Abstract
Al_2O_3/SiC composite ceramics was sintered by hot pressing. Three point bend tests were conducted according to JIS standard. Semi-elliptical surface crack of 40-350μm in diameter was made on the specimen. Four kinds of specimens (as-received, heal treated, pre-cracked and heal treated cracked), crack healing behavior and high temperature strength were tested systematically. The main conclusions were obtained as follows : (a) Al_2O_3/SiC composite ceramic has ability to heal crack. (b) Pre-cracked Al_2O_3/SiC composite ceramic to be healed completely at 1273K, 1473K and 1573K, for 300h, 10h and 1h, in air each other. (c) The maximum crack size to be healed is semi-elliptical crack of about 300μm in diameter. (d) Crack healed part has approximately the same strength of smooth specimen up to 1373K and most specimen failed outside the pre-cracked zone.
