Stress-Rupture, Overstressing and a Proposed New Methodology to Assess the Durability and Reliability of Ceramic Matrix Composites at Elevated Temperatures

摘要

A new testing strategy is proposed to assess the durability and reliability of non- oxide continuous fiber-reinforced ceramic composites for high temperature structural applications. The strategy is based on determining the reliability (probability of failure) of these materials when subjected to random loading schedules consisting of load and temperature spikes that are superimposed on otherwise constant stress and temperature histories. The frequency and magnitude of the load and temperature spikes would be representative of the number and characteristics of the transients that are associated with a particular industrial application and that are expected to occur over the life of the component. The effect of overstressing on the stress- ruptttre behavior of a CG-NicalonTM fiber-reinforced SiC composite was investigated and results arc presented from tests conducted in ambient air at 950 deg C.