ASTM C1674-23

Standard Test Method for Flexural Strength of Advanced Ceramics with Engineered Porosity (Honeycomb Cellular Channels) at Ambient Temperatures

SIGNIFICANCE AND USE
5.1 This test method is used to determine the mechanical properties in flexure of engineered ceramic components with multiple longitudinal hollow channels, commonly described as “honeycomb” channel architectures. The components generally have 30 % or more porosity and the cross-sectional dimensions of the honeycomb channels are on the order of 1 mm or greater.  
5.2 The experimental data and calculated strength values from this test method are used for material and structural development, product characterization, design data, quality control, and engineering/production specifications.
Note 1: Flexure testing is the preferred method for determining the nominal “tensile fracture” strength of these components, as compared to a compression (crushing) test. A nominal tensile strength is required, because these materials commonly fail in tension under thermal gradient stresses. A true tensile test is difficult to perform on these honeycomb specimens because of gripping and alignment challenges.  
5.3 The mechanical properties determined by this test method are both material and architecture dependent, because the mechanical response and strength of the porous test specimens are determined by a combination of inherent material properties and microstructure and the architecture of the channel porosity [porosity fraction/relative density, channel geometry (shape, dimensions, cell wall thickness, etc.), anisotropy and uniformity, etc.] in the specimen. Comparison of test data must consider both differences in material/composition properties as well as differences in channel porosity architecture between individual specimens and differences between and within specimen lots.  
5.4 Test Method A is a user-defined specimen geometry with a choice of four-point or three-point flexure testing geometries. It is not possible to define a single fixed specimen geometry for flexure testing of honeycombs, because of the wide range of honeycomb architectures and cell sizes and consid...
SCOPE
1.1 This test method covers the determination of the flexural strength (modulus of rupture in bending) at ambient conditions of advanced ceramic structures with 2-dimensional honeycomb channel architectures.  
1.2 The test method is focused on engineered ceramic components with longitudinal hollow channels, commonly called “honeycomb” channels (see Fig. 1). The components generally have 30 % or more porosity and the cross-sectional dimensions of the honeycomb channels are on the order of 1 mm or greater. Ceramics with these honeycomb structures are used in a wide range of applications (catalytic conversion supports (1),2 high temperature filters (2, 3), combustion burner plates (4), energy absorption and damping (5), etc.). The honeycomb ceramics can be made in a range of ceramic compositions—alumina, cordierite, zirconia, spinel, mullite, silicon carbide, silicon nitride, graphite, and carbon. The components are produced in a variety of geometries (blocks, plates, cylinders, rods, rings).
FIG. 1 General Schematics of Typical Honeycomb Ceramic Structures  
1.3 The test method describes two test specimen geometries for determining the flexural strength (modulus of rupture) for a porous honeycomb ceramic test specimen (see Fig. 2):
FIG. 2 Flexure Loading Configurations  
L = Outer Span Length (for Test Method A, L = User defined; for Test Method B, L = 90 mm)
Note 1: 4-Point-1/4 Loading for Test Methods A1 and B.
Note 2: 3-Point Loading for Test Method A2.  
1.3.1 Test Method A—A 4-point or 3-point bending test with user-defined specimen geometries, and  
1.3.2 Test Method B—A 4-point-1/4 point bending test with a defined rectangular specimen geometry (13 mm × 25 mm × > 116 mm) and a 90 mm outer support span geometry suitable for cordierite and silicon carbide honeycombs with small cell sizes.  
1.4 The test specimens are stressed to failure and the breaking force value, specimen and cell dimensions, and loa...

General Information

• Status: Published
• Publication Date: 31-May-2023
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: C28 - Advanced Ceramics
• Drafting Committee: C28.04 - Applications

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: C1674 − 23
Standard Test Method for
Flexural Strength of Advanced Ceramics with Engineered
Porosity (Honeycomb Cellular Channels) at Ambient
1
Temperatures
This standard is issued under the fixed designation C1674; 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 loading geometry data are used to calculate a nominal beam
strength, a wall fracture strength, and a honeycomb structure
1.1 This test method covers the determination of the flexural
strength.
strength (modulus of rupture in bending) at ambient conditions
1.5 Test results are used for material and structural
of advanced ceramic structures with 2-dimensional honeycomb
channel architectures. development, product characterization, design data, quality
control, and engineering/production specifications.
1.2 The test method is focused on engineered ceramic
1.6 The test method is meant for ceramic materials that are
components with longitudinal hollow channels, commonly
linear-elastic to failure in tension. The test method is not
called “honeycomb” channels (see Fig. 1). The components
applicable to polymer or metallic porous structures that fail in
generally have 30 % or more porosity and the cross-sectional
an elastomeric or an elastic-ductile manner.
dimensions of the honeycomb channels are on the order of
1 mm or greater. Ceramics with these honeycomb structures
1.7 The test method is defined for ambient testing tempera-
are used in a wide range of applications (catalytic conversion
tures. No directions are provided for testing at elevated or
2
supports (1), high temperature filters (2, 3), combustion
cryogenic temperatures.
burner plates (4), energy absorption and damping (5), etc.). The
1.8 The values stated in SI units are to be regarded as
honeycomb ceramics can be made in a range of ceramic
standard (IEEE/ASTM SI 10). English units are sparsely used
compositions—alumina, cordierite, zirconia, spinel, mullite,
in this standard for product definitions and tool descriptions,
silicon carbide, silicon nitride, graphite, and carbon. The
per the cited references and common practice in the US
components are produced in a variety of geometries (blocks,
automotive industry.
plates, cylinders, rods, rings).
1.9 This standard does not purport to address all of the
1.3 The test method describes two test specimen geometries
safety concerns, if any, associated with its use. It is the
for determining the flexural strength (modulus of rupture) for a
responsibility of the user of this standard to establish appro-
porous honeycomb ceramic test specimen (see Fig. 2):
priate safety, health, and environmental practices and deter-
1.3.1 Test Method A—A 4-point or 3-point bending test with
mine the applicability of regulatory limitations prior to use.
user-defined specimen geometries, and
1.10 This international standard was developed in accor-
1
1.3.2 Test Method B—A 4-point- ⁄4 point bending test with a
dance with internationally recognized principles on standard-
defined rectangular specimen geometry (13 mm × 25 mm × >
ization established in the Decision on Principles for the
116 mm) and a 90 mm outer support span geometry suitable for
Development of International Standards, Guides and Recom-
cordierite and silicon carbide honeycombs with small cell
mendations issued by the World Trade Organization Technical
sizes.
Barriers to Trade (TBT) Committee.
1.4 The test specimens are stressed to failure and the
2. Referenced Documents
breaking force value, specimen and cell dimensions, and
3
2.1 ASTM Standards:
C373 Test Methods for Determination of Water Absorption
and Associated Properties by Vacuum Method for Pressed
1
This test method is under the jurisdiction of ASTM Committee C28 on
Ceramic Tiles and Glass Tiles and Boil Method for
Advanced Ceramics and is the direct responsibility of Subcommittee C28.04 on
Applications.
Current edition approved June 1, 2023. Published July 2023. Originally approved
3
in 2008. Last previous edition approved in 2016 as C1674 – 16. DOI: 10.1520/ For referenced ASTM standards, visit the ASTM website, www.astm.org, or
C1674-23. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
2
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, We
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C1674 − 16 C1674 − 23
Standard Test Method for
Flexural Strength of Advanced Ceramics with Engineered
Porosity (Honeycomb Cellular Channels) at Ambient
1
Temperatures
This standard is issued under the fixed designation C1674; 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*Scope
1.1 This test method covers the determination of the flexural strength (modulus of rupture in bending) at ambient conditions of
advanced ceramic structures with 2-dimensional honeycomb channel architectures.
1.2 The test method is focused on engineered ceramic components with longitudinal hollow channels, commonly called
“honeycomb” channels. (Seechannels (see Fig. 1.)). The components generally have 30 % or more porosity and the cross-sectional
dimensions of the honeycomb channels are on the order of 1 mm or greater. Ceramics with these honeycomb structures are used
2
in a wide range of applications (catalytic conversion supports (1), high temperature filters (2, 3), combustion burner plates (4),
energy absorption and damping (5), etc.). The honeycomb ceramics can be made in a range of ceramic compositions—alumina,
cordierite, zirconia, spinel, mullite, silicon carbide, silicon nitride, graphite, and carbon. The components are produced in a variety
of geometries (blocks, plates, cylinders, rods, rings).
1.3 The test method describes two test specimen geometries for determining the flexural strength (modulus of rupture) for a porous
honeycomb ceramic test specimen (see Fig. 2):
1.3.1 Test Method A—A 4-point or 3-point bending test with user-defined specimen geometries, and
1
1.3.2 Test Method B—A 4-point- ⁄4 point bending test with a defined rectangular specimen geometry (13 mm × 25 mm × > 116
mm) and a 90 mm outer support span geometry suitable for cordierite and silicon carbide honeycombs with small cell sizes.
1.4 The test specimens are stressed to failure and the breaking force value, specimen and cell dimensions, and loading geometry
data are used to calculate a nominal beam strength, a wall fracture strength, and a honeycomb structure strength.
1.5 Test results are used for material and structural development, product characterization, design data, quality control, and
engineering/production specifications.
1.6 The test method is meant for ceramic materials that are linear-elastic to failure in tension. The test method is not applicable
to polymer or metallic porous structures that fail in an elastomeric or an elastic-ductile manner.
1
This test method is under the jurisdiction of ASTM Committee C28 on Advanced Ceramics and is the direct responsibility of Subcommittee C28.04 on Applications.
Current edition approved Dec. 15, 2016June 1, 2023. Published January 2017July 2023. Originally approved in 2008. Last previous edition approved in 20112016 as
C1674 – 11.C1674 – 16. DOI: 10.1520/C1674-16.10.1520/C1674-23.
2
The boldface numbers in parentheses refer to the list of references at the end of this standard.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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C1674 − 23
FIG. 1 General Schematics of Typical Honeycomb Ceramic Structures
L = Outer Span Length (for Test Method A, L = User defined; for Test Method B, L = 90 mm)
1
NOTE 1—4-Point- ⁄4 Loading for Test Methods A1 and B.
NOTE 2—3-Point Loading for Test Method A2.
FIG. 2 Flexure Loading Configurations
1.7 The test method is defined for ambient testing temperatures. No directions are provided for testing at elevated or cryogenic
temperatures.
1.8 The values stated in SI units are to be regarded as standard (IEEE/ASTM SI 10). English units are sparsely used in this
standard for product definitions and tool descriptions, per the cited references and common practice in the US automotive industry.
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and healthsafety, health, and environmental practices and determine
the applicability of regulatory limitations prior to use.
1.10 This international standard was developed in accordance with internationally recog
...