Surface topology modification using 3D printing techniques to enhance the interfacial bonding strength between polymer substrates and prepreg carbon fibre-reinforced polymers

Carbon fibre-reinforced polymers (CFRPs) are increasingly utilised in combination with plastics and metals to manufacture hybrid components. Although hybrid components provide a combination of the advantages of the constituent materials, there are some challenges for the manufacture of high-quality hybrid components, including potentially weak interfacial bonding between the constituent materials. This paper presents a study focused on enhancing the interfacial strength of hybrid components by using additive manufacturing (AM) to manipulate the surface topology of a substrate component. Specifically, the study involved conducting experiments on a polyamide/CFRP hybrid component in which the PA12 substrates were manufactured with a controlled surface topology using polymer powder bed fusion. The mechanical testing study revealed several key findings, including an increase in bonding strength by modifying the substrate surface features, and significant improvements in out-of-plane interlaminar bonding strength by adding substrate surface features such as pins or fluorite lattices. It is shown that normal strength was enhanced by up to 53% between the substrate and pure epoxy, and by 126% between the substrate and a CFRP laminate. These results highlight the potential benefits of using AM technologies to enhance the interfacial strength of hybrid components and suggest directions for future research in this area.