Mechanical properties of porous-matrix ceramic composites

The use of porous matrices to enable tolerance in ceramic composites has em erged as a new paradigm in high performance materials. This paradigm obviat es the need for fiber coatings for the purpose of crack deflection, thereby providing opportunities for lower cost manufacturing relative to that of c onventional coated-fiber systems. Furthermore, upon selection of all-oxide constituents, the prospect for meeting the long-term durability requirement s of high-temperatures components for the future gas turbine engine technol ogies becomes realizable. This article reviews the mechanical properties of this class of all-oxide composite. The properties of interest include the in-plane strength and notch-sensitivity subject to both fiber- and matrix-d ominated loadings, and interlaminar strength. Special emphasis is placed on the role of the porous matrix in each of these properties. Finally, the is sue of the stability of the matrix microstructure following prolonged expos ure at elevated temperature is addressed and its role in maintaining desira ble mechanical properties is demonstrated.