Effect of Laser Burning Degree on the Strength and Durability of Aluminum Alloy Bonded Joints

Abstract

In this study, the changes in surface microstructure size characteristics under laser processing and the effect of these changes on the strength and durability of adhesive joints were investigated. Different combinations of laser power and scanning times were used to construct the microstructure of the sample surface. The variation laws of depth, width, treated area and blank gap width of the micro-groove structures were studied, and the surface characteristics, wetting properties, bonding strength, failure modes, and strength durability of the sample were compared and analyzed. The results showed that the size of the micro-groove structure on the sample surface increased with the increase of laser power and scanning times, with the maximum change in groove depth being 164%. The influence of laser power on the construction of the microstructure was more significant compared to scanning times. The S-8 sample treated by a laser power of 16 W for 3 times showed the highest strength of 19.69 MPa, and the strength degradation after hygrothermal exposure was only 3.6%. The increase in the microstructure size of the sample surface was beneficial for the penetration and adhesion of adhesive, forming effective mechanical interlocking and stable adhesion interface, thus promoting the improvement of the strength performance and durability of the bonded joint.

Keywords: laser processing, Microstructure size, Bonded joint, Strength durability