ASTM C1424-15(2019)
(Test Method)Standard Test Method for Monotonic Compressive Strength of Advanced Ceramics at Ambient Temperature
Standard Test Method for Monotonic Compressive Strength of Advanced Ceramics at Ambient Temperature
SIGNIFICANCE AND USE
4.1 This test method may be used for material development, material comparison, quality assurance, characterization, and design data generation.
4.2 Generally, resistance to compression is the measure of the greatest strength of a monolithic advanced ceramic. Ideally, ceramics should be compressively stressed in use, although engineering applications may frequently introduce tensile stresses in the component. Nonetheless, compressive behavior is an important aspect of mechanical properties and performance. Although tensile strength distributions of ceramics are probabilistic and can be described by a weakest-link failure theory, such descriptions have been shown to be inapplicable to compressive strength distributions in at least one study (1).3 However, the need to test a statistically significant number of compressive test specimens is not obviated. Therefore, a sufficient number of test specimens at each testing condition is required for statistical analysis and design.
4.3 Compression tests provide information on the strength and deformation of materials under uniaxial compressive stresses. Uniform stress states are required to effectively evaluate any nonlinear stress-strain behavior which may develop as the result of cumulative damage processes (for example, microcracking) which may be influenced by testing mode, testing rate, processing or compositional effects, microstructure, or environmental influences.
4.4 The results of compression tests of test specimens fabricated to standardized dimensions from a particular material or selected portions of a part, or both, may not totally represent the strength and deformation properties in the entire full-size product or its in-service behavior in different environments.
4.5 For quality control purposes, results derived from standardized compressive test specimens may be considered indicative of the response of the material from which they were taken for given primary processing conditions and post-proces...
SCOPE
1.1 This test method covers the determination of compressive strength including stress-strain behavior, under monotonic uniaxial loading of advanced ceramics at ambient temperature. This test method is restricted to specific test specimen geometries. In addition, test specimen fabrication methods, testing modes (force or displacement), testing rates (force rate, stress rate, displacement rate, or strain rate), allowable bending, and data collection and reporting procedures are addressed. Compressive strength as used in this test method refers to the compressive strength obtained under monotonic uniaxial loading. Monotonic loading refers to a test conducted at a constant rate in a continuous fashion, with no reversals from test initiation to final fracture.
1.2 This test method is intended primarily for use with advanced ceramics that macroscopically exhibit isotropic, homogeneous, continuous behavior. While this test method is intended for use on monolithic advanced ceramics, certain whisker- or particle-reinforced composite ceramics, as well as certain discontinuous fiber-reinforced composite ceramics, may also meet these macroscopic behavior assumptions. Generally, continuous fiber ceramic composites (CFCCs) do not macroscopically exhibit isotropic, homogeneous, continuous behavior and, application of this test method to these materials is not recommended.
1.3 Values expressed in this test method are in accordance with the International System of Units (SI) and IEEE/ASTM SI 10.
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established i...
General Information
Relations
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: C1424 − 15 (Reapproved 2019)
Standard Test Method for
Monotonic Compressive Strength of Advanced Ceramics at
Ambient Temperature
This standard is issued under the fixed designation C1424; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.1 This test method covers the determination of compres-
mendations issued by the World Trade Organization Technical
sivestrengthincludingstress-strainbehavior,undermonotonic
Barriers to Trade (TBT) Committee.
uniaxial loading of advanced ceramics at ambient temperature.
This test method is restricted to specific test specimen geom-
2. Referenced Documents
etries. In addition, test specimen fabrication methods, testing
2.1 ASTM Standards:
modes (force or displacement), testing rates (force rate, stress
C773Test Method for Compressive (Crushing) Strength of
rate, displacement rate, or strain rate), allowable bending, and
Fired Whiteware Materials
data collection and reporting procedures are addressed. Com-
C1145Terminology of Advanced Ceramics
pressive strength as used in this test method refers to the
D695Test Method for Compressive Properties of Rigid
compressive strength obtained under monotonic uniaxial load-
Plastics
ing. Monotonic loading refers to a test conducted at a constant
E4Practices for Force Verification of Testing Machines
rate in a continuous fashion, with no reversals from test
E6Terminology Relating to Methods of MechanicalTesting
initiation to final fracture.
E83Practice for Verification and Classification of Exten-
1.2 This test method is intended primarily for use with
someter Systems
advanced ceramics that macroscopically exhibit isotropic,
E337Test Method for Measuring Humidity with a Psy-
homogeneous, continuous behavior. While this test method is
chrometer (the Measurement of Wet- and Dry-Bulb Tem-
intended for use on monolithic advanced ceramics, certain
peratures)
whisker- or particle-reinforced composite ceramics, as well as
E1012Practice for Verification of Testing Frame and Speci-
certain discontinuous fiber-reinforced composite ceramics,
men Alignment Under Tensile and Compressive Axial
may also meet these macroscopic behavior assumptions.
Force Application
Generally, continuous fiber ceramic composites (CFCCs) do
IEEE/ASTM SI 10American National Standard for Metric
not macroscopically exhibit isotropic, homogeneous, continu-
Practice
ous behavior and, application of this test method to these
materials is not recommended.
3. Terminology
1.3 Values expressed in this test method are in accordance
3.1 Definitions:
withtheInternationalSystemofUnits(SI)andIEEE/ASTMSI
3.1.1 The definitions of terms relating to compressive test-
10.
ing appearing in Terminology E6, Test Method D695, and
Terminology C1145 may apply to the terms used in this test
1.4 This standard does not purport to address all of the
method. Pertinent definitions as listed in Practice E1012,
safety concerns, if any, associated with its use. It is the
Terminology C1145, and Terminology E6 are shown in the
responsibility of the user of this standard to establish appro-
following with the appropriate source given in parentheses.
priate safety, health, and environmental practices and deter-
Additional terms used in conjunction with this test method are
mine the applicability of regulatory limitations prior to use.
defined in the following.
1.5 This international standard was developed in accor-
3.1.2 advanced ceramic, n—a highly engineered, high-
dance with internationally recognized principles on standard-
performance, predominately nonmetallic, inorganic, ceramic
material having specific functional attributes. (C1145)
This test method is under the jurisdiction of ASTM Committee C28 on
Advanced Ceramics and is the direct responsibility of Subcommittee C28.01 on
Mechanical Properties and Performance. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedJuly1,2019.PublishedJuly2019.Originallypublished contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
in 1999. Last previous edition approved in 2015 as C1424–15. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
C1424-15R19. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1424 − 15 (2019)
3.1.3 axial strain, [L/L], n—the average longitudinal strains represent the strength and deformation properties in the entire
measured at the surface on opposite sides of the longitudinal full-sizeproductoritsin-servicebehaviorindifferentenviron-
axis of symmetry of the specimen by two strain-sensing ments.
devices located at the mid length of the reduced section.
4.5 For quality control purposes, results derived from stan-
(E1012)
dardized compressive test specimens may be considered in-
3.1.4 bending strain, [L/L], n—the difference between the
dicative of the response of the material from which they were
strainatthesurfaceandtheaxialstrain.Ingeneral,thebending
taken for given primary processing conditions and post-
strain varies from point to point around and along the reduced
processing heat treatments.
section of the test specimen. (E1012)
5. Interferences
3.1.5 breaking load, [F], n—the load at which fracture
occurs. (E6) 5.1 Testenvironment(vacuum,inertgas,ambientair,andso
forth), including moisture content (for example, relative
3.1.6 compressive strength, [F/L ], n—the maximum com-
humidity), may have an influence on the measured compres-
pressive stress which a material is capable of sustaining.
sive strength. Testing to evaluate the maximum strength
Compressive strength is calculated from the maximum load
potential of a material can be conducted in inert environments
during a compression test carried to rupture and the original
or at sufficiently rapid testing rates, or both, so as to minimize
cross-sectional area of the specimen. (E6)
any environmental effects. Conversely, testing can be con-
3.1.7 gage length, [L], n—theoriginallengthofthatportion
ducted in environments, test modes, and test rates representa-
of the specimen over which strain or change of length is
tive of service conditions to evaluate material performance
determined. (E6)
under use conditions. When testing is conducted in uncon-
3.1.8 modulus of elasticity, [F/L ], n—the ratio of stress to
trolled ambient air with the intent of evaluating maximum
corresponding strain below the proportional limit. (E6)
strength potential, relative humidity and temperature must be
3.1.9 percent bending, n—the bending strain times 100 monitored and reported.
divided by the axial strain. (E1012)
5.2 Fabricationoftestspecimenscanintroducedimensional
variations which may have pronounced effects on compressive
4. Significance and Use
mechanical properties and behavior (for example, shape and
4.1 Thistestmethodmaybeusedformaterialdevelopment,
level of the resulting stress-strain curve, compressive strength,
material comparison, quality assurance, characterization, and
induced bending, and so forth). Machining effects introduced
design data generation.
duringtestspecimenpreparationcanbeaninterferingfactorin
the determination of ultimate strength of pristine material (that
4.2 Generally, resistance to compression is the measure of
is, increased frequency of loading block related fractures (see
thegreateststrengthofamonolithicadvancedceramic.Ideally,
Fig.1)comparedtovolume-initiatedfractures).Surfaceprepa-
ceramics should be compressively stressed in use, although
ration can also lead to the introduction of residual stresses.
engineering applications may frequently introduce tensile
Universal or standardized test methods of surface preparation
stresses in the component. Nonetheless, compressive behavior
donotexist.Itshouldbeunderstoodthatfinalmachiningsteps
is an important aspect of mechanical properties and perfor-
may or may not negate machining damage introduced during
mance.Although tensile strength distributions of ceramics are
the initial machining. Note that final compressive fracture of
probabilistic and can be described by a weakest-link failure
theory,suchdescriptionshavebeenshowntobeinapplicableto
compressive strength distributions in at least one study (1).
However, the need to test a statistically significant number of
compressive test specimens is not obviated. Therefore, a
sufficient number of test specimens at each testing condition is
required for statistical analysis and design.
4.3 Compression tests provide information on the strength
and deformation of materials under uniaxial compressive
stresses. Uniform stress states are required to effectively
evaluate any nonlinear stress-strain behavior which may de-
velop as the result of cumulative damage processes (for
example, microcracking) which may be influenced by testing
mode, testing rate, processing or compositional effects,
microstructure, or environmental influences.
4.4 The results of compression tests of test specimens
fabricated to standardized dimensions from a particular mate-
rial or selected portions of a part, or both, may not totally
The boldface numbers in parenthesis refer to the list of references at the end of FIG. 1 Schematic Diagram of One Possible Apparatus for Con-
this test method ducting a Uniaxially Loaded Compression Test
C1424 − 15 (2019)
advanced ceramics can be attributed to the interaction of large example, platens) attached to the test machine, and (2) loading
numbersofmicrocracksthataregeneratedinthevolumeofthe blockswhicharenon-fixedandactastheinterfacebetweenthe
materialandultimatelyleadtolossofstructuralintegrity (1, 2). compression platens and the test specimen. An assembly
Therefore, although surface roughness in the gage section of drawing of such a fixture and a test specimen is shown in Fig.
the test specimen is not as critical for determining maximum 2. The brittle nature of advanced ceramics requires a uniform
strength potential as it is for flexure or tension tests of interface between the loading fixtures and the test specimen.
advanced ceramics, test specimen fabrication history may play Line or point contact stresses lead to crack initiation and
an important role in the measured compressive strength distri- fracture of the test specimen at stresses less than the actual
butions and should be reported. In addition, the nature of compressive strength (that is, where actual strength is the
fabrication used for certain advanced ceramics (for example, intrinsic strength of the material not influenced by the test or
pressureless sintering, hot pressing) may require the testing of test conditions). In addition, large mismatches of Poisson’s
testspecimenswithgagesectionsintheas-processedcondition ratios or elastic moduli between the loading fixture and test
(that is, it may not be possible or desired/required to machine specimen, or both, can introduce lateral tensile forces leading
some test specimen surfaces not directly in contact with test tosplittingofthecompressiontestspecimen.Similarly,plastic
fixture components). For very rough or wavy as-processed deformationoftheloadfixturecaninducelateraltensileforces
surfaces, eccentricities in the stress state due to nonsymmetric with the same effect.
cross sections as well as variation in the cross-sectional 6.2.1.1 Hardened (>48 HR ) steel compression platens shall
c
dimensions may also interfere with the compressive strength be greater in diameter (≥25.4 mm) than the loading blocks and
measurement. Finally, close geometric tolerances, particularly shall be at least 25.4 mm in thickness. The loading surfaces of
in regard to flatness, concentricity, and cylindricity of test the compression platens shall be flat to 0.005 mm. In addition,
specimen surfaces or geometric entities in contact with the test the two loading surfaces (loading face used to contact the
fixture components), are critical requirements for successful loading blocks and bolted face used to attach the platen to the
compression tests. test machine) shall be parallel to 0.005 mm. When installed in
the test machine, the loading surfaces of the upper and lower
5.3 Bending in uniaxial compression tests can introduce
compression platens shall be parallel to each other within
eccentricity, leading to geometric instability of the test speci-
0.01mm and perpendicular to the load line of the test machine
men and buckling failure before valid compressive strength is
to within 0.01 mm (2). The upper and lower compression
attained.Inaddition,ifdeformationsorstrainsaremeasuredat
surfaces where maximum or minimum stresses occur, bending
mayintroduceoverorundermeasurementofstrainsdepending
on the location of the strain-measuring device on the test
specimen.
5.4 Fractures that initiate outside the uniformly stressed
gage section or splitting of the test specimen along its
longitudinal centerline may be due to factors such as stress
concentrations or geometrical transitions, extraneous stresses
introduced by the load fixtures, misalignment of the test
specimen/loading blocks, nonflat loading blocks or nonflat test
specimen ends, or both, or strength-limiting features in the
microstructure of the test specimen. Such non-gage section
fractures will normally constitute invalid tests.
6. Apparatus
6.1 Testing Machines—Machinesusedforcompressiontest-
ing shall conform to the requirements of Practices E4. The
forces used in determining compressive strength shall be
accurate within 61% at any force within the selected force
range of the testing machine as defined in Practices E4.A
schematicshowingpertinentfeaturesofonepossiblecompres-
sive testing apparatus is shown in Fig. 1. Check that the
expectedbreakingforceforthedesiredtestspecimengeometry
and test material is within the capacity of the test machine and
force transducer. Advanced ceramic compression test speci-
mensrequiremuchgreaterforcestofracturethanthoseusually
encountered in tension or flexure test specimens of the same
material.
6.2 Loading Fixtures:
6.2.1 General—Compression loading fixtures are generally
FIG. 2 Example of Basic Fixturing and Test Specimen for Com-
composedoftwoparts:(1)basicsteelcompressionfixtures(for pression Testing
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.