Yuqiang Chen, Jiaying Fu, Weijin Cai, Baoqi Jiao, Wenhui Liu, Xingxing Zhang
• T6I4 aging boosts hardness by 15.3 HV and high-strain-rate impact energy by 7.9% • T6I4-treated alloy exhibits superior dynamic strength and thermal stability at 3000 s - 1. • Enhanced corrosion resistance is achieved with higher potential and lower current density. • Refined precipitates and discontinuous GBPs are key to the improved performance. • T6I4 effectively overcomes the strength-corrosion trade-off in 7B52 laminated alloy. The T6I4 interrupted aging treatment was developed for 7B52 laminated aluminum alloy to overcome the strength–corrosion trade-off caused by conventional T6 aging. Compared to T6, T6I4 induces a refined microstructure characterized by discontinuous grain boundary precipitates (GBPs) and narrower precipitate-free zones (PFZs), thereby simultaneously enhancing mechanical and corrosion performance. Experimental results show that T6I4 increases hardness by 15.3 HV and peak stress by 21.5 MPa, and improves energy absorption by 7.9% at a strain rate of 3000 s −1 using the Split Hopkinson Pressure Bar (SHPB). It also yields a higher corrosion potential, lower current density, reduced surface degradation, and narrower interfacial cracks in salt spray tests. These improvements arise from the optimized precipitation behavior during dual-stage aging, which simultaneously strengthens the matrix and suppresses continuous grain boundary attack. The optimized T6I4 process thus provides a viable route to enhance the service performance of 7B52 alloy in demanding environments.