Creep and slow crack growth mechanisms related to macroscopic creep behaviour of a silicon nitride ceramic at elevated temperatures
- Oak Ridge National Lab., TN (United States)
- National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
Recent tensile creep and creep rupture test results of a hot isostatically pressed silicon nitride at 1150, 1260, and 1370{degrees}C were evaluated using microscopy in conjunction with various empirical and mathematical models to provide insight into creep and slow crack growth mechanisms. The stress and temperature sensitivities with dominant creep mechanism. Limiting cases for cavity nucleation and growth were applied to establish possible creep damage modes. At 1150{degrees}C, creep rupture 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 creep rupture behaviour. In this temperature regime, the creep rupture life was controlled by the secondary (or minimum) strain rate in accordance with a Monkman-Grant-type relation.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10150632
- Report Number(s):
- CONF-9206187--1; ON: DE92015195
- Country of Publication:
- United States
- Language:
- English
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