R-CURVE BEHAVIOR AND THERMAL-SHOCK RESISTANCE OF CERAMICS

The influence of R‐curve behavior of ceramics on the strength degradation associated with thermal shock is explored. Of particular significance for this interdependence is the observed nonlinear stress‐strain behavior of materials that exhibit minimal strength degradation under severe thermal shock conditions. These two features, R‐curve behavior and nonlinear behavior, are incorporated into a fracture mechanics analysis to provide a framework with which to understand severe thermal shock of ceramics. This analysis enables the estimation of the crack growth due to thermal shocking and also the anticipated strength degradation. The influence of specimen size is also addressed, and it is shown that greater strength degradation is anticipated with increasing specimen size. Experimental results for an alumina‐zirconia composite material are presented to support the simple analysis. Copyright © 1990, Wiley Blackwell. All rights reserved