Tensile creep and creep rupture behavior of monolithic and SiC-whisker-reinforced silicon nitride ceramics

Journal Article · Wed Dec 01 04:00:00 EST 1993 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1993.tb06615.x· OSTI ID:5381100

Ohji, Tatsuki; Yamauchi, Yukihiko ^[1]

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1. National Industrial Research Inst. of Nagoya (Japan)

The tensile creep and creep rupture behavior of silicon nitride was investigated at 1,200 to 1,350 C using hot-pressed materials with and without SiC whiskers. Stable steady-state creep was observed under low applied stresses at 1,200 C. Accelerated creep regimes, which were absent below 1,300 C, were identified above that temperature. The appearance of accelerated creep at the higher temperatures attributable to formation of microcracks throughout a specimen. The whisker-reinforced material exhibited better creep resistance than the monolith at 1,200 C. Considerably high values 3 to 5, were obtained for the creep exponent in the overall temperature range. The exponent tended to decrease with decreasing applied stress at 1,200 C. The primary creep mechanism was considered cavitation-enhanced creep. Specimen lifetimes followed the Monkman-Grant relationship except for fractures with large accelerated creep regimes. The creep rupture behavior is discussed in association with cavity formation and crack adolescence.

• OSTI ID: 5381100
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 76:12; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
CARBIDES
CARBON COMPOUNDS
COMPOSITE MATERIALS
CREEP
FAILURES
MATERIALS
MECHANICAL PROPERTIES
RUPTURES
SILICON CARBIDES
SILICON COMPOUNDS
TEMPERATURE DEPENDENCE