Fabrication and characterization of SiCf/SiC composites produced by the slurry infiltration process

The mechanical properties of SiCf/SiC composites have been investigated, based on detailed analyses of their microstructure. SiCf/SiC composites were prepared from fiber preforms by a slurry infiltration technique, in which a mixture with SiC, Al2O3, and Y2O3 particles was impregnated into the fabric structure. SiCf/SiC composites were consolidated by liquid phase sintering process, associated with the creation of secondary phases by the addition of Al2O3 and Y2O3 particles. The reinforcing material was a plain weave Tyranno SA SiC fabric with a carbon interfacial layer. The sintered density and the pore volume fraction of SiCf/SiC composites were about 3.0 Mg/m3 and about 10%, respectively. These SiCf/SiC composites had an average flexural strength of about 250 MPa at room temperature. They exhibited pseudo-ductile fracture behavior, due to the carbon interfacial layer. The introduction of the carbon interfacial layer greatly improved the fracture energy of SiCf/SiC composites.