Comparison of the creep and creep rupture performance of two HIPed silicon nitride ceramics

Journal Article · Tue Mar 01 04:00:00 EST 1994 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb05345.x· OSTI ID:7046432

Ferber, M K; Jenkins, M G; Nolan, T A ^[1]; Yeckley, R L ^[2]

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1. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.
2. Norton Co., Northboro, MA (United States)

Measurements of the tensile creep and creep rupture behavior were used to evaluate the long-term mechanical reliability of a commercially available and a developmental hot isostatically pressed (HIPed) silicon nitride. Measurements were conducted at 1,260 and 1,370 C utilizing button-head tensile specimens. The stress and temperature sensitivities of the secondary creep rates were used to estimate the stress exponent and activation energy associated with the dominant creep mechanism. The stress and temperature dependencies of creep rupture life were determined by continuing individual creep tests to specimen failure. Creep deformation in both materials was associated with cavitation at multigrain junctions. Two-grain cavitation was also observed in the commercial material. Failure in both materials resulted from the evolution of an extensive damage zone. The failure times were uniquely related to the creep rates, suggesting that the zone growth was constrained by the bulk creep response. The fact that the creep and creep rupture behaviors of the developmental silicon nitride were significantly improved compared to those of the commercial material was attributed to the absence of cavitation along two-grain junctions in the developmental material.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7046432
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:3; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
CREEP
DEFORMATION
MECHANICAL PROPERTIES
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
SILICON COMPOUNDS
SILICON NITRIDES
TENSILE PROPERTIES