DYNAMIC FATIGUE TESTING OF CANDIDATE CERAMIC MATERIALS FOR TURBINE-ENGINES TO DETERMINE SLOW-CRACK-GROWTH PARAMETERS

The purpose of this study was to evaluate the mechanical strength and slow-crack-growth parameter values for two commercially available sili con nitrides, SN-88 and NT164, at three high-temperature conditions, W eibull analysis and dynamic fatigue slow-crack-growth parameters were used to characterize the material strength and resistance to slow crac k growth at high temperatures for Else in life prediction models. Alth ough both materials are commercially available Si3N4, their high-tempe rature behavior was found to be significantly different.