Evolution of stress failure resulting from high-temperature stress-corrosion cracking in a hot isostatically pressed silicon nitride

Journal Article · Tue Aug 01 04:00:00 EDT 1995 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1995.tb08625.x· OSTI ID:106007

Wereszczak, A A; Ferber, M K; Kirkland, T P; More, K L ^[1]; Foley, M R; Yeckley, R L ^[2]

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1. Oak Ridge National Lab., TN (United States). High Temperature Materials Lab.
2. Saint-Gobain/Norton Industrial Ceramics Corporation, Northboro, MA (United States)

Stress-corrosion cracking in a commercially available, hot isostatically pressed (HIPed), yttria-fluxed, silicon nitride was the prevalent mode of failure in specimens creep-ruptured at 1,370 C. High-temperature diffusional processes associated with oxygen were responsible for the creation of an advancing stress-corrosion front that had formed at the specimen surface and advanced radially inward. The volume of material in the wake of the stress-corrosion front possessed a high concentration of lenticular cavities at two-grain boundaries, a high concentration of multigrain junction cavities, and large amorphous ``pockets`` in other multigrain junctions that were abnormally rich in oxygen and yttrium. The combination of tensile stress and the high concentration of cavities in the near-surface volume of the material resulted in microcrack coalescence or the formation of a planar, stress-corrosion crack. The concurrent growth of the stress-corrosion front and crack during the tensile creep-rupture tests ultimately led to stress-induced failure.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 106007
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 8 Vol. 78; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
CAVITIES
CRACK PROPAGATION
CRACKS
CREEP
DIFFUSION
FRACTURE PROPERTIES
GAS TURBINES
GRAIN BOUNDARIES
MATERIALS
SILICON NITRIDES
STRESS CORROSION
STRESSES
TENSILE PROPERTIES
YTTRIUM OXIDES