MECHANICAL PROPERTIES OF CERAMIC MATERIALS

The strength and fracture behaviour of ceramics are considered with particular reference to oxides. Ceramics fracture in a brittle manner and the strength of most materials is about two orders of magnitude less than the theoretical strength. Strength is discussed conveniently in terms of a modified Griffith equation and the important variables are an effective surface energy and an initial crack size. Both these variables can be related to microstructural features. The effective surface energy is relatively insensitive to structure. The Griffith crack size is more dependent on structure but the controlling factors are only partly understood. Further advances require more detailed information about the role of grain and phase boundaries and the relationship to Griffith cracks. © 1969, Taylor & Francis Group, LLC. All rights reserved.