セラミックスの常温における繰返し疲労挙動(<小特集>粉体小特集)

概要

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The cyclic fatigue behavior of different kinds of ceramics was investigated at room temperature. Flexural specimens, with an indentation induced flaw at the center of the reduced gage section, were tested under a cyclic load applied by four-point bending. All ceramics tested were shown to be susceptible to cyclic fatigue failure. The cyclic fatigue degradation compared to its flexural strength increased in this order: hot-pressed AIN, sintered SiC, hot pressed Si_3N_4, sintered Si_3N_4, and sintered Al_2O_3. The apparent fatigue limit was about 80% of average flexural strength for AIN, and about 60% for sintered Al_2O_3. There existed a correlation between the scatter in fatigue and flexural strength. The scatter in fatigue strength was smaller than the scatter in flexural strength. SEM fractography revealed a dominant intergranular fracture in Al_2O_3 and Si_3N_4, which suggests a possible stress corrosion cracking mechanism in the grain boundary glassy phase. On the other hand, hot-pressed AIN showed a mixed mode fracture of intergranular and transgranular cracking, and SiC exhibited transgranular cracking only.
社団法人日本材料学会の論文
1987-11-15