Effect of combined surface treatment on the adhesion performance of aluminium-lithium alloy

Abstract

Herein we investigated the effect of various surface treatments, especially the combined surface treatment of grit-blasting and phosphoric acid anodization (PAA), on the surface characteristics and the adhesion performance of aluminium-lithium alloy sheets. For the combined surface treatment, rough surfaces were firstly created by grit-blasting to increase the surface area available for anodization. Next, porous structures were produced on the grit-blasted surfaces by PAA. The surface characteristics, surface wettability, fracture morphology, and shear strengths of samples subjected to different surface treatments were compared and analyzed. The effect of surface roughness on the bonding strength of aluminium-lithium alloys subjected to combined treatments was also investigated. The experimental results showed that combined treatment provided the best wettability and single-lap joint performances, with the highest surface free energy of 81.4 mJ/m2 and shear strength of 40.8 MPa.