Effects of ceramic layer height on the mechanical properties of C_f/SiC ceramic matrix composites fabricated by fiber-laying-assisted material extrusion 3D printing

Tradition fabrication methods of continuous carbon fiber reinforced SiC ceramic matrix composites (C_f/SiC CMCs) cannot meet the requirements of complex structures. In this research, C_f/SiC CMCs were fabricated through a novel technology combined with fiber-laying-assisted material extrusion (ME) 3D printing with precursor infiltration and pyrolysis (PIP). The ME system was utilized to produce SiC slurry, while the fiber-laying system was employed to embed continuous carbon fibers, resulting in the integrated fabrication of C_f/SiC CMC green bodies. Then C_f/SiC CMCs underwent the PIP process to achieve densification. The impact of ceramic layer height on the microstructure and mechanical performance of 3D-printed C_f/SiC CMCs was thoroughly examined. The gaps between continuous carbon fibers and SiC ceramic matrix could be reduced by lowering the ceramic layer height. The obtained C_f/SiC CMCs showed delayed fracture behaviors. As the ceramic layer height increased, both the bending strength and fracture toughness initially improved before declining. High performance C_f/SiC CMCs with a bending strength of 288.49 MPa and a fracture toughness of 15.19 MPa m^1/2 were simultaneously obtained when the ceramic layer height was 0.75 mm. This work can provide novel insights into the 3D printing of fiber reinforced ceramic matrix composites.