Flexural strength and fracture toughness evaluations of fine ceramics at elevated temperature
- Univ. of Electro Communications, Tokyo (Japan)
- Mitsubishi Electric Co. Ltd., Fukushima (Japan)
Four-point bending tests were conducted on smooth and Vickers indentation notched specimens of alumina (Al2O3) and silicon nitride (Si3N3) at room and elevated temperatures (20 and {approx} 1400{degrees}C). The detailed observations of fracture surface of smooth specimens by a scanning electron microscope was carried out in order to identify the defect morphology at the fracture sites and to study the relation between the defect size and the flexural strength at room and elevated temperatures. The fracture toughness evaluation by a controlled surface flaw (CSF) method was also conducted on the two kinds of ceramics at room and elevated temperatures for Vickers indent notched specimens with different load conditions. Then, by introducing the assumed equivalent crack length, the relation between the strength and the crack size (including the small defect size) in the smooth and the notched specimens of two kinds of ceramics was evaluated in general by the concept of fracture mechanics at room and elevated temperature in the conditions of this study.
- OSTI ID:
- 563616
- Report Number(s):
- CONF-9606176--
- Country of Publication:
- United States
- Language:
- English
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