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Cavitation Creep in the Next Generation Silicon Nitride

Published

Author(s)

F Lofaj, Sheldon M. Wiederhorn, Gabrielle G. Long, P R. Jemian, M Ferber

Abstract

X-ray scattering (A-USAXS). Failure strains were around 0.5 %. The creep resistance of this grade was found to be up to two orders of magnitude better than that of other silicon nitrides. The corresponding stress exponents were higher than 6. Creep damage consists of multigrain junction cavities. Strain rate data fit the theoretical predictionaccording to the cavitation creep model of Luecke and Wiederhorn which is based on a dilatation of the secondary phase pockets. Evolution of the pockets containing secondary phases was confirmed by A - USAXS. High creep resistance in the current material is attributed to the suppression of cavitation via restriction of the redistribution of the secondary phases using crystalline secondary phases and residual glass with higher effective viscosity. High creep resistance seems to result from new type of sintering additives containing Lu. Lutetium-based secondary phases are essential for the next generation of silicon nitrides with the operating temperatures up to 1500 C.
Citation
Ceramics Material and Components for Engines

Keywords

cavitation, creep, effective viscosity, silicon nitride

Citation

Lofaj, F. , Wiederhorn, S. , Long, G. , Jemian, P. and Ferber, M. (2021), Cavitation Creep in the Next Generation Silicon Nitride, Ceramics Material and Components for Engines (Accessed May 28, 2024)

Issues

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Created October 12, 2021