Creep Performance of Oxide Ceramic Fiber Materials at Elevated Temperature in Air and in Steam

The effects of steam on the creep performance for several ceramic materials were investigated at temperatures in the 1100-1300 deg. C range. Experimental programs were designed to explore both tensile and compressive creep behaviors as well as the response in monotonic tension. Subcritical crack growth was determined to be the dominant failure mechanism in ceramic fibers at elevated temperatures in steam. The creep life prediction analysis of ceramic fiber tows was performed using linear elastic fracture mechanics and a power-law crack velocity model. Additionally, the effects of steam at 1300 deg. C on creep performance of high-purity polycrystalline yttrium aluminum garnet (YAG) were studied. The high temperature mechanical properties of polycrystalline YAG make it the most promising candidate material oxide material for the next generation ceramic fibe