ASTM C1793-15(2024)
(Guide)Standard Guide for Development of Specifications for Fiber Reinforced Silicon Carbide-Silicon Carbide Composite Structures for Nuclear Applications
Standard Guide for Development of Specifications for Fiber Reinforced Silicon Carbide-Silicon Carbide Composite Structures for Nuclear Applications
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...
General Information
- Status
- Published
- Publication Date
- 31-Dec-2023
- Technical Committee
- C28 - Advanced Ceramics
- Drafting Committee
- C28.07 - Ceramic Matrix Composites
Relations
- Effective Date
- 01-Jan-2024
- Effective Date
- 01-Jan-2024
- Effective Date
- 01-Jan-2024
Overview
ASTM C1793-15(2024), "Standard Guide for Development of Specifications for Fiber Reinforced Silicon Carbide-Silicon Carbide Composite Structures for Nuclear Applications," provides a comprehensive framework for drafting specifications for silicon carbide (SiC) fiber-reinforced SiC matrix composite components. Developed by ASTM International, this standard focuses on SiC-SiC composites used in nuclear reactor core structures, including flat plates, bars, rods, and tubular forms.
SiC-SiC composites are favored for nuclear settings due to their exceptional thermal stability, oxidation resistance, radiation tolerance, and mechanical robustness. The guide details how to define and document requirements for materials, processing, and quality control to ensure the reliable, repeatable production of these advanced composites.
Key Topics
Composite Constituents:
- SiC-SiC composites consist of silicon carbide fibers embedded within a silicon carbide matrix.
- The selection of fiber type, matrix structure, fiber architecture, and interface coating is tailored based on performance demands.
Specification Development:
- Guides the creation of detailed material specifications for SiC-SiC composites with nuclear applications in mind.
- Emphasizes the importance of defining composition, structure, properties, and processing requirements to match the intended use.
Physical and Mechanical Properties:
- Composites are engineered to specific requirements of density, porosity, thermal expansion, conductivity, electrical resistivity, and mechanical strength.
- Properties may be tailored with significant anisotropy, depending on fiber architecture and intended directionality of use.
Quality Assurance and Testing:
- Recommends methods for testing chemical purity, mechanical strength, and physical characteristics using ASTM standards.
- Includes direction on statistical sampling, quality assurance, and traceability for each production batch.
Nuclear Application Specifics:
- Outlines special considerations for controlling impurities to minimize neutron absorption and avoid undesired chemical reactivity.
- Specifications must address requirements unique to nuclear service, such as radiation-induced dimensional changes and elevated temperature performance.
Applications
Nuclear Reactor Core Structures:
- SiC-SiC composites are primarily used in structural components and fuel cladding for nuclear reactors, where performance under irradiation and high temperature is critical.
- Their low neutron absorption and high radiation tolerance make them suitable for advanced reactor designs.
Other Structural Uses:
- While focused on nuclear applications, the guide also supports the development of specifications for SiC-SiC composites in other high-temperature or corrosive environments, provided nuclear-specific factors are modified as required.
Component Geometry:
- Applicable to flat plates, solid bars (rectangular and round), and tubes; these shapes are common in nuclear reactor core construction and broader engineering applications.
Related Standards
To ensure consistency and accuracy in specification and testing, ASTM C1793-15(2024) references several related standards, including:
- ASTM C242: Terminology of Ceramic Whitewares and Related Products
- ASTM C559, C838, C1039: Testing of density and porosity in ceramic materials
- ASTM C1470, E228, E289: Methods for measuring thermal expansion and conductivity
- ASTM C1233: Determining equivalent boron content, important for nuclear-grade materials
- ASTM D3878, D4018: Terminology and properties for composite materials and fibers
- ASME B46.1: Surface texture (surface roughness) assessment
Consistent application of these standards ensures reliable characterization and repeatable quality for SiC-SiC composites used in demanding service environments such as nuclear reactors.
Keywords: ASTM C1793, SiC-SiC composites, silicon carbide fiber, ceramic matrix composites, nuclear reactor materials, material specification guide, mechanical testing ASTM, composite properties, fiber architecture, testing standards for composites, nuclear applications, ASTM standards for ceramics.
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Frequently Asked Questions
ASTM C1793-15(2024) is a guide published by ASTM International. Its full title is "Standard Guide for Development of Specifications for Fiber Reinforced Silicon Carbide-Silicon Carbide Composite Structures for Nuclear Applications". This standard covers: 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...
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...
ASTM C1793-15(2024) is classified under the following ICS (International Classification for Standards) categories: 83.120 - Reinforced plastics. The ICS classification helps identify the subject area and facilitates finding related standards.
ASTM C1793-15(2024) has the following relationships with other standards: It is inter standard links to ASTM C1793-15, ASTM C1835-16(2023), ASTM C1869-18(2023). Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ASTM C1793-15(2024) is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C1793 − 15 (Reapproved 2024)
Standard Guide for
Development of Specifications for Fiber Reinforced Silicon
Carbide-Silicon Carbide Composite Structures for Nuclear
Applications
This standard is issued under the fixed designation C1793; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.5 This guide may also be applicable to the development of
specifications for SiC-SiC composites used for other structural
1.1 This document is a guide to preparing material specifi-
applications, discounting the nuclear-specific chemical purity
cations for silicon carbide fiber/silicon carbide matrix (SiC-
and irradiation behavior factors.
SiC) composite structures (flat plates, rectangular bars, round
rods, and tubes) manufactured specifically for structural com- 1.6 Units—The values stated in SI units are to be regarded
ponents and for fuel cladding in nuclear reactor core applica- as standard. No other units of measurement are included in this
tions. The SiC-SiC composites consist of silicon carbide fibers standard.
in a silicon carbide matrix produced by liquid infiltration/
1.7 This standard does not purport to address all of the
pyrolysis and/or by chemical vapor infiltration.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
1.2 This guide provides direction and guidance for the
priate safety, health, and environmental practices and deter-
development of a material specification for a specific SiC-SiC
mine the applicability of regulatory limitations prior to use.
composite component or product for nuclear reactor applica-
1.8 This international standard was developed in accor-
tions. The guide considers composite constituents and
dance with internationally recognized principles on standard-
structure, physical and chemical properties, mechanical
ization established in the Decision on Principles for the
properties, thermal properties, performance durability, methods
Development of International Standards, Guides and Recom-
of testing, materials and fabrication processing, and quality
mendations issued by the World Trade Organization Technical
assurance. The SiC-SiC composite materials considered here
Barriers to Trade (TBT) Committee.
would be suitable for nuclear reactor core applications where
neutron irradiation-induced damage and dimensional changes
2 2. Referenced Documents
are significant design considerations. (1-8)
2.1 ASTM Standards:
1.3 The component material specification is to be developed
C242 Terminology of Ceramic Whitewares and Related
by the designer/purchaser/user. The designer/purchaser/user
Products
shall define and specify in detail any and all application-
C559 Test Method for Bulk Density by Physical Measure-
specific requirements for design, manufacturing, performance,
ments of Manufactured Carbon and Graphite Articles
and quality assurance of the ceramic composite component.
C577 Test Method for Permeability of Refractories
Additional specification items for a specific component, be-
C611 Test Method for Electrical Resistivity of Manufactured
yond those listed in this guide, may be required based on
Carbon and Graphite Articles at Room Temperature
intended use, such as geometric tolerances, permeability,
C625 Practice for Reporting Irradiation Results on Graphite
bonding, sealing, attachment, and system integration.
C714 Guide for Thermal Diffusivity of Carbon and Graphite
1.4 This guide is specifically focused on SiC-SiC composite
by Thermal Pulse Method
components and structures with flat plate, solid rectangular bar,
C769 Test Method for Sonic Velocity in Manufactured
solid round rod, and tubular geometries.
Carbon and Graphite Materials for Use in Obtaining an
Approximate Value of Young’s Modulus
C816 Test Method for Sulfur Content in Graphite by
This guide is under the jurisdiction of ASTM Committee C28 on Advanced
Combustion-Iodometric Titration Method
Ceramics and is the direct responsibility of Subcommittee C28.07 on Ceramic
Matrix Composites.
Current edition approved Jan. 1, 2024. Published February 2024. Originally
approved in 2015. Last previous edition approved in 2015 as C1793 – 15. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/C1793-15R24. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The boldface numbers in parentheses refer to the list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1793 − 15 (2024)
C838 Test Method for Bulk Density of As-Manufactured C1683 Practice for Size Scaling of Tensile Strengths Using
Carbon and Graphite Shapes Weibull Statistics for Advanced Ceramics
C1773 Test Method for Monotonic Axial Tensile Behavior
C1039 Test Methods for Apparent Porosity, Apparent Spe-
of Continuous Fiber-Reinforced Advanced Ceramic Tubu-
cific Gravity, and Bulk Density of Graphite Electrodes
lar Test Specimens at Ambient Temperature
C1145 Terminology of Advanced Ceramics
D2766 Test Method for Specific Heat of Liquids and Solids
C1179 Test Method for Oxidation Mass Loss of Manufac-
(Withdrawn 2018)
tured Carbon and Graphite Materials in Air
D3171 Test Methods for Constituent Content of Composite
C1198 Test Method for Dynamic Young’s Modulus, Shear
Materials
Modulus, and Poisson’s Ratio for Advanced Ceramics by
D3529/D3529M Test Methods for Constituent Content of
Sonic Resonance
Composite Prepreg
C1233 Practice for Determining Equivalent Boron Contents
D3800 Test Method for Density of High-Modulus Fibers
of Nuclear Materials
D3878 Terminology for Composite Materials
C1239 Practice for Reporting Uniaxial Strength Data and
D4018 Test Methods for Properties of Continuous Filament
Estimating Weibull Distribution Parameters for Advanced
Carbon and Graphite Fiber Tows
Ceramics
D4284 Test Method for Determining Pore Volume Distribu-
C1259 Test Method for Dynamic Young’s Modulus, Shear
tion of Catalysts and Catalyst Carriers by Mercury Intru-
Modulus, and Poisson’s Ratio for Advanced Ceramics by
sion Porosimetry
Impulse Excitation of Vibration
D4850 Terminology Relating to Fabrics and Fabric Test
C1274 Test Method for Advanced Ceramic Specific Surface
Methods
Area by Physical Adsorption
D5528 Test Method for Mode I Interlaminar Fracture Tough-
C1275 Test Method for Monotonic Tensile Behavior of
ness of Unidirectional Fiber-Reinforced Polymer Matrix
Continuous Fiber-Reinforced Advanced Ceramics with
Composites
Solid Rectangular Cross-Section Test Specimens at Am-
D5600 Test Method for Trace Metals in Petroleum Coke by
bient Temperature
Inductively Coupled Plasma Atomic Emission Spectrom-
C1291 Test Method for Elevated Temperature Tensile Creep
etry (ICP-AES)
Strain, Creep Strain Rate, and Creep Time to Failure for
D5766 Test Method for Open-Hole Tensile Strength of
Monolithic Advanced Ceramics
Polymer Matrix Composite Laminates
C1292 Test Method for Shear Strength of Continuous Fiber-
D5961 Test Method for Bearing Response of Polymer Ma-
Reinforced Advanced Ceramics at Ambient Temperatures trix Composite Laminates
C1337 Test Method for Creep and Creep Rupture of Con- D6484 Test Method for Open-Hole Compressive Strength of
tinuous Fiber-Reinforced Advanced Ceramics Under Ten- Polymer Matrix Composite Laminates
sile Loading at Elevated Temperatures D6507 Practice for Fiber Reinforcement Orientation Codes
for Composite Materials
C1341 Test Method for Flexural Properties of Continuous
D6671 Test Method for Mixed Mode I-Mode II Interlaminar
Fiber-Reinforced Advanced Ceramic Composites
Fracture Toughness of Unidirectional Fiber Reinforced
C1358 Test Method for Monotonic Compressive Strength
Polymer Matrix Composites
Testing of Continuous Fiber-Reinforced Advanced Ce-
D7136 Test Method for Measuring the Damage Resistance
ramics with Solid Rectangular Cross Section Test Speci-
of a Fiber-Reinforced Polymer Matrix Composite to a
mens at Ambient Temperatures
Drop-Weight Impact Event
C1359 Test Method for Monotonic Tensile Strength Testing
D7137 Test Method for Compressive Residual Strength
of Continuous Fiber-Reinforced Advanced Ceramics With
Properties of Damaged Polymer Matrix Composite Plates
Solid Rectangular Cross Section Test Specimens at El-
D7219 Specification for Isotropic and Near-isotropic
evated Temperatures
Nuclear Graphites
C1360 Practice for Constant-Amplitude, Axial, Tension-
D7542 Test Method for Air Oxidation of Carbon and Graph-
Tension Cyclic Fatigue of Continuous Fiber-Reinforced
ite in the Kinetic Regime
Advanced Ceramics at Ambient Temperatures
E6 Terminology Relating to Methods of Mechanical Testing
C1425 Test Method for Interlaminar Shear Strength of 1D
E111 Test Method for Young’s Modulus, Tangent Modulus,
and 2D Continuous Fiber-Reinforced Advanced Ceramics
and Chord Modulus
at Elevated Temperatures
E132 Test Method for Poisson’s Ratio at Room Temperature
C1468 Test Method for Transthickness Tensile Strength of
E143 Test Method for Shear Modulus at Room Temperature
Continuous Fiber-Reinforced Advanced Ceramics at Am-
E228 Test Method for Linear Thermal Expansion of Solid
bient Temperature
Materials With a Push-Rod Dilatometer
C1470 Guide for Testing the Thermal Properties of Ad-
E261 Practice for Determining Neutron Fluence, Fluence
vanced Ceramics
Rate, and Spectra by Radioactivation Techniques
C1525 Test Method for Determination of Thermal Shock
Resistance for Advanced Ceramics by Water Quenching
C1557 Test Method for Tensile Strength and Young’s Modu- 4
The last approved version of this historical standard is referenced on
lus of Fibers www.astm.org.
C1793 − 15 (2024)
E289 Test Method for Linear Thermal Expansion of Rigid 3.1.7 fiber, n—a fibrous form of matter with an aspect ratio
Solids with Interferometry >10 and an effective diameter <1 mm. (Synonym – filament)
E408 Test Methods for Total Normal Emittance of Surfaces D3878
Using Inspection-Meter Techniques
3.1.7.1 Discussion—A fiber/filament forms the basic ele-
E423 Test Method for Normal Spectral Emittance at El-
ment of fabrics and other textile structures.
evated Temperatures of Nonconducting Specimens
3.1.8 fiber areal weight, n—the mass per unit area of the
E1269 Test Method for Determining Specific Heat Capacity
fibrous reinforcement of a composite material.
by Differential Scanning Calorimetry
D3529/D3529M
E1309 Guide for Identification of Fiber-Reinforced
3.1.9 fiber content/fraction (volume or weight), n—the
Polymer-Matrix Composite Materials in Databases (With-
amount of fiber present in a composite, expressed either as a
drawn 2015)
percent by weight or a percent by volume. D3878
E1461 Test Method for Thermal Diffusivity by the Flash
Method 3.1.10 fiber preform, n—a preshaped fibrous reinforcement,
normally without matrix, but often containing a binder to
E1922 Test Method for Translaminar Fracture Toughness of
Laminated and Pultruded Polymer Matrix Composite facilitate manufacture, formed by distribution/weaving of fi-
Materials bers to the approximate contour and thickness of the finished
E2586 Practice for Calculating and Using Basic Statistics part. D3878
2.2 Non-ASTM Standards:
3.1.11 fill, n—in a woven fabric, the yarn running from
CMH-17, Volume 5 Composite Materials Handbook (CMC
selvage to selvage at right angles to the warp. D3878
Handbook)
3.1.12 hybrid, n—(for composite materials) containing at
ASME B46.1-2009 Surface Texture (Surface Roughness,
least two distinct types of matrix or reinforcement. Each matrix
Waviness, and Lay)
or reinforcement type can be distinct because of its (a) physical
or mechanical properties, or both, (b) material form, or (c)
3. Terminology
chemical composition. D3878
3.1 Definitions:
3.1.13 injection molding, n—in composite fabrication, the
3.1.1 General—Many of the terms in this guide for speci-
process of forcing liquid polymer under pressure into a closed
fications are defined in the terminology standards for ceramic
mold that contains a fiber preform.
whitewares (C242), advanced ceramics (C1145), composite
materials (D3878), fabrics and test methods (D4850), and 3.1.14 knitted fabric, n—a fiber structure produced by inter-
mechanical testing (E6).
looping one or more ends of yarn or comparable material.
3.1.2 apparent porosity, n—the volume fraction of all pores, D4850
voids, and channels within a solid mass that are interconnected
3.1.15 laminate, n—any fiber- or fabric-reinforced compos-
with each other and communicate with the external surface,
ite consisting of laminae (plies) with one or more orientations
and thus are measurable by gas or liquid penetration. (Syn-
with respect to some reference direction. D3878
onym – open porosity) C242
3.1.16 lay-up, n—a process or fabrication involving the
3.1.3 braided fabric, n—a woven structure produced by
placement of successive layers of materials in specified se-
interlacing three or more ends of yarns in a manner such that
quence and orientation. E1309, D6507
the paths of the yarns are diagonal to the vertical axis of the
3.1.17 matrix, n—the continuous constituent of a composite
fabric. D4850
material, which surrounds or engulfs the embedded reinforce-
3.1.3.1 Discussion—Braided structures can have 2D or 3D ment in the composite and acts as the load transfer mechanism
architectures. between the discrete reinforcement elements. D3878
3.1.4 bulk density, n—the mass of a unit volume of material
3.1.18 matrix content, n—the amount of matrix present in a
including both permeable and impermeable voids. D7219
composite expressed either as a percent by weight or a percent
by volume. D3878
3.1.5 ceramic matrix composite, n—a material consisting of
two or more materials (insoluble in one another), in which the
3.1.19 ply, n—in 2D laminar composites, the constituent
major, continuous component (matrix component) is a ceramic,
single layer as used in fabricating, or occurring within, a
while the secondary component(s) (reinforcing component)
composite structure. D3878
may be ceramic, glass-ceramic, glass, metal or organic in
3.1.20 prepreg, n—the admixture of fibrous reinforcement
nature. These components are combined on a macroscale to
and polymeric matrix used to fabricate composite materials. Its
form a useful engineering material possessing certain proper-
form may be sheet, tape, or tow. For thermosetting polymer, the
ties or behavior not possessed by the individual constituents.
polymer has been partially cured to a controlled viscosity
C1145
called “B stage.” D3878
3.1.6 fabric, n—in textiles, a planar structure consisting of
3.1.21 selvage, n—the woven edge portion of a fabric
yarns or fibers. D4850
parallel to the warp. D3878
3.1.22 tow, n—in fibrous composites, a continuous, ordered
Available from American Society of Mechanical Engineers (ASME), ASME
assembly of essentially parallel, collimated continuous
International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org. filaments, normally without twist. (Synonym – roving) D3878
C1793 − 15 (2024)
3.1.23 unidirectional composite, n—any fiber reinforced composition, thickness, phase content, and morphology/
composite with all fibers aligned in a single direction. D3878 microstructure are used to control that interface strength. (9,
10)
3.1.24 warp, n—the yarn running lengthwise in a woven
fabric. D3878
3.2.6 hot press and sinter densification, n—in SiC matrix
composites, a matrix production and densification process in
3.1.25 woven fabric, n—a fabric structure produced by the
which silicon carbide particulate in the preform are consoli-
interlacing, in a specific weave pattern, of tows or yarns
dated and sintered together to high density in a die press at high
oriented in two or more directions.
pressures and temperatures.
3.1.25.1 Discussion—There are a large variety of 2D weave
3.2.6.1 Discussion—A sintering additive is often added to
styles, e.g., plain, satin, twill, basket, crowfoot, etc.
the silicon carbide powders to produce liquid phase sintering
3.1.26 yarn, n—in fibrous composites, a continuous, ordered
and accelerate densification.
assembly of essentially parallel, collimated filaments, normally
3.2.7 infiltration and pyrolysis densification, n—in SiC ma-
with twist, and of either discontinuous or continuous filaments.
trix composites, a matrix production and densification process
Single yarn – an end in which each filament follows the same
in which a liquid silicone-organic polymer precursor is
twist. D3878
infiltrated/impregnated into the porous perform or the partially
3.2 Definitions of Terms Specific to This Standard:
porous composite and pyrolyzed to form the silicon carbide
3.2.1 1D, 2D, and 3D reinforcement, n—a description of the
matrix.
orientation and distribution of the reinforcing fibers and yarns
3.2.7.1 Discussion—Pyrolysis of the silicone-organic pre-
in a composite.
cursor in an inert atmosphere converts the precursor to a silicon
3.2.1.1 Discussion—In a 1D structure, all of the fibers are
carbide form with the desired purity and crystal structure. The
oriented in a single longitudinal (x) direction. In a 2D structure,
infiltration/pyrolysis process may be iteratively repeated to fill
all of the fibers lie in the x-y planes of the plate or bar or in the
the porosity and build up the density in the composite. (11)
circumferential shells (axial and circumferential directions) of
3.2.8 melt infiltration, n—in SiC matrix composites, the
the rod or tube with no fibers aligned in the z or radial
matrix production and densification process in which molten
directions. In a 3D structure, the structure has fiber reinforce-
silicon is injected in a preform (containing SiC fibers and SiC
ment in the x-y-z directions in the plate or bar and in the axial,
and carbon particulate) and the molten silicon reacts with the
circumferential, and radial directions in a tube or rod.
free carbon to form a bonding silicon carbide matrix. (Syn-
3.2.2 axial tensile strength, n—for a composite tube or solid
onyms – reaction sintering, liquid silicon infiltration) (12)
round rod, the tensile strength along the long axis of the tube
3.2.9 primary structural axis, n—in a composite flat plate or
or rod. For a composite flat plate or rectangular bar, the tensile
rectangular bar, the directional axis defined by the loading
strength along the primary structural axis/direction.
axis/direction with the highest required tensile strength.
3.2.3 chemical vapor deposition or infiltration, n—a chemi-
3.2.9.1 Discussion—The primary structural axis is com-
cal process in which a solid material is deposited on a substrate
monly the axis with the highest fiber loading. This axis may not
or in a porous preform through the decomposition or the
be parallel with the longest dimension of the plate/bar/
reaction of gaseous precursors.
structure.
3.2.3.1 Discussion—Chemical vapor deposition is com-
monly done at elevated temperatures in a controlled atmo- 3.2.10 pyrolysis, n—in SiC matrix composites, the con-
sphere. trolled thermal process in which a silicone-organic precursor is
decomposed in an inert atmosphere to form the silicon carbide
3.2.4 durability, n—the measure of the ability of a material
(SiC) matrix.
or structure to endure and maintain its essential and distinctive
3.2.10.1 Discussion—Pyrolysis commonly results in weight
chemical, physical, mechanical and other functional character-
loss and the release of hydrogen and hydrocarbon vapors.
istics in a specific environment of use (temperature,
atmosphere, stress, radiation, etc) for a designated period of
3.2.11 rectangular bar, n—a solid straight rod with a rect-
time.
angular cross-section, geometrically defined by a width, a
thickness, and a long axis length.
3.2.5 fiber interface coating, n—in ceramic composites, a
coating applied to fibers to control the bonding between the
3.2.12 round rod, n—a solid elongated straight cylinder,
fiber and the matrix.
geometrically defined by an outer diameter and an axial length.
3.2.5.1 Discussion—It is common practice in SiC-SiC com-
3.2.13 round tube, n—a hollow elongated cylinder, geo-
posites to provide a thin (<3 micrometers) interface coating on
metrically defined by a outer diameter, an inner diameter, and
the surface of the fibers/filaments to prevent strong bonding
an axial length.
between the SiC fibers and the SiC matrix. A weak bond
between the fiber and the matrix in the SiC-SiC composite 3.2.14 silicon carbide – silicon carbide composite, n—a
permits the fibers to bridge matrix cracks and promotes ceramic matrix composite in which the reinforcing phase
mechanical toughness and damage tolerant failure; a strong consists of continuous silicon carbide filaments in the form of
bond between the matrix and the fiber produces low strain, fiber, continuous yarn, or a woven or braided fabric contained
brittle failure. Fiber interface coatings with controlled within a continuous matrix of silicon carbide. (13-15)
C1793 − 15 (2024)
3.2.15 silicon carbide fibers, n—inorganic fibers with a 4.4 The guide is applicable to SiC-SiC composites with flat
primary (≥80 weight%) silicon carbide (stoichiometric SiC plate, rectangular bar, round rod, and round tube geometries.
formula) composition.
4.5 This guide may also be applicable to the development of
3.2.15.1 Discussion—Silicon carbide fibers are commonly
specifications for SiC-SiC composites used for other structural
produced by two methods—the high temperature pyrolysis and
applications, discounting the nuclear-specific chemical purity
sintering of silicone-organic precursor fibers in an inert atmo-
and irradiation behavior requirements.
sphere and the chemical vapor deposition of silicon carbide on
a substrate filament. (16)
5. Silicon Carbide-Silicon Carbide Composites for
Nuclear Applications
3.2.16 surface seal coatings, n—an inorganic protective
coating applied to the outer surface of a SiC-SiC composite
5.1 Silicon carbide-silicon carbide (SiC-SiC) composites
component to protect against high temperature oxidation
are candidate structural materials for use in nuclear reactors,
and/or corrosion attack or to improve wear and abrasion
because of their high temperature stability, oxidation
resistance. Such coatings are commonly hard, impermeable
resistance, radiation tolerance, and low neutron cross-section
ceramic/glass coatings.
compared to metals and for their damage tolerance and tailored
anisotropic mechanical and physical properties, compared to
4. Significance and Use
monolithic ceramics. (1-8)
4.1 Composite materials consist by definition of a reinforce-
5.2 SiC-SiC composites are composed of silicon carbide
ment phase in a matrix phase. In addition, ceramic matrix
fiber reinforcement in a silicon carbide matrix. The chemical
composites (CMCs) often contain measurable porosity which
and phase composition, microstructure, and properties of the
interacts with the reinforcement and matrix. And SiC-SiC
fibers and the silicon carbide matrix, the fiber architecture (the
composites often use a fiber interface coating which has an
shape and morphology of the fiber preform, multidimensional
important mechanical function. The composition and structure
fiber distribution, and volume content of the fiber
of these different constituents in the CMC are commonly
reinforcement), and the composite density and porosity are
tailored for a specific application with detailed performance
engineered to give the desired performance properties for the
requirements. The tailoring involves the selection of the
composite. The SiC fibers generally have a fiber interface
reinforcement fibers (composition, properties, morphology,
coating to control the bonding and sliding between the SiC
etc.), the matrix (composition, properties, and morphology),
fiber and the SiC matrix. (13-15)
the composite structure (component fractions, reinforcement
architecture, interface coatings, porosity structure, 5.3 The physical, mechanical, and thermal properties of
microstructure, etc.), and the fabrication conditions (forming, SiC-SiC composites are determined by the complex interaction
assembly, forming, densification, finishing, etc.). The final of the constituents (fiber, interface coating, matrix, porosity) in
engineering properties (physical, mechanical, thermal, terms of the constituent chemistry, phase composition,
electrical, etc.) can be tailored across a broad range with major microstructure, properties, and fractional content; the fiber
directional anisotropy in the properties. architecture; the fiber-matrix bonding, and the effect of fabri-
cation on the constituent properties, morphology, and their
4.2 Specifications for specific CMC components covering
physical interactions. These factors can be synergistically
materials, material processing, and fabrication procedures are
tailored to produce a structure/component with the desired
developed to provide a basis for fabricating reproducible and
mechanical, physical, and thermal properties. The SiC-SiC
reliable structures. Designer/users/producers have to write
composite properties can be tailored for directional properties
CMC specifications for specific applications with well-defined
by the anisotropic architecture of the silicon carbide fiber
composition, structure, properties and processing require-
reinforcement. (13-15)
ments. But with the extensive breadth of selection in
5.4 Silicon carbide fibers produced by the polymer precur-
composition, structure, and properties in CMCs, it is virtually
impossible to write a "generic" CMC specification applicable sor route are commonly small diameter (5 μm to 20 μm)
continuous filaments. (16) The mechanical and thermal prop-
to any and all CMC applications that has the same type of
structure and details of the commonly-used specifications for erties of the silicon carbide fibers are strongly dependent on the
metal alloys. This guide is written to assist the designer/user/ silicon carbide stoichiometry, oxygen and impurity levels, the
producer in developing a comprehensive and detailed material phase composition and fractions, and the crystallite size and
specification for a specific CMC application/component with a orientation in the fibers. These factors are determined by the
specific focus on nuclear applications. precursor chemistry and the fabrication process conditions.
4.3 The purpose of this guide is to provide guidance on how 5.5 The silicon carbide fibers are commonly consolidated
to specify the constituents, the structure, the desired engineer- into high count multifilament tows which can be wound,
ing properties (physical, chemical, mechanical, durability, etc), wrapped or layed-up into 1D structures, woven/layed-up/
methods of testing, manufacturing process requirements, the braided/knitted into 2D structures, or woven/braided/knitted/
quality assurance requirements, and traceability for SiC-SiC stitched into 3D structures. Each of these fiber structures are
composites for nuclear reactor applications. The resulting fabricated with defined fiber architectures, offering a wide
specification may be used for the design, production, range of bulk fiber content. Different fiber architectures may
evaluation, and qualification of SiC-SiC composites for struc- have marked reinforcement anisotropy, depending on the
tures in nuclear reactors. relative fiber content in each orthogonal direction.
C1793 − 15 (2024)
NOTE 1—Many commercially available SiC-SiC composites consist of
processing manufacture and non-destructive testing (NDT) of
stacked fabric plies with a two dimensional woven fabric architecture. The
the SiC-SiC composite.
SiC-SiC composite is densified to produce a final structure with orthotro-
pic or quasi-isotropic mechanical and thermal properties.
7. Product Specification—Composite Constituents,
5.6 The silicon carbide matrix in SiC-SiC composites is
Chemical Composition and Purity for Nuclear
commonly produced by four methods: (1) a chemical vapor
Applications
infiltration process, (2) an iterative precursor liquid infiltration/
7.1 A SiC-SiC composite shall consist of silicon carbide
pyrolysis process, (3) a silicon melt infiltration process, or (4)
reinforcement fibers in a silicon carbide matrix. The fibers may
hot pressing and sintering of SiC powders. The four matrix
have a fiber interface coating/treatment to control the bonding
formation processes use different precursors and different
between the fiber and the matrix.
processing conditions, which produce differences in the
7.2 The composite may have a surface coating to seal the
chemistry, phase composition and fractions, crystallinity,
composite against gas and liquid penetration/escape and to
morphology, and microstructure (density, pores, and cracks) in
protect the composite from oxidation or environmental degra-
the silicon carbide matrix. Two or more of these matrix
dation.
densification processes may be combined for a hybrid silicon
carbide matrix.
7.3 The designer/purchaser/user shall specify the required
composite constituents and structures in terms of silicon
5.7 The interaction of these four variable factor sets [(1)
carbide fibers, fiber interface coatings, silicon carbide matrix,
silicon carbide fiber type and properties; (2) fiber interface
and surface seal coatings. The specification shall list sources,
coating; (3) fiber content, tow structure, and architecture; (4)
chemical compositions and phase content, component fractions
matrix composition and properties, phase content, crystallinity,
and morphology, reinforcement architecture, and seal coating
density, morphology, and porosity] can produce SiC-SiC com-
requirements, as required by the designer/purchaser/user. Sec-
posites with a wide range of mechanical and physical
tion 11 describes the manufacturing process specification
properties, along with tailored anisotropic properties in the
requirements for fibers, interface coatings, matrix, architecture,
major directions.
and seal coatings.
NOTE 2—For nuclear applications, SiC-SiC composites made from
stoichiometric, high purity, and fully crystalline SiC fibers and matrices
7.4 For nuclear applications impurity levels in SiC-SiC
are preferred for their physical, chemical, and mechanical property
composites (and any surface seal coatings) have to be carefully
stability in the temperature and high radiation flux conditions of light
controlled to minimize parasitic neutron absorption, oxidation
water fission reactors and high temperature fission reactors. (1-8)
promoting catalysis, nuclear activation impurities, corrosion
promotion impurities, and fissionable elements. The designer/
6. Product Specifications—Properties, Materials and
purchaser/user shall specify the requirements and test methods
Processing
for chemical purity based on the defined requirements for the
6.1 The fibers, matrix, fiber architecture, fiber interface
specific nuclear application. (An example of chemical purity
coatings, any surface seal coatings, and the method of
requirements for nuclear grade graphite (from Specification
manufacture, when combined as a SiC-SiC composite
D7219) is given in Table X1.1.)
structure, must produce a composite that consistently and
NOTE 3—Table X1.2 (from D7219) contains a list of chemical impuri-
reliably meets the performance requirements (chemical,
ties typically found in nuclear grade graphite and carbon. The impurities
physical, mechanical, and durability) specified by the designer/
are categorized as neutron absorbing impurities, oxidation promoting
catalysts, activation relevant impurities, metallic corrosion relevant
purchaser/user, applicable codes and standards, and the con-
impurities, and fissile/fissionable elements. The suggested limits represent
trolling regulatory agency.
the reactor designer’s preferences for chemical purity in graphite, which
6.2 The engineering properties and characteristics of a may be extended to silicon carbide.
composite structure are manufactured into the structure as part
7.5 The designer/purchaser/user shall specify boron equiva-
of the fabrication process. Specifications for SiC-SiC compos-
lent limits and test methods for the specific nuclear application.
ites shall be written to define requirements for end product
The boron equivalent shall be calculated in accordance with
properties (chemical constituents and phase composition,
Practice C1233 as specified for nuclear grade graphite (refer-
physical properties, mechanical properties, durability, etc.),
enced in Table X1.1).
and manufacturing specifications for starting materials and
7.6 Each SiC-SiC composite production lot sampled in
fabrication. The manufacturing specifications shall include
accordance with Section 14 shall conform to the requirements
sufficient information to ensure that critical factors and param-
for chemical purity and boron equivalency specified by the
eters in the starting materials and the manufacturing process
designer/purchaser/user.
are identified and controlled to produce the final structure/
component to the defined specification.
8. Product Specification—Physical Properties
6.3 The designer/purchaser/user shall define the specifica-
8.1 The designer/purchaser/user shall specify the required
tions for the constituents (chemistry and properties),
minimum/maximum values for the specified physical, thermal,
architecture, final properties, and quality assurance for the
and electrical properties of SiC-SiC composites based on the
SiC-SiC composite.
desired performance properties; the component constituents,
6.4 The designer/purchaser/user and the manufacturer to- fractions, and properties; the reinforcement architecture; and
gether shall define the specifications for the materials/ the final porosity fraction.
C1793 − 15 (2024)
8.2 The physical, thermal, and electrical properties, of 9. Product Specification—Mechanical Properties
SiC-SiC composites that are of primary and secondary interest
9.1 The designer/purchaser/user shall specify the required
are listed in Table 1 with the recommended ASTM test
maximum/minimum values for the selected mechanical prop-
standards. The selection of specific physical, thermal, and
erties of SiC-SiC composites considering anisotropy and based
electrical properties for the specification will depend on the
on the desired performance properties, the component constitu-
design requirements for the CMC component. Other properties
ents and fractions, and the reinforcement architecture.
(not included in this list) may be specified by the designer/
9.2 Mechanical property specifications for each kind of
purchaser/user, based on application-specific requirements.
stress test should include (per designer/ purchaser/user require-
8.2.1 The designer/purchaser/user may define anisotropy
ments): (1) the ultimate strength and strain, (2) the fracture
requirements and limits for designated physical properties.
strength and strain, (3) the proportional limit stress and strain,
8.3 The designer/purchaser/user may specify requirements
(4) elastic modulus, and (5) representative stress-strain curves.
for descriptive statistics and limits (test count, mean, standard
deviations, coefficient of variation, minimum/maximum 9.3 The stress-strain response of a SiC-SiC composite can
values, etc.) for the designated physical properties (see Practice
vary widely, ranging from linear elastic brittle failure to very
E2586). high strain failure with major damage accumulation and
pseudo-ductility (see Fig. 1). The stress-strain response of the
8.4 Elevated Temperatures—The designer/purchaser/user
composite depends on the interaction of many factors—fiber
may also specify requirements for thermal and electrical
properties, architecture, and volume fraction, matrix density
properties at specified elevated temperatures, determined by
and properties, matrix-fiber bonding, stress alignment with the
the performance requirements.
reinforcement axes, and deformation/damage mechanisms.
8.5 The designer/purchaser/user may specify requirements
9.4 The mechanical properties of SiC-SiC composites that
for anisotropy in thermal and electrical properties, determined
are of interest are listed in Table 2 with the recommended
by the performance requirements.
ASTM test standards. The selection of specific properties for
8.6 Variability in physical properties (in-piece anisotropy,
the specification will depend on the design requirements for the
in-piece volumetric, piece-to-piece, and lot-to-lot) may be of
specific SiC-SiC component.
direct interest to the manufacturer and the designer/purchaser/
9.4.1 Elevated Temperatures—The designer/purchaser/user
user.
may specify requirements for mechanical properties at specific
8.7 Other physical properties may be specified by the
elevated temperatures, determined by the performance require-
designer/purchaser/user [see Composite Materials Handbook
ments.
CMH-17, Volume 5 (CMC Handbook)].
9.4.2 Anisotropy—The designer/purchaser/user may define
8.8 Each SiC-SiC composite production lot shall be anisotropy requirements and limits for designated mechanical
properties.
sampled in accordance with Section 14.
TABLE 1 Physical, Thermal and Electrical Properties of SiC-SiC Composites
NOTE 1—For round rods and tubes, anisotropy should be defined in terms of axial, radial, and tangential (hoop) directions, not x, y, and z.
NOTE 2—Thermal expansion, thermal conductivity, electrical resistivity, and emissivity data may be anisotropic depending on fiber architecture and
should be measured in the major directions.
NOTE 3—Physical properties may be strongly dependent on bulk porosity content and on localized porosity concentrations (which may be
inhomogeneously distributed).
Units ASTM Test Priority Anisotropy
Bulk Density by Physical Measurement g/cm C559, C838 Primary No
Apparent Porosity and Bulk Density by Immersion % and g/cm C1039 Primary No
Constituent (Fiber, Matrix) Bulk Fraction % D3171 (Method 2) Primary No
Fiber Fraction–Directional % By calculation Primary Yes (x,y,z)
Matrix SiC Crystallinity (Phase Content and Fractions) % TBD Primary No
Fiber SiC Crystallinity (Phase Content and Fractions) % TBD Primary No
Linear Thermal Expansion ppm/°C C1470, E228, E289 Secondary Yes (x,y,z)
Thermal Conductivity – (Diffusivity) W/(m-K) – (m /s) C1470, C714, E1461 Secondary Yes (x,y,z)
Specific Heat J/(g-K) C1470, D2766, E1269 Secondary No
Emittance, Emissivity nd C1470, E408, E423 Secondary Yes (x,y,z)
A
Electrical Resistivity Ohm-m C611 Secondary Yes (x,y,z)
Porosity Content and Structure (Mercury Porosimetry) TBD D4284 Secondary No
Surface Area (BET) m /g C1274 Secondary No
2 A
Permeability L /(m -s) C577 Secondary Yes (x,y,z)
Surface Roughness TBD Surface Profilometry Secondary Yes (x,y,z)
ASME B46.1
A
Modification of this test method may be required for SiC-SiC composites.
nd = no dimensions.
TBD = to be determined.
C1793 − 15 (2024)
S = ultimate strength, MPa
U
ɛ = ultimate strain, %
U
S = fracture strength, MPa
F
ɛ = fracture strain, %
F
σ = proportional limit stress, MPa
O
ɛ = proportional limit strain, %
O
E = elastic modulus, GPa
U = modulus of resilience (J/m ) integral of σ from 0 to ɛ strain
R O
U = modulus of toughness (J/m ) integral of σ from 0 to ɛ strain
T F
FIG. 1 Examples of Different SiC-SiC Stress-Strain Curves
TABLE 2 Mechanical Properties of SiC-SiC Composites
NOTE 1—Mechanical properties may be strongly anisotropic (axial, transverse, off-axis, etc) depending on fiber architecture and directional fiber
fraction and should be measured in the major directions.
NOTE 2—Mechanical properties may be strongly dependent on bulk porosity content and on porosity concentrations (which may be inhomogeneously
distributed).
ASTM Test – ASTM Test –
Units
Flats-Bars Rods/Tubes
Tensile Properties (ultimate, fracture, PropL) MPa & strain C1275, C1359 C1773
B
Flexure Properties (ultimate, fracture, PropL) MPa & strain C1341
B
Compression Properties (ultimate, fracture, PropL) MPa & strain C1358
B
Shear Properties (ultimate, fracture, PropL) MPa & strain C1292, C1425
B
Transthickness Tensile Properties (ultimate, fracture, PropL) MPa & strain C1468
B
Hoop Strength Properties (ultimate, fracture, PropL) MPa & strain NA
A A
Elastic/Shear Modulus by Mechanical Loading GPa E111, E143 E111 , E143
A
Elastic/Shear Modulus by Sonic Resonance GPa C1198 C1198
A
Elastic/Shear Modulus by Impulse Excitation GPa C1259 C1259
A
Elastic Modulus by Sonic Velocity GPa C769 C769
Poisson’s Ratio nd E132 E132
Modulus of Resilience (in Tension) J/m C1275, C1359 C1773
Modulus of Toughness (in Tension) J/m C1275, C1359 C1773
A B
Open Hole Tensile Strength Properties MPa & strain D5766
A B
Open Hole Compression Strength Properties MPa & strain D6484
B B
Notch Tensile Strength Properties MPa & strain
B B
Notch Compression Strength Properties MPa & strain
A B
Pin Bearing Strength Properties MPa & strain D5961
2 A A A B
Crack Growth Resistance/ Strain Energy Release Rate/ kJ/m D5528 , D6671 , E1922
(Fracture Toughness) (Interlaminar and Translaminar)
A
Modification of this polymer matrix composite test method may be required.
B
New test methods are required.
nd = no dimensions.
9.4.3 The designer/purchaser/user may specify require-
ments for descriptive statistics and limits (test count, mean,
C1793 − 15 (2024)
will have different susceptibility to radiation damage based on crystal
standard deviations, coefficient of variation, minimum/
structure and impurities. The radiation damage effects should be assessed
maximum values, etc) for the designated mechanical properties
and understood for each specific component, including matrix, fiber,
(see Practice E2586).
interface coating, and surface seal coating.
9.4.4 The designer/purchaser/user may specify require-
10.2 Oxidation/corrosion effects at reactor operating tem-
ments for Weibull modulus and Weibull characteristic strength
peratures must by controlled and managed in terms of chemical
for selected mechanical properties (see Practices C1239 and
reactions, phase changes, mass loss/gain, dimensional changes,
C1683).
and corrosion products. Any degradation of physical and
9.5 Variability in mechanical properties (in-piece
mechanical properties of the composite as a whole, must be
volumetric, in-piece anisotropy, piece-to-piece, and lot-to-lot)
managed and minimized, including any fiber interface coating
may be of direct interest to the manufacturer and the designer/
and surface seal coating effects.
purchaser/user. The designer/purchaser/user may specify
10.3 Stress effects must be understood and controlled in
statistically-based requirements to characterize variability
terms of crack growth, flaw initiation, fatigue degradation,
across the different factors.
creep strain, and stress-rupture, all as a function of
9.6 Other mechanical property requirements may be speci-
temperature, time, stress levels, and oxidation/corrosion con-
fied by the designer/purchaser/user [see Composite Materials
ditions.
Handbook CMH-17, Volume 5 (CMC Handbook)].
10.4 The designer/purchaser/user shall specify the durabil-
9.7 Each SiC-SiC composite production lot shall be
ity requirements (physical, mechanical, etc.) for the SiC-SiC
sampled in accordance with Section 14.
composites under defined conditions of time, temperature,
neutron irradiation, stress, oxidation conditions, and corrosion
10. Product Specification—Durability Properties
concentrations. Durability requirements are commonly defined
10.1 The durability of SiC-SiC composites over time under
as a “not-to-exceed” maximum % change in designated prop-
reactor environment conditions is a principal engineering
erties as a function of exposure conditions and time. The
design concern. In a nuclear reactor, the composites must
specification shall define the experimental test methods and the
maintain a defined set of chemical, physical, and mechanical
required exposure-conditioning parameters for determining the
properties for extended periods of time under defined condi-
physical, chemical, and mechanical durability. (Table 3 is a list
tions of fast neutron radiation exposure, static and
...
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