Interface degradation in CAS/Nicalon during elevated temperature aging
- Oak Ridge National Lab., TN (United States)
- Univ. of Warwick, Coventry (United Kingdom). Centre for Advanced Materials Technology
A CaO-Al{sub 2}O{sub 3}-SiO{sub 2} (CAS)/Nicalon glass-ceramic matrix composite has been subjected to elevated temperature oxidation heat-treatments between 375 and 1200{degrees}C, for up to 100 hours. Micro- and macro-mechanical properties have been determined by fiber push-down, using a mechanical properties microprobe, and flexure testing, respectively. Aging between 450 and 800{degrees}C results in significant property degradation, with reduced bending modulus and flexure strength, increased fiber sliding stress, and a transition to a purely brittle failure mode. Aging degradation is due to oxidative removal of the carbon interlayer, with the subsequent formation of a silica bond between fiber and matrix. At higher temperatures, carbon is retained due to the formation of a protective silica plug at exposed fiber ends, with the subsequent retention of composite properties. Short duration pre-treatment schedules, at 1000 or 1100{degrees}C, were developed to prevent intermediate temperature property degradation.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); European Economic Community, Brussels (Belgium)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 39120
- Report Number(s):
- CONF-941144--115; ON: DE95008843
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AGING
ALUMINIUM OXIDES
BENDING
CALCIUM OXIDES
CERAMICS
CHEMICAL VAPOR DEPOSITION
COMPOSITE MATERIALS
FLEXURAL STRENGTH
HEAT TREATMENTS
INTERFACES
MATRIX MATERIALS
MECHANICAL PROPERTIES
OXIDATION
REINFORCED MATERIALS
SCANNING ELECTRON MICROSCOPY
SILICON OXIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY SPECTRA