Evaluation of ceramic matrix composites by thermal diffusivity imaging.
Because of the complex structural design and multiple processing steps, ceramic matrix composites (CMCs) typically contain a variety of flaws distributed throughout the volume. These flaws need to be detected and characterized because they are detrimental to CMC material properties. Thermal diffusivity imaging is a nondestructive evaluation method that can quantitatively determine the thermal property of a CMC component. Thermal diffusivity is an intrinsic material property that not only depends on the material constituents but also on the micro- and macrostructure of the CMC component. This paper investigates fundamental theories for thermal diffusivity measurement using pulsed thermal imaging from two- and one-sided setups. The variation of thermal diffusivity is examined for two types of flaws, voids and cracks, that are commonly present within CMCs. The sensitivity of thermal imaging to detect small and large flaws is analyzed and evaluated with measured thermal diffusivity data. In addition, analysis of fracture theories for the mechanical and thermal properties of materials with distributed microcracks has identified that thermal diffusivity may be used to determine the degradation of mechanical properties and, therefore, to predict the remaining life of a CMC component. Preliminary results for correlating thermal and mechanical properties are discussed.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- EE
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 939068
- Report Number(s):
- ANL/NE/JA-57195; TRN: US200821%%137
- Journal Information:
- Int. J. Appl. Ceram. Technol., Vol. 4, Issue 1 ; 2007
- Country of Publication:
- United States
- Language:
- ENGLISH
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