TEMPERATURE DEPENDENCE ON THE STRENGTH AND STRESS RUPTURE BEHAVIOR OF A CARBON-FIBER REINFORCED SILICON CARBIDE MATRIX (C/SiC) COMPOSITE

摘要

Tensile strengths and stress rupture lives of carbon- fiber reinforced silicon carbide (C/SiC) specimens were measured at 800 deg C and are compared to previously reported 1200 deg C data. All tests were conducted in an environmental chamber containing 1000 ppm of oxygen in argon. The average 800 deg C tensile strength of 610 MPa is 10 percent greater than at 1200 deg C. Average stress rupture lives at 800 deg C were 2.5 times longer than those obtained at 1200 deg C. The difference in the 800 and 1200 deg C lives is related to the oxidation rate of the reinforcing carbon fibers, which is the primary damage mode of C/SiC composites in oxygen-containing environments.