High-performance carbon fiber reinforced polyether-ether-ketone composite pellets 3D-Printed via screw-extrusion additive manufacturing

The lightweight and high-strength carbon-fiber reinforced polyether-ether-ketone composites (PEEK-CF) are highly favorable for a plethora of strength-demanding and weight-sensitive applications. Yet, the traditional filament-based three-dimensional (3D) printing approaches are limited both in throughput and reinforcement content, leaving a wide gap between the service requirement and attainable strength. In this study, pelletized PEEK-CF composites with high CF content (up to 30 wt%), are successfully printed with a custom-designed screw-extrusion 3D-printer. Microstructural characterization reveals the CFs, averaging around 226 μm long, are generally well aligned along the printing direction. The printed PEEK-CF composites exhibit an outstanding tensile strength, reaching over 190 MPa. Post-print treatment, such as hot compression, can further enhance the strength over 200 MPa. Additionally, those printed specimens also exhibit superior thermal stability, the tensile strength of which still reaches64 MPa at 250 °C. Overall, the tensile strength of the composites agrees well with the Kelly-Tyson equation. The results of this study may incentivize new strategies for designing and optimizing the performance of 3D-printed PEEK-CF composites.