Stress/life behavior of a C/SiC composite in a low partial pressure of oxygen environment Part I: static strength and stress rupture database

摘要

Tensile strengths and stress-rupture lives were obtained for carbon fiber-reinforced silicon carbide (C/SiC) composite specimens. The testing was performed at 1200 °C in an environment of 1000-ppm oxygen, with argon as the remaining gas. Twenty tensile tests were conducted. The stress-rupture database includes over twenty test results, with test stresses in the range of 276 to 100 MPa resulting in lives in the range of 4 to 160 hours. All specimens were machined from a single material lot. Plate-to-plate variability of tensile strength and stress-rupture lives was observed and is discussed. Also, the creep strain data was a function of stress and plate ID is presented. During the stress-rupture testing of C/SiC specimens, the partial pressure of O_2 flowing out of the chamber was monitored and found to vary as a function of test time for any given test. The effluent partial pressure of O_2 varied with test stress and these results are presented as well.