Retarding adiabatic shear failure and optimizing high-speed impact mechanical properties of 7xxx series aluminum alloys via creating layered heterostructures

7xxx series aluminum alloys serve as critical structural materials in aerospace and high-speed transportation systems; however, monolithic hard materials are highly susceptible to adiabatic shear behavior under high-velocity impact loading. Leveraging interfacial constraint, stress redistribution, and deformation coordination, layered heterostructures provide a novel route to retard adiabatic shear failure and optimize dynamic mechanical properties. In this paper, the AB laminate was fabricated from 7A52 (A) and 7A62 (B) aluminum alloys via hot roll bonding. The mechanical properties and failure mechanisms of the laminate under high-speed impact loading were systematically investigated using a Hopkinson pressure bar and quasi-static compression tests. The results reveal that heterogeneous deformation between the soft and hard layers generates a strain gradient near the interface. This strain gradient promotes dislocation accumulation and establishes long-range internal stresses, thereby enhancing the strain hardening capacity of the material. The critical strain for adiabatic shear of the AB laminate (0.157) is higher than that of the 7A62 monolithic sheet (0.128), and the laminate exhibits the longest load-bearing time (48 μs). Meanwhile, the interface-affected zone (IAZ) deflects and disperses adiabatic shear bands (ASBs), the soft 7A52 layer retards ASB initiation, and the 7A01 bonding layer blunts and deflects cracks. The synergy of the three effects retards adiabatic shear failure in the AB laminate. This study establishes a qualitative framework that correlates layer interfaces with strain gradients, providing theoretical insights into the mechanisms by which heterogeneous interfaces regulate the impact resistance and failure behavior of laminates.