Enhancing the adhesive bonding strength of Ti6Al4V sheets with fiber laser texturing

Abstract

In this study, Ti6Al4V sheet blocks with a thickness of 1 mm were joined in a single lap joint form using a two-component epoxy adhesive binder. In order to increase the bonding performance, the surfaces were prepared with sandpaper, acid etching, and laser texturing before the bonding process. Laser texturing was carried out with an average 20 W laser power with 25 kHz laser frequency and variable scanning speeds (1000, 750, 500 mm/s). The generated surfaces were examined with an optical microscope, and surface roughness values were measured. The wettability properties of the surfaces were examined by the sessile drop test method. It was observed that the laser texturing process increases surface wettability significantly. The strength of the adhesive joints was determined using a tensile test setup. Additionally, fracture surfaces were examined under a scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDS) analysis was conducted. According to these results, it was observed that all surface preparation processes increased the adhesive bonding and shear lap joint bond strength. Especially, up to a 4.5 times increase was observed compared to the sample not treated with laser texturing.