Accession Number : ADA302277

Title :   High-Temperature Creep of Carbon Yarns and Composites.

Descriptive Note : Technical operating rept.,

Corporate Author : AEROSPACE CORP EL SEGUNDO CA MATERIALS SCIENCES LAB

Personal Author(s) : Feldman, L. A.

PDF Url : ADA302277

Report Date : 30 SEP 1987

Pagination or Media Count : 60

Abstract : Effects of creep and deformation at high temperatures in carbon-carbon composites have been investigated. High-temperature creep in composites may play an important role in processing, through relaxation of thermally induced stresses caused by thermal expansion anisotropy of graphite. Creep has been measured in unidirectional composites at temperatures between 2000 and 3000 C. Various distinctions have been observed among the creep behaviors of composites utilizing PAN-, rayon-, and mesophase-pitch-based carbon fibers, such as decreasing creep rates and elongations with increasing stiffness and degree of graphitic disorder. Fiber-matrix debonding at high temperature, such as that in microstructural observations using SEM, occurs after high-temperature deformation and is visible in the interior of microcracks and at fracture ends. Estimates of relative thermal expansion coefficients of different fiber composites under low stress in the creep regime have been obtained. (MM)

Descriptors :   *CARBON CARBON COMPOSITES, *CREEP, *CARBON YARN, VIBRATION, SCANNING ELECTRON MICROSCOPES, MICROSTRUCTURE, COMPOSITE MATERIALS, HIGH TEMPERATURE, DEFORMATION, STIFFNESS, DISPLACEMENT, FIBER REINFORCED COMPOSITES, ORDER DISORDER TRANSFORMATIONS, GRAPHITE, CARBON FIBERS, FRACTURE(MECHANICS), THERMAL EXPANSION, ANISOTROPY, FILAMENTS, ROCKET ENGINES, THERMAL STRESSES, ELONGATION, ACTIVATION ENERGY, MICROCRACKING.

Subject Categories : Refractory Fibers
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE