Characterization of pore evolution in ceramics during creep failure and densification: Progress report
Rice has pointed out that the failure of ceramics is a weak link process, and that frequently, the number, distribution, size(s), and shapes of inherent pores within a ceramic body constitute its principal weak links. General (average) porosity has been specifically identified as a controlling parameter in compressive failure under ambient conditions, and since local compressive failure usually is involved in wear, particle impact, and abrasive damage modes, average porosity should be very important under these circumstances as well. However, porosity-induced tensile failure at low homologous temperatures is concerned with largest pore, or pore cluster, sizes. On the other hand, failure of ceramics during creep at elevated temperatures, under all states of stress, is very sensitive to average porosity; such failure involves the nucleation, growth, and eventual coalescence of multiple pores. Creep lifetime prediction, therefore, involves the estimation of the kinetics of the latter cavitation processes. In this report, experimental evidence concerning the creep failure of high strength ceramics will be reviewed, and theoretical failure models will be outlined. By analyzing the predictions of the models, parameters which should exert primary control over failure can be specified. Consideration of these factors will establish the experimental test conditions which should permit discrimination between competing theoretical possibilities. Pore evolution during sintering/processing will be discussed. 95 refs., 1 fig.
- Research Organization:
- Southwest Research Inst., San Antonio, TX (USA)
- DOE Contract Number:
- FG05-84ER45063
- OSTI ID:
- 5978847
- Report Number(s):
- DOE/ER/45063-1; ON: DE89016275
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Characterization of pore evolution in ceramics during creep failure and densification. Final report, April 15, 1984--April 14, 1995
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Related Subjects
CERAMICS
POROSITY
CREEP
FAILURES
CAVITATION
DENSITY
MATERIALS TESTING
NUCLEATION
PROCESSING
PROGRESS REPORT
SINTERING
TENSILE PROPERTIES
DOCUMENT TYPES
FABRICATION
MECHANICAL PROPERTIES
PHYSICAL PROPERTIES
TESTING
360203* - Ceramics
Cermets
& Refractories- Mechanical Properties
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360201 - Ceramics
Cermets
& Refractories- Preparation & Fabrication