Stressed Oxidation Life for a Carbon Fiber Reinforced Silicon Carbide Matrix Composite

Abstract

Stress-rupture life and residual strength results obtained for a carbon fiber reinforced silicon carbide matrix composite are presented. The material used in this study had a chemical vapor infiltration silicon carbide matrix reinforced by T-300 carbon fibers in a two-dimensional woven cloth, with a plain weave architecture. Tests were conducted in a reduced oxygen environment of 1000 ppm O2/Ar at 1200 °C. The results from two sets of twenty creep rupture tests performed at a fixed stress are presented and discussed. In the first test set, specimens were run to failure. In the second set, rupture testing was interrupted after a fixed time interval and retained strengths were then measured. The results of this study reveal a simple deterministic relationship between the retained strength and residual life of the ceramic composite when exposed to the oxidative environment. Creep life was also observed to increase for specimens with wider tests section widths. Microstructural examination revealed damage mechanisms in the form of fiber oxidation and this points to the need for developing environmental models for predicting life of a component manufactured with this material.