Adhesive bonding of additively manufactured parts enables highly efficient lightweight designs. To achieve high adhesive bond performance, it is essential to consider the surface properties of the adherends. Previous studies have shown that the inherent roughness of Ti6Al4V parts fabricated by laser powder bed fusion (PBF-LB) can contribute to high bond strength under quasi-static loading. In the present work, the influences of surface morphology on adhesive bond performance were examined under static and fatigue loading conditions. Moreover, the environmental durability of the bonded joints was assessed for a hot-wet condition. In the as-built state (i.e., degreased PBF-LB-surface) the build orientations 0°, 45° (Up-/Downskin) and 90° were investigated, resulting in four different surface morphologies. Furthermore, grit blasting and laser treatment were used to modify the surface properties and examine their effect on the adhesive bond performance. Characterizing the surfaces was done by scanning electron microscopy and confocal laser scanning microscopy. The quasi-static bond strengths and fatigue lifetimes were examined through metal-metal single step-lap joint testing. The number of attached particles on the PBF-LB manufactured surfaces was found to correlate with the tensile shear strength and fatigue lifetime of the adhesive bond. Under fatigue loading, the particle-induced interlocking effect was mainly effective in the low-cycle-fatigue regime. A significantly enhanced bond performance was achieved by laser treatment, which created a hierarchical surface morphology, consisting of the inherent microscopic surface features of PBF-LB-Ti6Al4V and a laser-induced nanoporous oxide layer. This hierarchical surface structure increased the bond strengths by up to 162% and extended the fatigue lifetimes by at least 130% in comparison to the as-built surface condition. However, further improvements are necessary to enhance the environmental durability of the oxide layer.    «

Adhesive bonding of additively manufactured parts enables highly efficient lightweight designs. To achieve high adhesive bond performance, it is essential to consider the surface properties of the adherends. Previous studies have shown that the inherent roughness of Ti6Al4V parts fabricated by laser powder bed fusion (PBF-LB) can contribute to high bond strength under quasi-static loading. In the present work, the influences of surface morphology on adhesive bond performance were examined under...    »