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Tensile Creep and Rupture of Silicon Nitride
Author(s) -
Krause Ralph F.,
Luecke William E.,
French Jonathan D.,
Hockey Bernard J.,
Wiederhorn Sheldon M.
Publication year - 1999
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.1151-2916.1999.tb01901.x
Subject(s) - creep , materials science , cavitation , silicon nitride , ultimate tensile strength , diffusion creep , composite material , stress (linguistics) , silicate , silicon , grain boundary , metallurgy , mechanics , microstructure , chemistry , linguistics , physics , philosophy , organic chemistry
We have characterized the tensile creep, rupture lifetime, and cavitation behavior of a commercial, gas‐pressure‐sintered silicon nitride in the temperature range 1150° to 1400°C and stress range 70 to 400 MPa. Individual creep curves generally show primary, secondary, and tertiary creep. The majority of the primary creep is not recoverable. The best representation of the data is one where the creep rate depends exponentially on stress, rather than on the traditional power law. This representation also removes the need to break the data into high and low stress regimes. Cavitation of the interstitial silicate phase accompanies creep under all conditions, and accounts for nearly all of the measured strain. These observations are consistent with a model where creep proceeds by the redistribution of silicate phase from cavitating interstitial pockets, accommodated by grain‐boundary sliding of silicon nitride.