Three types of structural ceramics, Al
2O
3/SiC, mullite/SiC and Si
3N
4/SiC having excellent crack-healing ability were sintered. A semi-elliptical surface crack of 75-110μm in surface length was made on each specimen with a Vickers indenter. The basic crack-healing behavior was studied systematically on Al
2O
3/SiC as a function of crack-healing temperature and time. Three point bending tests were carried out to investigate the strength of crack-healed samples. The specimens containing the semi-elliptical surface crack were healed under static or cyclic bending stress on mullite/SiC and Si
3N
4/SiC. It was shown that a crack could be healed completely either under a static or a cyclic stress. The competition between self crack-healing rate (
SCHR) and crack growth rate (
CGR=d
a/d
t) determines the crack-healing behavior under stress: (i) In case of
SCHR>
CGR, a crack can be healed completely even under stress and recover of strength is complete. (ii) In case of
SCHR≅
CGR, a crack cannot be healed completely and recover of strength is insufficient. (iii) In case of
SCHR<
CGR, the specimen fails due to crack growth under stress.
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