High temperature compressive strength and creep behavior of Si-Ti-C-O fiber-bonded ceramics

Journal of the European Ceramic Society, 37 (2017) 4442-4448

High temperature compressive strength and creep behavior of Si-Ti-C-O fiber-bonded ceramics

Fiber bonded silicon carbide ceramic materials provide cost-advantage over traditional ceramic matrix composites and require fewer processing steps. Despite their interest in extreme environment thermostructural applications no data on long term mechanical reliability other than static fatigue is available for them. We studied the high temperature compressive strength and creep behavior of a fiber bonded SiC material obtained by hot-pressing of Si Ti-C-O fibers. The deformation mechanism and onset of plasticity was evaluated and compared with other commercial SiC materials. Up to 1400 degrees C, plasticity is very limited and any macroscopic deformation proceeds by crack formation and damage propagation. A transient viscous creep stage is observed due to flow in the silica matrix and once steady state is established, a stress exponent n similar to 4 and an activation energy Q similar to 700 kJ mol(-1) are found. These results are consistent with previous data on creep of polymer derived SiC fibers and polycrystals.

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