The thermal expansion of carbon/carbon composites from room temperature to 1400 °c

The influence of heat treatment, preform architecture, and the microstructure of the matrix carbon on the coefficient of thermal expansion (CTE) of carbon/carbon composites was analyzed. The CTE of the densified composites was measured parallel and perpendicular to the fiber cloth layer, or the random short fiber layer, from room temperature to 1400 ° C in an argon atmosphere. These composites possess turbostatic graphite structure, which can be transformed from turbostatic graphite into hexagonal crystal, with increase in the heat treatment temperature. The CTE found to be anisotropic and decreases with the heat treatment temperature increasing. The results show that the thermal expansion of pyrocarbon with a smooth laminar texture is smaller than that of pyrocarbon with a rough laminar texture under the same conditions.