Flexural stress rupture and creep of commercial silicon nitrides

Technical Report · Sun Dec 01 04:00:00 EST 1991

OSTI ID:5718654

Sanders, W A ^[1]; Groseclose, L E ^[2]

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1. Analex Corp., Brook Park, OH (United States)
2. General Motors Corp., Indianapolis, IN (United States). Allison Gas Turbine Div.

Four commercial Si{sub 3}N{sub 4} compositions were compared with regard to flexural stress rupture and creep in ambient air as a function of temperature from 1100 to 1400{degrees}C and stress from 200 to 350 MPa. One Si{sub 3}N{sub 4}, SN252, was found to be more resistant to time-dependent deformation in both stepped-temperature stress rupture tests and creep tests than a very similar Si{sub 3}N{sub 4} composition and two other dissimilar Si{sub 3}N{sub 4} compositions. Materials were compared on the bases of percent final strains, creep rates, and post-test microscope examinations. The latter revealed tensile face transverse cracking, and slow crack growth. The superior behavior of the SN252 Si{sub 3}N{sub 4} was related to its microstructure.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• OSTI ID: 5718654
• Report Number(s): DOE/NASA-5776-1; NASA/CR--189074; ON: DE92008463; CNN: NAS3-25776
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330103 -- Internal Combustion Engines-- Turbine
36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
CRACK PROPAGATION
CREEP
CRYSTAL STRUCTURE
ENGINES
FAILURES
FLEXURAL STRENGTH
FRACTURE PROPERTIES
GAS TURBINE ENGINES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
MECHANICAL PROPERTIES
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
RUPTURES
SILICON COMPOUNDS
SILICON NITRIDES
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K