Effect of synergistic surface treatment on the bonding strength and durability performance of aluminum-lithium alloy adhesive joints

The effect of synergetic surface treatments on the adhesion performance and strength durability of aluminum-lithium alloy bonded joints was investigated. The synergistic modes combine the advantages of different surface treatments, rough morphologies were firstly generated and then porous oxide layer structures were produced on the rough surfaces, so more porous structures and suitable rough characteristics were generated on the substrate to enhance the bonding performance of adhesive joint. The surface characteristics, surface wettability, fracture morphology, shear strength and strength durability of samples subjected to different surface treatments were compared and analyzed. The experimental results indicated that the synergistic treatments had a positive effect on the strength performance and environmental durability of bonded joints, with the highest surface free energy of 80.6 mJ/m² and shear strength of 40.2 MPa, and also had the best environmental durability with a strength reduction of 8.2 % during the hot-humid exposure.