Stability of Oxides in Metal or Metal Alloy Matrices.
Abstract
The objective of the program was to conduct a study of the chemical interaction between Tyco single-crystal sapphire filaments and nickel and nickel alloys, and to determine the effects of these reactions on filament and composite strength. During the first year's work on this contract, the reactions between sapphire and nickel, nickel-chromium, and U-700 were studied in both air and hydrogen, and the effect of these reactions on extracted filament strength was determined. During the present contract period, the emphasis was placed on the effect of filament-matrix reactions on the transverse and longitudinal strength of sapphire-nichrome composites. A determination of the in-situ strength of sapphire filaments in nichrome revealed that the strength was about that of the as-received filaments. This verifies the conclusion drawn after the chemical reactivity studies performed last year, where the attack by nichrome on sapphire was very much less than that in the case of nickel. Because of this lack of strength degradation during composite fabrication, the NiCr/Al2O3 system seems to possess considerable potential as a composite system. It was found, irrespective of the treatment given to the composites, that the sapphire-matrix bond was weak. Sputtering titanium on the sapphire did not seem to appreciably increase the transverse strength, but only very thin coatings were applied. In actual use, of course, proper composite design such as the judicious use of cross plies could reduce the severity of this problem. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1971
- Accession Number
- AD0727781
Entities
People
- R. L. Mehan
- T. A. Harris
Organizations
- General Electric