Evaluation of the elevated-temperature mechanical reliability of a HIPed silicon nitride
The long-term mechanical reliability of a commercially-available hot isostatically pressed silicon nitride was evaluated by measuring the tensile creep and fatigue behavior at 1150, 1260, and 1370{degrees}C. The stress and temperature sensitivities of the secondary (or minimum) creep rates were used to estimate the stress exponent and activation energy associated with the dominant creep mechanism. The fatigue behavior was examined by allowing individual creep tests to continue until the specimen failed. The applicability of the four-point load geometry to the study of creep behavior was also evaluated by conducting a limited number of flexural creep tests. The tensile fatigue data revealed two distinct failure mechanisms. At 1150{degrees}C, failure was controlled by a slow crack growth mechanism. At 1260 and 1370{degrees}C, the accumulation of creep damage in the form of grain boundary cavities and cracks dominated the fatigue behavior. In this temperature regime, the fatigue life was controlled by the secondary (or minimum) creep in accordance with the Monkman-Grant relation. 36 refs.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5770295
- Report Number(s):
- CONF-911050--4; ON: DE92007838
- Country of Publication:
- United States
- Language:
- English
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Evaluation of tensile static, dynamic, and cyclic fatigue behavior for a HIPed silicon nitride at elevated temperatures
Evaluation of tensile static, dynamic, and cyclic fatigue behavior for a HIPed silicon nitride at elevated temperatures
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Cermets
& Refractories-- Mechanical Properties
CERAMICS
CREEP
ENGINES
FABRICATION
FATIGUE
GAS TURBINE ENGINES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
MATERIALS WORKING
MECHANICAL PROPERTIES
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
PRESSING
RELIABILITY
SILICON COMPOUNDS
SILICON NITRIDES
TENSILE PROPERTIES