Re-Entry and Environmental Systems Division, General Electric Company, Philudelphia, Pennsylvania) and J. D. Latva (Air Force Ma&riuLs L&oratory, Wright-Patterson Air Force Base, Ohio). Multi-directional reinforced carbon-carbon
composites that employ graphite fibers oriented in several principal directions (3,4 or 7) have been developed in programs sponsored by the Air Force Materials Laboratory at the Re-Entry and Environmental Systems Division of the General Electric Company.
130. Practical carbon-carbon composite structures
J. Hill, C. R. Thomas and E. J. Walker (Chemical Technology Division, Atomic Weapons Research Establishment, Aldermaston, Reading RG7 4PR, England). Some experimental approaches are described to improve the transverse properties of carbon fibre reinforced carbon composites by the introduction of auxiliary fibres at an angle to the principal fibre direction. Sandwiches of unidirectional fibre with woven cloth, and unidirectional fibre with short fibre felts gave suitable combinations of properties.
131. Pyrocarbon formation from benzene in the preparation of carbon-carbon composites*
R. M. Curlee and M. L. Lieberman (Sandti Laboratories, Albuquerque, New Mexico). Carbon matrices prepared by pyrolysis of benzene and methane in filamentary substrates are compares. The data show that identification of the matrix optical microstructure is not sufficient to define composite properties in a given substrate. Infiltration from benzene pyrolysis appears to offer some advantages over methane pyrolysis. *This work was supported by the United States Atomic Energy Commission. 132. Effects of compaction on the properties of carbon felt-carbon matrix conical frusta* B. Granoff and M. P. Apodaca (Sandra Laboratories, Albuquerque, New Mexico). Carbon felt-carbon matrix conical frusta were fabricated by the chemical vapor deposition of carbon within carbonized viscose rayon substrates. The effects of fiber volume on the thermal and mechanical properties were evaluated by compacting one of the felt substrates prior to carbonization. Increases in fiber content resulted in: (1) a decrease in porosity, (2) filament and matrix reorientation, (3) increases in axial and hoop tensile strengths and (4) increases in anisotropy. *This work was supported by the United States Atomic Energy Commission.
133. Carbon-carbon composites: the effects of processing parameters on properties
J. Hill and E. J. Walker (Chemical Technology Division, Atomic Weapons Establishment, Alderma.stm, Reading RG7 4PR, England). The paper describes experimental investigations into the factors which are important in controlling the properties of carbon-carbon composites. Moulding conditions, governing porosity in the fibre-resin condition; gas flow rates and pressures controlling densification by vapour deposition and the ultimate heattreatment temperature all affect the final composite properties.
134. Properties of carbon/carbon filament wound composites with laminar and isotropic matrix microstructures*
R. M. Curlee and D. A. Northrop (Sandia Lubomtories, Albuquerque, New Mexico). The mechanical and thermal properties of carbon/carbon filament-wound composites with laminar and isotropic matrix microstructures have been compared. Strengths of these composites are not influenced by matrix microstructure, but thermal properties measured in the filament direction reflect the matrix preferred orientation of the laminar structure.