Regulation of solution treatment to improve the interfacial bonding quality and mechanical properties of 7B52 laminated aluminum alloy

Insufficient bonding quality between layers severely restricted the application of 7B52 laminated aluminum alloy in armor protection, and the contribution of the solution treatment on interfacial bonding quality is often ignored. In this work, the interfacial bonding quality, mechanical properties, and damage mechanism during the deformation of 7B52 laminated aluminum alloy treated at different solution temperatures (450 °C, 460 °C, 470 °C, 480 °C) were investigated. When the solution temperature is below 480 °C, the interfacial hardness increases gradually with the rising solution temperature, which is attributed to the enhanced hardness of the matrix and improved interfacial bonding quality. However, when the temperature reaches 480 °C, the matrix hardness experiences a slight decrease, and the improvement in bonding quality becomes the main reason for the improvement of interfacial hardness. Additionally, increasing the solution temperature facilitates the growth of interface recrystallized grains, leading to interfacial grain boundary migration (IGBM) and enhancing element diffusion at the bonding interface. These factors are beneficial for improving the interfacial bonding quality of 7B52 laminated aluminum alloy. Moreover, uneven deformation and cracking are prone to occur at the 7A62/pure Al interface, and the increase of solution temperature effectively increases the maximum shear strain that the interface can tolerate, which reaches 13.5 % at 480 °C. Besides, the optimal comprehensive mechanical properties are achieved at a solution temperature of 470 °C, with a yield strength of 520.9 MPa, tensile strength of 567.8 MPa, and interfacial bonding strength of 89.2 MPa.