Evaluation and Constitutive Modeling of Unidirectional Sic/Sic Composites with Engineered Sic Fiber Coatings Subjected to Neutron Irradiation

41224 Hyper-Therm High Temperature Composites, Inc. Continuous silicon carbide (SiC) fiber-reinforced SiC-matrix composites (SiC/SiC) produced by chemical vapor infiltration (CVI) have been identified as a promising material for fusion energy applications. Currently available fiber coatings such as pyrolytic carbon and boron nitride have demonstrated the desired mechanical characteristics required to promote high composite strength and toughness, however the utility of these materials are severely limited by their susceptibility to mechanical degradation when exposed to neutron irradiation. This limitation is due in part to the microstructural instability of the fiber coating as a result of radiation exposure. The objective of this project is to investigate the characteristic behavior of model SiC/SiC composites subjected to neutron radiation conditioning. Test samples for three matrix composite plate variants will be produced and evaluated to determine critical mechanical properties before and after neutron irradiation. Commercial Applications and Other Benefits as described by the awardee: SiC-matrix composites are an enabling class of materials for first wall plasma containment, liner and divertor components in fusion energy systems; stationary turbine and power generation components, radiant burner and heat exchanger tubes; and for a variety of thermostructural applications in aerospace propulsion combustors and nozzles, hypersonic airframe thermal protection systems, and spacecraft re-entry heatshields.