Surface microtexturing design, laser-etching and adhesive failure of aluminum alloy single-lap-joint: Experiment and simulation

This study investigates the design and laser etching of surface microtextures on Al substrate to significantly improve the adhesive performance. Microstructures with different patterns were designed and fabricated. Also laser etching parameters such as etching power, line space and number of scans were thoroughly studied. The obtained microstructures exhibit excellent hydrophilicity, which is beneficial for the permeation of adhesives and formation of micromechanical interlocking. When testing the shear strength of the Al single-lap-joint, the results show great improvement compared with unetched specimens. In terms of the significance of laser parameters and textures on shear strength, power is the most significant, followed by number of scans, and finally line space and textures. The specimen designed with X-texture and etched by 20 W with scan space of 0.2 mm and number of 2 scans achieves the highest shear strength of 24 MPa and presents an improvement of 1225% in shear strength. In addition, multi-scale simulations were conducted to effectively demonstrate the interfacial bonding behavior and damage process of Al single-lap-joint. The proposed method shows great potential in improvement of bonding performance.