Using flexible hydrothermal carbon-coated continuous carbon fiber to fabricate Cf/ZrB2-SiC composites by fused deposition modeling and precursor infiltration pyrolysis

In additive manufacturing of continuous fiber reinforced ceramic composites, the carbon fiber is difficult to give full play to its toughening effect without interface, and the high-viscosity resin, ceramic precursors or slurry is hardly to fully infiltrate into fiber bundles, which are not conducive to obtain high-performance ceramic com-posites. In this work, sugar-derived carbon acts as interface was deposited on continuous carbon fiber by hy-drothermal reaction. Flexible hydrothermal carbon-coated continuous carbon fiber is appropriate for 3D printing. Continuous carbon fiber/ZrB2-polycaprolactone(PCL) filaments used for fused deposition modeling (FDM) was prepared by pre-impregnation-coating process. Ultrasound significantly improves the impregnation effect of ceramic slurry into fiber bundles. Cf/ZrB2-PCL billets with different fiber orientations were fabricated by FDM of continuous Cf/ZrB2-PCL filaments. The Cf/ZrB2-PCL billets were further densified by infiltration and pyrolysis of SiC precursor. The flexural strength and fracture toughness of Cf/ZrB2-SiC composites could reach 218.1 +/- 21.3 MPa and 9.40 +/- 1.45 MPa m1/2, respectively.