate to fully leverage its energy absorption advantage under high-speed impacts at small angles (30°). At impact velocity of 200 m/s, the absorbed energy value reached 253.66 % of that achieved by the conventional process. Under tensile fatigue load of 139 MPa, the specimen exhibited excellent fatigue resistance with no failure observed after 5 million cycles. The primary failure mode under high stress loads was delamination, indicating that the bridging effect between thin-layer fibers and the aluminum alloy still has certain limitations. These findings highlight the potential of the developed laminates for application in critical impact-resistant structures, thus supporting broader adoption in advanced engineering applications.