EFFECT OF GRINDING ON FATIGUE BEHAVIOR OF CERAMICS AT AMBIENT-TEMPERATURE

The decrease in the fatigue parameter n of ground ceramics and its eff ect on lifetime were discussed. The decrease was observed in dynamic f atigue tests of nonoxide ceramics containing a glassy phase and of oxi de ceramics. It is considered that the decrease in n value is mainly d ependent on the degree of stress corrosion due to water vapor. We also revealed that the decrease in the ii value can be Prevented by contro lling the grain depth of cut g below a critical value (g(cr))(f). The static fatigue test of ground ceramics was also carried out and the sh ortening of lifetime was observed, although the strength degradation w as small.