Thermocouple Interactions During Testing of Melt Infiltrated Ceramic Matrix Composites (Postprint)
PRATT AND WHITNEY AIRCRAFT GROUP EAST HARTFORD CT
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As high performance ceramic matrix composite systems, such as Melt Infiltrated MI SiCSiC, are being considered for advanced gas turbine engine applications, the characterization of the material becomes more important. A series of test were conducted where Pt and Ni sheathed Pt thermocouples were used to monitor temperature for short and long duration fast fracture, fatigue and creep tests. While it is known that Si forms eutectics with Pt and Ni, this was initially not considered an issue. But since MI SiCSiC composite achieves much of its performance from the infiltrated phase of Silicon for high conductivity and low porosity, it was felt that further study of possible interactions of the Si phase has to be considered. Post-test real-time X-ray inspection of the mechanical time-dependent and time-independent testing revealed that the extent of alloying into the sample was greater than anticipated an in some cases extended throughout the entire gage section of the tensile bars. It was concluded that the interactions were limited to the Si Phase of the material and that there was no difference between samples affected by alloying versus those that did not.
- Ceramics, Refractories and Glass
- Properties of Metals and Alloys