Abstract:To investigate the effect of different surface treatments on the bonding strength of Al-Li alloy, the sandpaper grinding, copper chloride etching, sandblasting and phosphoric acid anodizing methods were applied, and the microstructure, roughness, wettability and strength of adhesive joints of different modified surfaces were compared and analyzed. The results show that the surface wettability and bonding properties of Al-Li alloy are improved after surface treatments. Compared to untreated samples, the surface free energy of samples treated with sandpaper, copper chloride etching, sandblasting, and PAA increase by 26.7%, 48.8%, 52.9%, and 71.1%, respectively, and the corresponding adhesive joint strength increase by 152.7%, 204.1%, 285.1%, and 413.5%, respectively. The porous oxide film structure constructed by PAA is more conducive to the penetration and adhesion of adhesive on the sample surface. The surface wettability and bonding strength are significantly improved, with a maximum bonding strength of 38 MPa.