About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
Acta Metallurgica Et Materialia
Paper
Segregation effects in the fracture of brittle materials: CaAl2O3
Abstract
The fracture properties of the model ceramic system CaAl2O3 have been studied by strength measurements at controlled flaw sizes and direct observations of crack propagation, with a view to determining the effect of grain-boundary Ca segregation. In contrast to the assumptions of previous works the fracture properties are not controlled by the grain-boundary properties alone, but by an increasing toughness with crack extension, a T-curve, observed in all the microstructural variations examined (changing grain-size and grain-boundary Ca concentration). The origin of the T-curve is identified as the formation and subsequent rupture of ligamenting bridges of material, acting as restraining elements behind the crack tip. Models of the bridging process are developed to quantify the T-curves underlying the observed strength behavior, highlighting the equal roles played by the intrinsic interfacial (grain-boundary) properties, and the toughening mechanisms, in determining the overall fracture response of these and similar polycrystalline materials. © 1990.