Thermal Fatigue Resistance of a Carbon-Carbon Composite

Abstract

Thermal fatigue resistance of carbon-carbon composites with three different fiber surface treatments is studied in thermal cycles between 100 °C and 1,700 °C up to a number of cycles of 100 in free and restricted expansion conditions. The effects of thermal cycles were studied by SEM paying attention especially to structural damage and interfacial debonding between fibers and matrix. Bending tests subsequent to 10 thermal cycles were used to study the effect of thermal cycling on mechanical properties of the composites. The effect depends on the surface treatment of fibers prior to pyrolization. In some cases, the bending strength decreased due to the thermal cycling, whereas a suitable surface treatment minimized the damaging effect and increased the pseudo-ductility of the composite.