Abstract
This paper describes the fatigue crack growth characteristics of Si3N4 in cyclic three point bending test which is required in the reliability evaluation and prediction of the life of ceramic component. Extensive crack growth is observed prior to the final fracture during cyclic loading. It is confirmed that Si3N4 exhibits a linear relationship on logarithmic scale between the fatigue crack growth rate and the stress intensity factor range. Statistical characteristics of the crack growth parameters m, C and fatigue fracture toughness value Kf, are discussed based on goodness-of-fit test for three types of distribution functions of normal, Weibull and Type I extreme value, and these variables are found to fit Weibull distribution best. It is found that the estimated life of Si3N4 components decreases with increasing stress range and initial crack length and with decreasing fracture probability.
