Journal of Adhesion Science and Technology, cilt.37, sa.22, ss.3277-3295, 2023 (SCI-Expanded)
In this paper, the effect of the laser-ablated pattern designs on the bonding performance of single-lap dissimilar joints between Polyamide 6 (PA6) composite reinforced with 15% short glass fibers (PA6-15GF) and 7075 aluminium (Al) alloy in O-temper condition, manufactured through hot-pressing technique, is studied by tensile-shear testing. From the optical microscopy (OM) and scanning electron microscopy (SEM) observations, it is found that laser ablation can create a favorable surface morphology for the adhesiveless joints. This is proved by obtaining a significant improvement in the lap-shear strength of the treated samples which can be up to 36%. According to the X-ray photoelectron spectroscopy (XPS) results, the surface chemistry is altered by generating an active oxide layer which is a more suitable condition for the PA6-Al direct bonding. Moreover, achieving favourable surface characteristics is shown by the static contact angle (SCA) findings with the acquired increase in surface wettability after the laser ablation. It is observed that the SCA can be decreased from 83 ± 2 (for as-received Al) by approximately more than 65%. The results gained from the experiments demonstrate that the shape of the laser-induced surface pretreatment markedly affects the strength of metal/composite single-lap joints (SLJs).