| Frequency and Hold-Time Effects on Durability of Melt-Infiltrated SiC/SiC (Preprint) |
Jul 2011 |
11 pages |
| Authors:
R John; G Ojard; R Miller; Y Gowayed; G Morscher; U Santhosh; J Ahmad; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIR METALS CERAMICS AND NONDESTRUCTIVE EVALUATION DIV/METALS BRANCH
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 | With the growing interest in ceramic matrix composites for multiple applications, the response of the material to service conditions needs to be understood. A range of durability assessment was undertaken on Melt Infiltrated (MI) SiC/SiC Ceramic Matrix Composite. MI SiC/SiC was tested under 30 Hz fatigue, 1 Hz fatigue, dwell fatigue (2 hour hold cycle) and creep loading. The applied stresses ranged from the micro-cracking initiation point to well above ... |
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| Accumulation of Time-Dependent Strain during Dwell-Fatigue Experiments of iBN-Sylramic Melt Infiltrated SiC/SiC Composites with and without Holes (Preprint) |
Jul 2011 |
26 pages |
| Authors:
R John; G Ojard; R Miller; Y Gowayed; J Chen; G Morscher; U Santhosh; J Ahmad; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIR METALS CERAMICS AND NONDESTRUCTIVE EVALUATION DIV/METALS BRANCH
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| Accumulation of time-dependent strain during dwell-fatigue experiments of iBN-Sylramic Melt Infiltrated SiC/SiC composites is investigated. A 2-hour load cycle is repeated for specimens without holes and specimens with a central hole under the following conditions: i) a stress ratio of 0.05, ii) various stress levels, iii) 815 deg C and 1204 deg C, iv) different times up to 600 hours, and v) different hole diameters. An increase in the accumulation ... |
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| Thermocouple Interactions During Testing of Melt Infiltrated Ceramic Matrix Composites (Postprint) |
Jan-2008 |
12 pages |
| Authors:
R John; G Ojard; G Morscher; Y Gowayed; U Santhosh; J Ahmad; R Miller; PRATT AND WHITNEY AIRCRAFT GROUP EAST HARTFORD CT
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| As high performance ceramic matrix composite systems, such as Melt Infiltrated (MI) SiC/SiC, are being considered for advanced gas turbine engine applications, the characterization of the material becomes more important. A series of test were conducted where Pt and Ni sheathed Pt thermocouples were used to monitor temperature for short and long duration fast fracture, fatigue and creep tests. While it is known that Si forms eutectics with Pt and ... |
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| Through Thickness Modulus (E33) of Ceramic Matrix Composites: Mechanical Test Method Confirmation (Preprint) |
Jan-2008 |
7 pages |
| Authors:
R John; G Ojard; Y Gowayed; U Santhosh; R Miller; T Barnett; A Calomino; J Ahmaad; PRATT AND WHITNEY EAST HARTFORD CT
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| Considering the interest in and challenges of using ceramic matrix composites, a full understanding of the physical properties is needed to continue to move the technology forward. A property of interest to the design process is the through thickness modulus of the composite and most high performance CMC material systems are produced extremely thin hindering generation of test specimens that can easily be instrumented and tested in the through-thickness direction. ... |
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| The Effect of Holes on the Residual Strength of SiC/SiC Ceramic Composites (Preprint) |
Nov 2007 |
10 pages |
| Authors:
G Ojard; R Miller; Y Gowayed; U Santhosh; J Ahmaad; R John; PRATT AND WHITNEY EAST HARTFORD CT
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| Continued interest in ceramic matrix composites for the use in high temperature applications necessitates a comprehensive understanding of the effect of time-dependent loading in various environments on the material mechanical response. This understanding has to include the effect of structural features, such as holes, on the material performance. In this work, residual strength tests were conducted for samples with 2.286, and 4.572 mm diameter holes, located at the center of ... |
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