Dynamic Fatigue Testing of Candidate Ceramic Materials for Turbine Engines to Determine Slow-Crack-Growth Parameters

Osborne, Nora; Graves, George; Ferber, M. K.

doi:10.1115/95-gt-235

Cited by 2 publications

(3 citation statements)

References 2 publications

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“…As a consequence, the a consequence of the ytterbium-silicon-oxynitride grain boundary phase undergoing some softening. This phenomenon has been reported for this material in flexure loading at 1350°C (Osborne and Graves, 1995).…”

Section: Youne's Modulus Of Si3n4 and Sicsupporting

confidence: 83%

“…Silicon nitride (Si3s14) and silicon carbide (SiC) ceramics are leading candidates for use as structural components, e.g., nozzles and combustor tiles (Parthasarathy et at, 1995), in advanced industrial gas turbine engines. The utilization of Si3Is14 or SiC over more traditional alloys offers several advantages such as higher temperature capability (and an associated increased operating efficiency), reduced weight and inertia effects, and the potential design and use of non-cooled components.…”

Section: Introductionmentioning

confidence: 99%

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Creep Performance of Candidate SiC and Si3N4 Materials for Land-Based, Gas Turbine Engine Components

Wereszczak

Kirkland

1996

Volume 5: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation;

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The tensile creep-rupture performance of a commercially available gas pressure sintered silicon nitride (Si3N4) and a sintered silicon carbide (SiC) is examined at 1038, 1150, and 1350°C. These two ceramic materials are candidates for nozzles and combustor tiles that are to be retrofitted in land-based gas turbine engines, and interest exists to investigate their high temperature mechanical performance over service-times up to, and in excess of, 10000 hours (≈ 14 months). To achieve lifetimes approaching 10000 hours for the candidate Si3N4 ceramic, it was found (or it was estimated based on ongoing test data) that a static tensile stress of 300 MPa at 1038 and 1150°C, and a stress of 125 MPa at 1350°C cannot be exceeded. For the SiC ceramic, it was estimated from ongoing test data that a static tensile stress of 300 MPa at 1038°C, 250 MPa at 1150°C, and 180 MPa at 1350°C cannot be exceeded. The creep-stress exponents for this Si3N4 were determined to be 33, 17, and 8 for 1038, 1150, and 1350°C, respectively. The fatigue-stress exponents for the Si3N4 were found to be equivalent to the creep exponents, suggesting that the fatigue mechanism that ultimately causes fracture is controlled and related to the creep mechanisms. Little success was experienced at generating failures in the SiC after several decades of time through exposure to appropriate tensile stress; it was typically observed that if failure did not occur on loading, then the SiC specimens most often did not creep-rupture. However, creep-stress exponents for the SiC were determined to be 57, 27, and 11 for 1038, 1150, and 1350°C, respectively. For SiC, the fatigue-stress exponents did not correlate as well with creep-stress exponents. Failures that occurred in the SiC were a result of slow crack growth that initiated from the specimen’s surface.

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Section: Youne's Modulus Of Si3n4 and Sicsupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Creep Performance of Candidate SiC and Si3N4 Materials for Land-Based, Gas Turbine Engine Components

Wereszczak

Kirkland

1996

Volume 5: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation;

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“…Previous references to the creep and rupture of the silicon nitride of this study can be found in the literature. [15][16][17][18][19][20][21][22][23] The data from this study are part of a much larger engineering study of the suitability of monolithic silicon nitride for gas turbine engine applications. 24…”

Section: Introductionmentioning

confidence: 99%

Tensile Creep and Rupture of Silicon Nitride

Krause

Luecke

French

et al. 1999

Journal of the American Ceramic Society

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We have characterized the tensile creep, rupture lifetime, and cavitation behavior of a commercial, gas-pressuresintered 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.

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Dynamic Fatigue Testing of Candidate Ceramic Materials for Turbine Engines to Determine Slow-Crack-Growth Parameters

Cited by 2 publications

References 2 publications

Creep Performance of Candidate SiC and Si3N4 Materials for Land-Based, Gas Turbine Engine Components

Creep Performance of Candidate SiC and Si3N4 Materials for Land-Based, Gas Turbine Engine Components

Tensile Creep and Rupture of Silicon Nitride

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