Abstract: In fields such as aerospace and automotive manufacturing, adhesive bonding technology is widely used for connecting lightweight metals like aluminum alloys due to its technical advantages, including light structure and simple manufacturing. This paper uses an electrochemical method to texture the surface of aluminum alloy to achieve better adhesive bonding performance. The corrosion characteristics of aluminum alloys in different solutions are systematically studied, and the effects of different current parameters on the microstructure of the aluminum alloy surface and its adhesive bonding performance are further analyzed. The results show that in NaNO₃ solution, a loose corrosion layer easily forms on the aluminum alloy surface, which significantly reduces its adhesive bonding strength. In NaCl solution, chloride ions accelerate the removal of the initial oxide film on the aluminum alloy surface, forming a more compact new oxide layer. Particularly under a current of 5 A, the surface roughness reaches its highest value, and the maximum tensile load of the adhesive joint increases by more than twice compared to the untreated surface. Additionally, the discrete element method was used to simulate the crack initiation and propagation during the tensile process of the adhesive joint under the 5 A condition, revealing the fracture mechanism of the adhesive joint transitioning from interface failure to mixed-mode failure. Finally, based on the experimental and simulation results, a fracture mechanism model for the adhesive joint of aluminum alloy surface electrochemical texturing treatment is established. This research provides an effective new method for achieving efficient pre-treatment of aluminum alloy surfaces and high-performance adhesive bonding.

Key words: aluminum alloy, corrosion characteristics, electrochemical texturing treatment, adhesive bonding, failure model