Thermally assisted extrusion-based 3D printing of continuous carbon fiber-reinforced SiC composites

A novel method for the three-dimensional (3D) printing of continuous carbon fiber-reinforced SiC composites is proposed. A thermally assisted extrusion-based 3D printing system was developed to simultaneously print a thermoplastic SiC ink, which exhibited shear-thinning properties at high temperatures and underwent rapid solidification at room temperature, and continuous carbon fiber bundles. The viscosity, thixotropy, and printability of the thermoplastic ink were optimized by varying the content of SiC whiskers. Furthermore, the established correlation between the ink composition, nozzle structure, and printability demonstrated that fiber deviations in filaments could be minimized by selecting an appropriate whisker content and coaxial nozzle. A trade-off between the dimensional accuracy and mechanical properties of the printed materials was achieved by optimizing the ink composition and nozzle structure. Finally, PIP was combined for composite densification; the final specimens exhibited a maximum bending strength of 149.1 ± 8 MPa and fracture toughness of 5.32 ± 0.4 MPa·m^1/2.