Compressive creep and creep failure of 8Y{sub 2}O{sub 3}/3Al{sub 2}O{sub 3}-doped hot-pressed silicon nitride

Journal Article · Wed Jan 01 00:00:00 EST 1997 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1997.tb02794.x· OSTI ID:455158

Crampon, J; Duclos, R ^[1]; Peni, F; Guicciardi, S; Portu, G De ^[2]

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1. Univ. des Sciences et Technologies de Lille, Villeneuve-d`Ascq (France)
2. National Research Council, Faenza (Italy). Research Inst. for Ceramic Technology

The compressive creep properties of hot-pressed Si{sub 3}N{sub 4}-8Y{sub 2}O{sub 3}-3Al{sub 2}O{sub 3} (wt%) have been investigated in the temperature range of 1,543--1,603 K in air. The stress exponent, n, of the power creep law was determined to be 1.5, and the activation energy was determined to be 650 kJ/mol. Transmission electron microscopy observations showed that grain-boundary sliding occurred with cavitation formation in the grain-boundary glassy phase. The quasi-steady-state creep results were consistent with that of the diffusion-controlled solution-diffusion-precipitation creep mechanism, and the distinguished failure mechanism was cavitation creep damage controlled by the viscosity of the boundary glassy phase. The compressive creep failure time, obtained at 1,573 K, in the stress range of 175--300 MPa, followed the Monkman-Grant relation, indicating that cavity growth was mainly controlled by the creep response of the material.

• Sponsoring Organization: USDOE
• OSTI ID: 455158
• Journal Information: Journal of the American Ceramic Society, Vol. 80, Issue 1; Other Information: PBD: Jan 1997
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CREEP
YTTRIUM OXIDES
ALUMINIUM OXIDES
SILICON NITRIDES
HOT PRESSING
GRAIN BOUNDARIES
ACTIVATION ENERGY
DIFFUSION
BULK DENSITY
EXPERIMENTAL DATA