Estimation of Weibull modulus from coarser defect distribution in dry-pressed alumina ceramics

Strength variation of alumina ceramics formed by dry-pressing of granules was examined by the number density of coarser defects. The Weibull modulus m was related to the exponent n of the power function of the number density of coarser defects by strength simulation; m = 1.82n - 1.92. The Weibull modulus was determined by a series of strength data, which were calculated by the simulated bending tests of the samples. The number density of coarser defects was given by the assumed power function. The various Weibull moduli were obtained for some kinds of series. The experimental results of the number density of coarser defects by direct observation of alumina ceramics and the Weibull modulus from strength tests were plotted well on the calculated line except a series of sample containing coarser defects with ambiguous boundaries. The relationship between the Weibull modulus and the parameter of the power function concurred with past studies; m = 2n - 2.