Alumina ceramic reinforced by SiC whisker was sintered. Three point bending specimen was made from the composite ceramic. A semi-elliptical surface crack up to 450μm in diameter (aspect ratio≈0.9) was introduced on the specimen. Basic crack-healing behavior of the cracked-sample was studied systematically as a function of crack-healing temperature, and also bending strength of crack-healed sample was tested systematically. Followings are main conclusions obtained; (1) Alumina reinforced by SiC whisker exhibited large crack-healing ability. (2) The fracture toughness KIC of the composite alumina was increased by the SiC whisker reinforcement considerably as compared with alumina reinforced by SiC particles. (3) The crack-healed alumina exhibited the same level bending strength (σB) as the base material and very high σB up to 1473K. (4) The alumina was able to heal the crack even under cyclic stress at 1473K, and the critical stress intensity factor (KHSC) was found to be 3.8MPa √m.
