CRACK PROPAGATION BEHAVIOR AND LIFETIME PREDICTION IN ALUMINA AND ZIRCONIA

摘要

The lifetime prediction of ceramics is discussed on the basis of the relationship between stress intensity factor K_1 and crack velocity nu. The effects of water environment, the cyclic loading and microstructure of material on K_1-nu characteristics are studied by carrying out the crack growth tests by the double torsion (DT) method under the static and cyclic loading in both environments of air and water for alumina and zirconia. K_1-nu characteristics determined by the double torsion method are used to predict time-to-failure under the cyclic loading of alumina and zirconia ceramics. The predictions agree qualitatively with the experimental results.