Determining worst-case fatigue thresholds for grain-bridging ceramics
- LBNL Library
A method for determining worst-case cyclic fatigue thresholds in grain-bridging ceramics by quantifying the role of bridging is demonstrated for a model alumina. Crack-growth properties for both long and short (< 2 mm) cracks emanating from machined notches (root radii, (rho) {approx}; 15 - 150 (mu)m) were investigated. When compared as a function of the applied stress-intensity range (delta K), growth rates (da/dN) were far higher and fatigue thresholds (Delta)KTH were markedly lower with short cracks, with growth being observable at the lowest driving forces for short cracks emanating from razor micronotches ((rho)is approximately equal to 15 (mu)m). For growth rates < 10-8 m/cycle, da/dN vs. (delta)K data for short cracks merged with the steady-state data for long cracks after {approx}2 mm of extension.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Director, Office of Science (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 805154
- Report Number(s):
- LBNL--51612; B& R KC0201030
- Country of Publication:
- United States
- Language:
- English
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