Long-Term Creep and Creep Rupture Behavior of Woven Ceramic Matrix Composites at Elevated Temperatures

The strong interest in ceramic matrix composite for high temperature application arises primarily from their ability to retain good creep behavior. The objective of this work is to investigate the creep behavior of quasi-isotropic woven silicon carbide fabric reinforced silicon-nitrogen-carbon (SiC/SiNC) ceramic composite at stress levels which are above and below the monotonic proportional limit strength. Constant-load tensile creep-rupture tests were performed on SiC/SiNC ceramic matrix composite on an Instron 8502 material test system. The creep behavior of SiC/SiNC matrix composites were investigated at various temperatures (700°C and 1000°C) and stress levels (55%, 65% of ultimate strength, σ_ult). The strain vs. time curves consisted of primary and secondary (steady state) creep regions were established. The stress exponent and activation energy of SiC/SiNC ceramic matrix composite were also determined at these temperatures. The creep data followed the traditional power law exhibiting an exponential relationship between creep rate and stress.