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Tension-compression testing of hip-treated sintered SiC for gas turbine applications at temperatures between 1400 deg C and 1600 deg C

 
: Westerheide, R.; Hollstein, T.; Schwetz, K.A.

6th International Symposium on Ceramic Materials and Components for Engines 1997
S.l., 1997
pp.253-258 : Ill., Lit.
International Symposium on Ceramic Materials and Components for Engines <6, 1997>
English
Conference Paper
Fraunhofer IWM ()

Abstract
The increasing material temperatures of gas turbine components have the consequences that ceramic materials are taken more and more into account as construction materials. Typical components are turbine blades, nozzles, inlet liners, heat exchangers or combustion components. For their design the material data at operating temperatures have to be known. The most important data are strength, tensile creep and fatigue strength, and the gas corrosion behaviour, which are presented here for a sintered silicon carbide and for temperatures up to 1550 deg C. With slightly modified commercial water cooled hydraulic grips for tension-compression loading a maximum specimen temperature of 1550 deg C could be reached. The development of grips with hot elements have reduced the temperature gradient between the clamping and testing areas of the specimen. With this system specimen temperatures up to 1600 deg C can be reached over a measuring length of 25 mm. Due to the reduced thermal gradient also sh orter specimens can be used. The tensile creep experiments with the silicon carbide tested here show, that a maximum operating temperature for long term applications is limited to about 1500 deg C. Significant creep deformation at 20OMPa occurs above 1500 deg C. The minimum creep rate can be described by a power law, and the activation energy by an exponential law as far as corrosion can be neglected. After cyclic tension-compression loading at 1Hz over 100hrs slightly reduced strength values are detected. The fractographic investigations of the specimens have shown that the strength degradation is more a result of gas corrosion than a result of microstructural fatigue at temperatures >= 1 550 deg C.

: http://publica.fraunhofer.de/documents/PX-36192.html