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Thermal shock resistance of ceramic matrix compositesThe experimental and analytical investigation of the thermal shock phenomena in ceramic matrix composites is detailed. The composite systems examined were oxide-based, consisting of an aluminosilicate matrix with either polycrystalline aluminosilicate or single crystal alumina fiber reinforcement. The program was divided into three technical tasks; baseline mechanical properties, thermal shock modeling, and thermal shock testing. The analytical investigation focused on the development of simple expressions for transient thermal stresses induced during thermal shock. The effect of various material parameters, including thermal conductivity, elastic modulus, and thermal expansion, were examined analytically for their effect on thermal shock performance. Using a simple maximum stress criteria for each constituent, it was observed that fiber fracture would occur only at the most extreme thermal shock conditions and that matrix fracture, splitting parallel to the reinforcing fiber, was to be expected for most practical cases. Thermal shock resistance for the two material systems was determined experimentally by subjecting plates to sudden changes in temperature on one surface while maintaining the opposite surface at a constant temperature. This temperature change was varied in severity (magnitude) and in number of shocks applied to a given sample. The results showed that for the most severe conditions examined that only surface matrix fracture was present with no observable fiber fracture. The impact of this damage on material performance was limited to the matrix dominated properties only. Specifically, compression strength was observed to decrease by as much as 50 percent from the measured baseline.
Document ID
19940009447
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Carper, D. M.
(General Electric Co. Cincinnati, OH, United States)
Nied, H. F.
(General Electric Co. Schenectady, NY., United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1993
Subject Category
Composite Materials
Report/Patent Number
NAS 1.26:189136
E-8070
NASA-CR-189136
Report Number: NAS 1.26:189136
Report Number: E-8070
Report Number: NASA-CR-189136
Accession Number
94N13920
Funding Number(s)
PROJECT: RTOP 510-01-50
CONTRACT_GRANT: NAS3-25640
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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