R-CURVE EFFECT ON STRENGTH AND RELIABILITY OF TOUGHENED CERAMIC MATERIALS

An improved theoretical analysis is presented for the strength and mec hanical reliability of ceramic materials with an R-curve characteristi c. There is good agreement between the predicted flexural strength dis tribution of an Al2O3/ZrO2 ceramic and experimental data. Unlike the c onventional two-pa ra meter Weibull approach, this new ana lysis is ab le to predict the non-linearity observed in the InIn 1/(1-P-f) versus In sigma(f) strength distribution curve. Compared to the untoughened G riffith material, the R-curve material has higher strength and better strength reliability.