Effective Nondestructive Detection and Quantification of Defects and Damage in Ceramic Matrix Composites (CMCs)

ABSTRACT: The objective of this project is to develop nondestructive evaluation technology to locate and characterize defects and damage in ceramic matrix composite material with sufficient quantification to be usable in material performance models. The Evisive microwave interferometry technique has been successfully applied to nondestructive examination and determination of density and porosity in S-200 ceramic matrix composite (CMC) material. In Phase I of this project, delaminations and macro-pores in an S-200 part were detected, sized and located in depth using the Evisive microwave technique and validated with micro-focus x-ray computed tomography. 20 simultaneous, discrete depth images, and 3D data file output were demonstrated. In Phase II this technology will be used to quantify characteristics of known defects, which will be destructively analyzed and used to validate models for prediction of material performance and live prediction. Inspection speed, data output and quantitative validation will be suitable for use in material property prediction for parts. Evisive scan microwave interferometry requires no contact and no coupling media, and supports real time evaluation. The project will leverage these characteristics to provide practical testing strategies for manufacturing and in-service environments. The project is anticipated to extend methodology applicable to manufacturing of S-200 material to advanced materials. BENEFIT: CMC materials offer higher temperature capability, reduced weight, and improved durability compared to conventional materials. They are potential suitable for a variety of high temperature structural applications in turbine engines and elsewhere. In order to apply the material, it is necessary to develop models which are able to predict material performance and degradation associated with deviations in design properties; and to predict material longevity. Evisive Scan microwave interferometry has been demonstrated to be effective in nondestructive testing of S-200 and similar CMC material. Development of quantitative NDE measurements which are sufficiently precise and repeatable to support modeling of the material properties will enable prediction of useful life, and enable use of the material in many novel and highly effective applications. Replicating these NDE methods in the in-service environment will enable condition monitoring and effective application of the material. Effective quantification of manufacturing irregularities and in-service degradation will facilitate migration of the material into service applications, as well as supporting advancement of the CMC material itself. Efficient NDE process and manufacturing quality control will reduce manufacturing cost and further enable migration of the CMC materials into service applications. This proposal includes letters from Alliant Techsystems Inc. (ATK), COI Ceramics, Inc. (COIC) and Pratt & Whitney, expressing support for further development and application of the Evisive microwave NDE technology for quantitative NDE of CMCs. Letters expressing support for performance of the project from COIC, Penn State Center for Innovative Sintered Products and Materials Research & Design, Inc. (MR & D) are also included. Copies of the ATK and Pratt & Whitney letters of under SBIR Topic AF07-105 are included, as these indicate intended incorporation into their manufacturing processes and potentially utilize the technique as a quality assurance tool in acceptance of manufactured CMC parts. As identified in the letters of support, it is anticipated that the technology will be beneficially expanded to support in-service condition monitoring, and operating cycle improvements.