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Creep and Stress Rupture Behavior of an Advanced Silicon Nitride: Part I, Experimental Observations
Author(s) -
Me Mamballykalathil N.,
Fang Ho T.,
Wu David C.,
Jenkins Michael G.,
Ferber Mattison K.,
More Karren L.,
Hubbard Camden R.,
Nolan Theodore A.
Publication year - 1994
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.1151-2916.1994.tb05395.x
Subject(s) - creep , fractography , materials science , cavitation , silicon nitride , composite material , stress (linguistics) , scanning electron microscope , atmospheric temperature range , metallurgy , silicon , forensic engineering , thermodynamics , philosophy , engineering , linguistics , physics
Cylindrical buttuohead specimens of an advanced silicon nitride were tested in uniaxial tension at temperatures between 1422 and 1673 K. In the range 1477 to 1673 K, creep deformation was reliably measured using high‐temperature contact probe extensometry. Extensive scanning and transmission electron microscopy has revealed the formation of lenticular cavities at two‐grain junctions at all temperatures (1422–1673 K) and extensive triple‐junction cavitation occurring at the higher temperatures (1644–1673 K). Cavitation is believed to be part of the net creep process. The stress rupture data show stratification of the Monkman–Grant lines with respect to temperature. Failure strain increased with increase in rupture time or temperature, or decrease in stress. Fractography showed that final failure occurred by subcritical crack growth in all specimens.