Mechanism of mechanical fatigue of silica glass
Research continued on the mechanism of mechanical fatigue of silica glass. Significant accomplishments this quarter include: strength increase of abraded glasses by thermal and chemical treatments was found best explained by crack tip blunting; fatigue was found to involve crack initiation in addition to crack propagation, and only water and ammonia were found capable of causing crack initiation from blunt crack tips at sub-critical stresses; water was found to enter into silica glass during microhardness indentation as well as during slow crack growth in water-containing atmospheres at room temperature; water diffusion at low temperature showed anomalous phenomena including initial time dependences of solubility and apparent diffusion coefficient; glass containing water showed greater fatigue susceptibility and lower crack initiation stress than dry glass; fatigue of abraded silica glass showed effects of cyclic stress when tested by the rotation bending method while no cyclic stress effect was observed in reciprocal bending; and a new coating which can reduce fatigue of silica glass was developed.
- Research Organization:
- Rensselaer Polytechnic Inst., Troy, NY (USA). Dept. of Materials Engineering
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- FG02-85ER45217
- OSTI ID:
- 6480692
- Report Number(s):
- DOE/ER/45217-T1; ON: DE91004053
- Country of Publication:
- United States
- Language:
- English
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