Microstructure control of highly oriented short carbon fibres in SiC matrix composites fabricated by direct ink writing

A novel method is proposed for fabricating highly oriented carbon fibre reinforced SiC ceramic composites (C-f/SiC) by direct ink writing (DIW). For the first time, the control of carbon fibers' orientation in DIW was studied by numerical simulation. An interfacial layer was prepared by chemical vapor infiltration (CVI). The microstructure and phase composition of C-f/SiC were studied by scanning electron microscopy and X-ray diffraction, respectively. The results showed that fibers of different interfacial thicknesses could be obtained effectively by varying the CVI time. The breakage of short fibres remarkably improved the fracture toughness of the parts. The specimens showed excellent mechanical properties with bending strength of 274 +/- 13 MPa and fracture toughness of 5.82 +/- 0.25 MPa m(1/2). This method could be extended to the preparation of other resin and ceramic composites.