ASTM C1793-15(2024) PDF

SIGNIFICANCE AND USE 4.1 Composite materials consist by definition of a reinforcement phase in a matrix phase. In addition, ceramic matrix composites (CMCs) often contain measurable porosity which interacts with the reinforcement and matrix. And SiC-SiC composites often use a fiber interface coating which has an important mechanical function. The composition and structure of these different constituents in the CMC are commonly tailored for a specific application with detailed performance requirements. The tailoring involves the selection of the reinforcement fibers (composition, properties, morphology, etc.), the matrix (composition, properties, and morphology), the composite structure (component fractions, reinforcement architecture, interface coatings, porosity structure, microstructure, etc.), and the fabrication conditions (forming, assembly, forming, densification, finishing, etc.). The final engineering properties (physical, mechanical, thermal, electrical, etc.) can be tailored across a broad range with major directional anisotropy in the properties. 4.2 Specifications for specific CMC components covering materials, material processing, and fabrication procedures are developed to provide a basis for fabricating reproducible and reliable structures. Designer/users/producers have to write CMC specifications for specific applications with well-defined composition, structure, properties and processing requirements. But with the extensive breadth of selection in composition, structure, and properties in CMCs, it is virtually impossible to write a "generic" CMC specification applicable to any and all CMC applications that has the same type of structure and details of the commonly-used specifications for metal alloys. This guide is written to assist the designer/user/producer in developing a comprehensive and detailed material specification for a specific CMC application/component with a specific focus on nuclear applications. 4.3 The purpose of this guide is to provide guidance o... SCOPE 1.1 This document is a guide to preparing material specifications for silicon carbide fiber/silicon carbide matrix (SiC-SiC) composite structures (flat plates, rectangular bars, round rods, and tubes) manufactured specifically for structural components and for fuel cladding in nuclear reactor core applications. The SiC-SiC composites consist of silicon carbide fibers in a silicon carbide matrix produced by liquid infiltration/pyrolysis and/or by chemical vapor infiltration. 1.2 This guide provides direction and guidance for the development of a material specification for a specific SiC-SiC composite component or product for nuclear reactor applications. The guide considers composite constituents and structure, physical and chemical properties, mechanical properties, thermal properties, performance durability, methods of testing, materials and fabrication processing, and quality assurance. The SiC-SiC composite materials considered here would be suitable for nuclear reactor core applications where neutron irradiation-induced damage and dimensional changes are significant design considerations. (1-8)2 1.3 The component material specification is to be developed by the designer/purchaser/user. The designer/purchaser/user shall define and specify in detail any and all application-specific requirements for design, manufacturing, performance, and quality assurance of the ceramic composite component. Additional specification items for a specific component, beyond those listed in this guide, may be required based on intended use, such as geometric tolerances, permeability, bonding, sealing, attachment, and system integration. 1.4 This guide is specifically focused on SiC-SiC composite components and structures with flat plate, solid rectangular bar, solid round rod, and tubular geometries. 1.5 This guide may also be applicable to the development of specifications for SiC-SiC composites used for other structural applic...