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Compressive Creep and Creep Failure of 8Y 2 O 3 /3Al 2 O 3 ‐Doped Hot‐Pressed Silicon Nitride
Author(s) -
Crampon Jacques,
Duclos Richard,
Peni Fation,
Guicciardi Stefano,
Portu Goffredo
Publication year - 1997
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1997.tb02794.x
Subject(s) - creep , materials science , diffusion creep , cavitation , grain boundary sliding , composite material , grain boundary , activation energy , stress (linguistics) , atmospheric temperature range , silicon nitride , phase (matter) , grain boundary diffusion coefficient , thermodynamics , microstructure , chemistry , linguistics , physics , philosophy , layer (electronics) , organic chemistry
The compressive creep properties of hot‐pressed Si 3 N 4 8Y 2 O 3 —3Al 2 O 3 (wt%) have been investigated in the temperature range of 1543–1603 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 1573 K, in the stress range of 175–300 MPa, followed the MonkmanGrant relation, indicating that cavity growth was mainly controlled by the creep response of the material.