Composite Materials, Ceramic‐Matrix

Abstract

Ceramic‐matrix composites are materials for use in high temperature structural applications. The intrinsic properties of the ceramic‐matrix such as high melting point, high chemical stability, high elastic modulus and hardness, high wear and creep resistance along with low mass density relative to metallic materials are coupled with the properties of high fracture resistance and flaw insensitivity when reinforced with a high strength second phase. The varieties of reinforcements include particles, platelets, whiskers, and continuous fibers. Placement of reinforcements within the matrix determines the isotropy of the composite properties. Particulate reinforced matrices derive their toughness from processes such as crack deflection, crack pinning and bowing, microcracking, and frictional bridging mechanisms. Whisker, platelet, and fiber‐reinforced matrices derive their toughness from crack‐wake frictional bridging and pull‐out mechanisms. For the mechanism of crack‐wake bridging the most important aspect of the composite is the interface between the reinforcement and the matrix. It must be weak enough to allow debonding around the reinforcement leaving it as an intact bridging element in the crack‐wake. Control of the interface between the matrix and reinforcements is extremely important in optimization of composite properties.