Additive Manufacturing of SiC Ceramic Composite Reinforced With Continuous/Short SiC Fiber by Extrusion Printing and LSI

ABSTRACT

Extrusion‐based additive manufacturing combined with liquid silica infiltration was employed to fabricate continuous‐ and short‐SiC‐fiber‐reinforced SiC ceramic composites with complex geometries and high density. The rheological behavior of the SiC printing slurry was systematically optimized by adjusting the solid loading and the contents of dispersant and binder. Graphitic carbon microspheres were introduced as a carbon source for silica infiltration, and their effects, together with those of short SiC fibers, on slurry rheology and composite properties were investigated. A coaxial nozzle was adopted to enable the simultaneous incorporation of continuous and short SiC fibers during the printing process. The results show that a slurry containing 76 wt.% solid loading, 0.8 wt.% polyethylene glycol, and 0.2 wt.% sodium alginate exhibited excellent flowability, shape retention, and structural stability. Increasing the content of graphitic carbon microspheres further improved the thixotropic recovery and structural build‐up of the slurry, whereas the addition of short fibers adversely affected its rheological performance. Owing to the synergistic reinforcement of continuous and short fibers, the flexural strength and fracture toughness of the SiC ceramics increased from 273.2 MPa and 4.3 MPa·m ^1/2 for the fiber‐free material to 295.5 MPa and 5.1 MPa·m ^1/2 , respectively, without a significant change in bulk density. In addition, the introduction of continuous and short SiC fibers enhanced the high‐temperature oxidation resistance of the composites. These results demonstrate the feasibility of extrusion‐based additive manufacturing combined with silica infiltration for producing high‐performance SiC ceramic composites with tailored architectures.