Effect of Surface Texture on the Adhesion Performance of Laser Treated Ti6Al4V Alloy

The growing demand in lighter and safer structures generates the requirement of lighter joining strategies, particularly for lightweight metal alloys, composites, and also joining dissimilar materials together. Titanium alloys stand out as the conventional choice for materials for light weight structures. Adhesive bonding of titanium is an appealing route for joint design, also for the possibility of joining it with dissimilar materials. The realization of a strong joint depends not only on the joint design and type of adhesive, but also on the preparation of the adhering surface. Laser texturing presents advantages compared to common surface preparation processes in terms of eco-compatibility, energetic efficiency, ease of manufacturing, and repeatability. This work presents a preliminary investigation on laser texturing of Ti6Al4 V alloy with a pulsed fiber laser source with the aim to increase surface adhesion for bonding. Particularly, different surface textures are proposed, and laser machining strategies are developed. The results showed that laser texturing provided up to eightfold and 30% higher shear strength compared to plain and sand blasted surfaces, respectively. Failure analysis showed that a margin of improvement is still possible by adapting the surface texture for better cavity filling and reducing surface damage caused by the laser treatment.