Fabrication of high-strength porous SiC-based composites with unidirectional channels

Carbon fiber reinforced SiC-based composites with unidirectional channels were obtained by freeze-casting and chemical vapor infiltration techniques, and their microstructure and fracture behavior were investigated. The results indicated that the sizes of the unidirectional channels could be controlled in the 15-70 μm range. The significant pseudo plastic and ductility features of the porous SiC-based composite were demonstrated during the fracture process. The strains of the composites reached 4 ± 1% and 50 ± 6% during bending and compressive experiments, respectively. The bending and compressive strengths, 123 ± 20 and 99 ± 15 MPa, respectively, were far superior to those of homogeneous ceramics presenting the same porosity. Combining the aforesaid method with 3D printing techniques, a SiC-based composite part with controlled macro-micro channels was fabricated, which indicated that this method could be useful for fabricating ceramic parts with complex structure and superior mechanical performance.