LASER surface texturing (LST) is a promising technique for enhancing adhesive structural bonding performance by modifying the surface properties of the material to be bonded. This study aims to understand how LASER-induced changes in microstructure, surface chemistry, and topography can contribute to improving the structural bonding of Ti-6Al-4V and Al1050 alloys.

Microstructure refinement, phase transformations, lath formation, and residual stresses induced by LASER treatment will be analyzed by electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). Changes in composition, oxidation states, and element distribution at the surface and subsurface will be revealed using X-ray photoelectron spectroscopy (XPS) and glow discharge optical emission spectroscopy (GDOES). In addition, LASER-induced topographical changes will be described using roughness measurements and X-ray micro-computed tomography (µCT).

Correlations between LASER-induced microstructural changes and mechanical properties will be established, in particular via local micro-hardness tests and via macroscopic tests on bonded assemblies (single lap shear and DCB). Comparisons between untreated, LASER-treated, and sandblasted metal substrates will provide a detailed understanding of the effects of LASER treatment on metal surfaces, thereby contributing to surface optimization.

This research is conducted as part of a Ph.D. funded by IRT Saint Exupéry, within a consortium of aeronautics and space industry companies. The ultimate goal is to develop lighter structures in compliance with REACH regulations while promoting a cleaner alternative to wet chemical surface treatments.