High performance C_sf/SiC ceramic matrix composites fabricated by material extrusion 3D printing and precursor infiltration and pyrolysis

Material extrusion (ME) 3D printing is an emerging technology to fabricate short carbon fiber reinforced SiC ceramic matrix composites (C_sf/SiC CMCs) with highly oriented short carbon fibers. In this study, the C_sf/SiC CMCs were fabricated by ME 3D printing combined with the following precursor infiltration and pyrolysis (PIP). The short carbon fibers could be well kept after the PIP process. The effects of solid loading and fiber content on the microstructure and mechanical properties of the C_sf/SiC CMCs were also investigated. Higher solid loading was beneficial for obtaining the denser C_sf/SiC CMCs with more oriented fibers. The introduction of short carbon fibers brought more pores. The bending strength and fracture toughness of C_sf/SiC CMCs first increased and then decreased with the increase in fiber content. The pulling-out and breakage of short carbon fibers contributed to the improvement of mechanical properties. High performance C_sf/SiC CMCs with a bending strength of 212.74 MPa and fracture toughness of 5.84 MPa m^1/2 were simultaneously achieved when the solid content was 50 vol% and the fiber content was 20 vol%. It is believed that this study can provide some understanding of the 3D printing of fiber reinforced CMCs.