Effect of Interlayer Materials on the Interfacial Microstructure and Dynamic Mechanical Properties of 7B53 Aluminum Alloy Composite Plates

The choice of aluminum alloys used as the interlayers significantly influences the interfacial bonding properties and dynamic impact mechanical properties of 7B53 aluminum alloy composite plates (7A52/interlayer/7A63). In this study, the influence mechanism of different aluminum alloy interlayer materials (7A01, 6061, 2024 aluminum alloy) on the interfacial metallurgical bonding quality and the dynamic mechanical behavior at high strain rates (1700−3200 s⁻¹) was systematically investigated using tensile-shear tests, Charpy impact tests, split Hopkinson pressure bar (SHPB) tests, and scanning electron microscopy (SEM). The results show that the composite plate with the 6061 interlayer exhibits the optimal interfacial bonding performance, achieving a maximum shear strength of 109.6 MPa, which is 36.5 MPa higher than that of the plate with the 7A01 interlayer (73.1 MPa). This improvement is attributed to the fact that the 6061 alloy promotes the formation of fine and uniform grains at the interface, thereby effectively strengthening the interfacial region. SHPB tests reveal that the inhomogeneous deformation of the interlayer interrupts the penetration of cracks into the 7A52 layer and promotes crack deflection along the interface. The composite plate with the 7A01 interlayer shows low strain rate sensitivity. The plate with the 6061 interlayer, while decreases in flow stress due to thermal softening within the strain rate range of 1700–2700 s⁻¹, maintains stable deformation under high-velocity impact owing to its excellent ductility. Compared to the composite plate with the 2024 interlayer, the plate with the 6061 interlayer achieves higher plastic strain while retaining relatively high yield strength. The 6061 interlayer composite plate successfully achieves an effective integration of the high toughness of 7A52 and the high strength of 7A63, providing an important theoretical basis for the design of impact-resistant protective structures for armored vehicles.