Stress rupture in tension and flexure of a SiC-whisker-reinforced silicon nitride composite at elevated temperatures

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1996.tb09053.x· OSTI ID:413332

Zhu, Shijie ^[1]; Mizuno, Mineo; Nagano, Yasuo ^[1]; Kagawa, Yukata ^[2]; Watanabe, Makoto ^[3]

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1. Japan Fine Ceramics Center, Nagoya (Japan)
2. Univ. of Tokyo (Japan). Inst. of Industrial Sciences
3. Petroleum Energy Center, Tokyo (Japan)

Stress rupture of a 20 vol% SiC whisker-reinforced Si{sub 3}N{sub 4} composite processed by gas pressure sintering was investigated by both tension and flexure methods. The stress exponents for the stress rupture decrease with increasing temperature. The fracture surfaces of both tensile and flexural stress rupture at 1,000 C consist of mirror, mist, and hackle regions. The size of the mirror region increases with decreasing stress. Crack propagation is a mixture of intergranular and transgranular modes at 1,000 C. Both tensile and flexural fracture surfaces under constant stress at 1,200 C were characterized by a rough zone and a mirror zone; the size of the rough zone increased with decreasing stress. Creep crack growth occurred at 1,200 C, which is a process of cavity nucleation, growth, and interlinkage in front of a crack. The transition of fracture mechanisms with temperature is discussed.

• Sponsoring Organization: USDOE
• OSTI ID: 413332
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 10 Vol. 79; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
CRACK PROPAGATION
CRACKS
EXPERIMENTAL DATA
FLEXURAL STRENGTH
FRACTOGRAPHY
GRAIN BOUNDARIES
MICROSTRUCTURE
OPTICAL MICROSCOPY
POROSITY
SCANNING ELECTRON MICROSCOPY
SILICON CARBIDES
SILICON NITRIDES
SINTERING
STRAINS
STRESSES
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES