Weibull master curves and fracture toughness testing Part II Evaluation of data of quasi-static three-point bend tests of tetragonal zirconia, zirconia/alumina and silicon nitride

Abstract

It has already been displayed that a variety of apparent fracture toughness master curves and Weibull master curves exist, which enables an extensive description of the fracture toughness of the investigated solids. Therefore, the concept of Weibull master curves has been generalized. In this paper, it is shown that characteristic magnitudes, derived from both experimental Weibull master curves and experimental apparent fracture toughness master curves, can be defined in a new way, by quantifying the amount of microcracking and crack-tip shielding that occurs when materials undergo stable crack growth prior to failure (when a sufficient external load is applied). Experimental data of three-point bend tests of ceria partially stabilized tetragonal zirconia, yttria partially stabilized zirconia/β-alumina-composite, and coarse-grained β-silicon nitride gathered at room temperature have been evaluated. The Weibull master curves, which are obtained by scaling the cumulative failure distribution functions with the corresponding mean-values, have been found to be most appropriate for investigating the fracture toughness by quasistatic uniaxial tensile or bend tests.