Interfacial adhesion quality in 3D printed continuous CF/PA6 composites at filament/matrix and interlaminar scales

Abstract Fused deposition modelling (FDM) is a promising additive manufacturing technology for the fabrication of continuous fibre reinforced thermoplastic composites. However, a major concern is the performance of the interfacial bonding in these composites. The aim of this study is to evaluate the interface quality of a 3D printed carbon/PA6 composite at two scales: the filament/matrix scale and the interlaminar one. Two different types of samples were made: monofilament composites for performing fragmentation tests, and double cantilever beam (DCB) samples for realising mode I interlaminar fracture tests. After measuring the strength of the individual carbon filament, the fragment lengths were observed by micro-CT and measured in monofilament composites in order to calculate the interfacial shear strength (IFSS). The DCB tests allowed the determination of the interlaminar fracture toughness (GIc) for 0°//0° and +45°//-45° interfaces. The obtained results are promising for such 3D printed composites.