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Thermomechanical Performance of Si-Ti-C-O and Sintered SiC Fiber-Bonded Ceramics at High Temperatures

Journal Article · · International Journal of Applied Ceramic Technology

The stress-temperature-lifetime response of Si-Ti-C-O fiber-bonded ceramic (Tyrannohex ) and sintered SiC fiber-bonded ceramic (SA-Tyrannohex ) materials were investigated in air from 500 to 1150 C and 500 to 1400 C, respectively. The apparent threshold stress of Si-Ti-C-O fiber-bonded ceramic was about 175 MPa in the 500-1150 C temperature range. When the applied stress of the sintered SiC fiber-bonded ceramic was below an apparent threshold stress (e.g., ~225MPa) for tests conducted 1150 C, no failures were observed for lifetimes up to 1000h. In the case of sintered SiC fiber-bonded ceramic, at the temperature of 1300 C, the apparent threshold stress decreased to 175 MPa. The decrease in strength seemed to be caused by grain growth which was confirmed from the SEM fractography. Both fiber-bonded ceramics exhibited much higher durability than a commercial SiC/SiC composite at temperatures above 500 C. In addition, results suggested that the sintered SiC fiber-bonded ceramic (SA-Tyrannohex) is more stable than a Hi-Nicalon/MI SiC composite with BN/SiC fiber coating at temperatures above 1300 C.

Research Organization:
Oak Ridge National Laboratory (ORNL)
Sponsoring Organization:
ORNL work for others
DOE Contract Number:
AC05-00OR22725
OSTI ID:
1024238
Journal Information:
International Journal of Applied Ceramic Technology, Journal Name: International Journal of Applied Ceramic Technology Journal Issue: 2 Vol. 8; ISSN 1546-542X
Country of Publication:
United States
Language:
English