Fatigue Strength and Fracture Mechanisms of Porous Silicon Carbide
Akio YONEZU, Takeshi OGAWA and Hiroshi KAWAMOTO
Abstract:Static and cyclic fatigue strength in porous SiC ceramics were evaluated using quasi-static and cyclic tests, I.e. load, P, increasing and load range, ƒ¢P, increasing tests, respectively. The evaluation method used Weibull distribution, in which the fracture parameters are stress at failure, ƒÐf, for quasi-static loading and maximum stress at failure, ƒÐmax,f, for cyclic loading. The results revealed that the static fatigue behavior had an important role on the fatigue strength. Statistical characteristics of the fatigue strength were expressed by P-S-N curve estimated by the results of ƒ¢P-increasing tests. During the fatigue experiments, crack nucleation was detected using acoustic emission (AE), and the fracture surfaces were observed by SEM. Based on these results, fracture mechanism of the porous SiC ceramics was discussed in detail. Key Words:Fatigue strength, Fracture mechanism, Porous silicon carbide, Static fatigue, Cyclic fatigue, Acoustic emission, Weibull statistics