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Abstract:
A new type of composite, which consists of a reinforcement phase plus a matrix composed of many alternate thin layers of two different materials, has been prepared. CVI appears to be an appropriate process for the fabrication of this class of materials. We have successfully fabricated such a composite using the forced flow-thermal gradient CVI process. A carbon 2-D cloth preform was infiltrated with alternate layers of C and SiC having thicknesses of 0.01 to 0.5 micrometers Composites containing inexpensive SiC particles or platelets rather than fibrous reinforcement were also prepared. For a fixed cycle time, layer thicknesses increased with distance from the fiber surface. Crack deflection patterns indicate that the laminated matrix may contribute to mechanical toughness. The latter half of the project emphasized the CVD of Ti3SiC2 which may be a useful fiber matrix interface coating and/or matrix material. Ti3SiC2 was successfully deposited onto graphite substrates, and more recently on C and SiC cloth substrates. The reagent system TiCl4-SiCl4-CCl4-H2 was used.
| Limitations: |
 APPROVED FOR PUBLIC RELEASE |
| Description: |
Final rept. |
| Pages: |
51 |
| Report Date: |
28 OCT 1999 |
| Contract Number: |
F49620-96-1-0321 |
| Report Number: |
A505173 |
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