抄録
Mullite/SiC whiskers/ SiC particles multi-composite, having excellent crack-healing ability and mechanical properties, was hot-pressed in order to investigate the crack-healing behavior under stress and resultant fatigue strength at the temperature of healing. To actualize ceramic components made of the multi-composite, it is necessary to know threshold stress for crack-healing. A semi-elliptical surface crack of 100μm in surface length was made on each specimen. The pre-cracked specimens were crack-healed under cyclic or constant stress by using three-point bending stress at 1200℃, and the resultant bending strength and cyclic fatigue strength were investigated at 1200℃. The pre-crack on the surface of specimens could be healed even under stress. The threshold stresses for crack-healing, determined by evaluating strengths of crack-healed specimens at healing temperature of 1200℃, were found to be 170MPa for both constant and cyclic stresses, corresponding to 80% of bending strength of the pre-cracked specimens. The static and cyclic fatigue strengths of crack-healed specimens were also investigated at healing temperatures of 1200℃.
