Mechanisms of Toughening in Ceramic Matrix Composites

Abstract

Mechanisms of toughening of ceramic composites are reviewed from several perspectives, with the overall goal of providing guidance in composite development. Some theoretical concepts are used but are not the focus of the paper. The first perspective is an evaluation of why previous ceramic composites approaches were not particularly successful. Mechanisms of composites that are or may be useful are reviewed, followed by a discussion of how these mechanisms can be combined. Finally, cautions based on possible limitations, especially fatigue-type effects, in some composites are noted, along with the need for more thorough characterization. The central theme is that ceramic composites offer an important and challenging opportunity. Further, both particulate and fiber composites and combinations of these are important. All appear best when the dispersed phase is fine in size or diameter, closely spaced (i.e. a high numerical density), and preferably geometrically ordered in the body.