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Modeling and Simulation of Ceramic Matrix Composite (CMC) Processes


OBJECTIVE: Develop computational methodology for modeling CMC fabrication processes to accelerate development and facilitate robust and efficient CMC manufacturing processes. DESCRIPTION: Integrated Computational Materials Science and Engineering (ICMSE) seeks to couple processing, microstructure, and performance via validated computational methods to accelerate materials development, transform the engineering design optimization process, and unify design and manufacturing. CMCs, possessing low density and high-temperature capability, are prime candidates for turbine engine hot-section components and advanced thermal protection systems. In order to be cost-effective alternatives to metal components, the development cycle time for CMCs must be reduced significantly. Modeling and simulation driven optimization of fabrication processes and manufacturing methods can reduce the cost and cycle time to implement CMCs in a variety of aerospace applications. This approach will also reduce the manufacturing trials required to optimize the process for producing specific components. Processes that are used to produce CMCs include one or more of the following, powder-slurry infiltration and densification, preceramic polymer infiltration and pyrolysis, chemical vapor infiltration, and liquid metal infiltration.[1-4] All of these methods rely on the infiltration of the desired matrix phase, or one or more precursors that react to form the desired matrix phase, into a fiber tow or cloth ply or preform architecture. Hence, the processes all rely on flow of gas, liquid, and/or solids though a porous media (fiber network and/or partially densified matrix), diffusion, chemical reactions, and densification, often repeated in multiple cycles, which can lead to residual stresses due to volume and temperature changes. A simulation-based approach will help achieve full densification of parts with minimal defects, dimensional distortions, and residual stress. In addition, silicon carbide-based CMCs require an environmental barrier coating (EBC), applied via plasma spray, physical vapor deposition, or slurry-based methods, to minimize volatilization of silicon hydroxides in combustion environments.[5] Key mechanisms for deposition of coatings to be included in a physics based modeling approach are transport kinetics, chemical reaction mechanisms, densification, volumetric and temperature changes, and residual stress effects. Physics-based computational tools and methodologies are needed to understand these processes, to provide predictive capabilities to model microstructure evolution during processing, and to identify effects of process parameters on microstructure and defect evolution in service. The offeror should conduct a detailed literature search to identify key issues associated with CMC matrix infiltration and/or coating processes. Selection of processes and microstructures to be modeled in Phase I should be representative of those being researched or developed by aircraft and turbine-engine manufacturers; therefore, teaming with a CMC manufacturer or end-user is highly recommended. The potential cost savings and cycle time reductions of the simulation-based approach should be validated in Phase II; one or more CMC components should be identified as test cases. Commercialization plans and qualification requirements should be established to offer these new techniques to the aerospace industry for evaluation and qualification in Phase III. Government Furnished Property (GFP) will not be provided for this topic. PHASE I: Demonstrate the feasibility of simulating either a commercially-relevant matrix infiltration process for CMCs or an EBC deposition process using a physics-based modeling approach that includes the ability to simulate all relevant physical phenomena. Demonstrate the ability to accurately represent infiltration or deposition and densification for simple geometries. PHASE II: Fully develop the manufacturing simulation tools developed in Phase I and validate the models and tools on typical CMC components. Working closely with aircraft or turbine engine manufacturers and CMC component manufacturers, demonstrate the cost and/or cycle time reduction claims. Demonstrate predictive capabilities to model microstructure evolution and effects of process parameters on defect populations. PHASE III: Process models developed should be made available to the turbine engine companies and CMC industry at large. CMCs are applicable to military engine hot-section components. They are also in development for commercial applications such as for power turbines and commercial aircraft engine components. REFERENCES: 1. W. Krenkel, ed., Ceramic Matrix Composites: Fiber-Reinforced Ceramics and their Applications, Wiley-VCH, Veinheim, Germany, 2008. 2. C.P. Deck, H.E. Khalifa, B. Sammuli, T. Hilsabeck, and C.A. Back,"Fabrication of SiC-SiC Composites for Fuel Cladding in Advanced Reactor Designs,"Prog. Nucl. Energy, 57 38-45 (2012). 3. J.S. Crompton, K.C. Koppenhoefer, S.P. Yushanov,"Simulation of Manufacturing Process of Ceramics Matrix Composites,"Ceram. Trans., Vol. 220, 37-46 (2010). 4. M. Erdal, S.I. Guceri, and S.C. Danforth,"Impregnation Molding of Particle-Filled Preceramic Polymer Infiltration into Fiber Preforms: Process Modeling,"J. Am. Ceram. Soc., 82, [8] 2017-2028 (1999). 5. K.N. Lee, D.S. Fox, and N.P. Bansal,"Rare-Earth Silicate Environmental Barrier Coatings for SiC/SiC Composites and Si3N4 Ceramics,"J. Eur. Ceram. Soc., 25 17051715 (2005).
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