ASTM C1525-04(2009)
(Test Method)Standard Test Method for Determination of Thermal Shock Resistance for Advanced Ceramics by Water Quenching
Standard Test Method for Determination of Thermal Shock Resistance for Advanced Ceramics by Water Quenching
SIGNIFICANCE AND USE
The high temperature capabilities of advanced ceramics are a key performance benefit for many demanding engineering applications. In many of those applications, advanced ceramics will have to perform across a broad temperature range with exposure to sudden changes in temperature and heat flux. Thermal shock resistance of the ceramic material is a critical factor in determining the durability of the component under transient thermal conditions.
This test method is useful for material development, quality assurance, characterization, and assessment of durability. It has limited value for design data generation, because of the limitations of the flexural test geometry in determining fundamental tensile properties.
Appendix X1 (following EN 820-3) provides an introduction to thermal stresses, thermal shock, and critical material/geometry factors. The appendix also contains a mathematical analysis of the stresses developed by thermal expansion under steady state and transient conditions, as determined by mechanical properties, thermal characteristics, and heat transfer effects.
SCOPE
1.1 This test method describes the determination of the resistance of advanced ceramics to thermal shock by water quenching. The method builds on the experimental principle of rapid quenching of a test specimen at an elevated temperature in a water bath at room temperature. The effect of the thermal shock is assessed by measuring the reduction in flexural strength produced by rapid quenching of test specimens heated across a range of temperatures. For a quantitative measurement of thermal shock resistance, a critical temperature interval is determined by a reduction in the mean flexural strength of at least 30 %. The test method does not determine thermal stresses developed as a result of a steady state temperature differences within a ceramic body or of thermal expansion mismatch between joined bodies. The test method is not intended to determine the resistance of a ceramic material to repeated shocks. Since the determination of the thermal shock resistance is performed by evaluating retained strength, the method is not suitable for ceramic components; however, test specimens cut from components may be used.
1.2 The test method is intended primarily for dense monolithic ceramics, but may also be applicable to certain composites such as whisker- or particulate-reinforced ceramic matrix composites that are macroscopically homogeneous.
1.3 Values expressed in this standard test method are in accordance with the International System of Units (SI) and Standard 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: C1525 − 04(Reapproved 2009)
Standard Test Method for
Determination of Thermal Shock Resistance for Advanced
Ceramics by Water Quenching
This standard is issued under the fixed designation C1525; 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 2. Referenced Documents
1.1 This test method describes the determination of the 2.1 ASTM Standards:
resistance of advanced ceramics to thermal shock by water C373Test Method for Water Absorption, Bulk Density,
quenching.Themethodbuildsontheexperimentalprincipleof ApparentPorosity,andApparentSpecificGravityofFired
rapid quenching of a test specimen at an elevated temperature Whiteware Products
in a water bath at room temperature. The effect of the thermal C1145Terminology of Advanced Ceramics
shock is assessed by measuring the reduction in flexural C1161Test Method for Flexural Strength of Advanced
strengthproducedbyrapidquenchingoftestspecimensheated Ceramics at Ambient Temperature
acrossarangeoftemperatures.Foraquantitativemeasurement C1239Practice for Reporting Uniaxial Strength Data and
of thermal shock resistance, a critical temperature interval is Estimating Weibull Distribution Parameters forAdvanced
determined by a reduction in the mean flexural strength of at Ceramics
least 30%. The test method does not determine thermal C1322Practice for Fractography and Characterization of
stresses developed as a result of a steady state temperature Fracture Origins in Advanced Ceramics
differences within a ceramic body or of thermal expansion E4Practices for Force Verification of Testing Machines
mismatch between joined bodies. The test method is not E6Terminology Relating to Methods of MechanicalTesting
intended to determine the resistance of a ceramic material to E616Terminology Relating to Fracture Testing (Discontin-
repeated shocks. Since the determination of the thermal shock ued 1996) (Withdrawn 1996)
resistance is performed by evaluating retained strength, the IEEE/ASTM SI 10Standard for Use of the International
method is not suitable for ceramic components; however, test System of Units (SI): The Modern Metric System
specimens cut from components may be used.
2.2 European Standard:
1.2 The test method is intended primarily for dense mono- EN 820-3 Advanced Technical Ceramics—Monolithic
Ceramics—Thermomechanical Properties—Part 3: Deter-
lithic ceramics, but may also be applicable to certain compos-
mination of Resistance to Thermal Shock by Water
ites such as whisker- or particulate-reinforced ceramic matrix
Quenching
composites that are macroscopically homogeneous.
1.3 Values expressed in this standard test method are in
3. Terminology
accordance with the International System of Units (SI) and
3.1 Definitions:
Standard IEEE/ASTM SI 10.
3.1.1 The terms described inTerminologies C1145, E6, and
1.4 This standard does not purport to address all of the
E616areapplicabletothisstandardtestmethod.Specificterms
safety concerns, if any, associated with its use. It is the
relevant to this test method are as follows:
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
This test method is under the jurisdiction of ASTM Committee C28 on Standards volume information, refer to the standard’s Document Summary page on
Advanced Ceramics and is the direct responsibility of Subcommittee C28.01 on the ASTM website.
Mechanical Properties and Performance. The last approved version of this historical standard is referenced on
Current edition approved July 1, 2009. Published September 2009. Originally www.astm.org.
approved in 2002. Last previous edition approved in 2004 as C1525-04. DOI: Available from European Committee for Standardization (CEN), 36 rue de
10.1520/C1525-04R09. Stassart, B-1050, Brussels, Belgium, http://www.cenorm.be.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1525 − 04 (2009)
3.1.2 advanced ceramic, n—a highly engineered, high per- 5.3 Appendix X1 (following EN 820-3) provides an intro-
formance, predominately non-metallic, inorganic, ceramic ma- duction to thermal stresses, thermal shock, and critical
terial having specific functional attributes. C1145 material/geometry factors. The appendix also contains a math-
ematical analysis of the stresses developed by thermal expan-
3.1.3 critical temperature difference, ∆T,n—temperature
c
sion under steady state and transient conditions, as determined
difference between the furnace and the ambient temperature
by mechanical properties, thermal characteristics, and heat
water bath that will cause a 30% drop in the average flexural
transfer effects.
strength.
3.1.4 flexural strength, σ,n—a measure of the ultimate
6. Interferences
f
strengthofaspecifiedbeamspecimeninbendingdeterminedat
6.1 Time-dependent phenomena such as stress corrosion or
a given stress rate in a particular environment.
slow crack growth may influence the strength tests.This might
3.1.5 fracture toughness, n—a generic term for measures of
especially be a problem if the test specimens are not properly
resistance to extension of a crack. E616
dried before strength testing.
3.1.6 slow crack growth (SCG), n—subcriticalcrackgrowth 6.2 Surface preparation of test specimens can introduce
(extension)whichmayresultfrom,butisnotrestrictedto,such
machining flaws which may have a pronounced effect on the
mechanisms as environmentally-assisted stress corrosion or measured flexural strength. The surface preparation may also
diffusive crack growth.
influence the cracking process due to the thermal shock
procedure. It is especially important to consider surface con-
3.1.7 thermal shock, n—a large and rapid temperature
ditions in comparing test specimens and components.
change, resulting in large temperature differences within or
across a body. C1145 6.3 The results are given in terms of a temperature differ-
ence between furnace and quenching bath (∆T). However, it is
3.1.8 thermal shock resistance, n—thecapabilityofmaterial
important to notice that results may be different for the same
to retain its mechanical properties after exposure to one or
∆T but different absolute temperatures. It is therefore specified
more thermal shocks.
in this test method to quench to room temperature.
6.4 Theformulaepresentedinthistestmethodapplystrictly
4. Summary of Test Method
onlytomaterialsthatdonotexhibit R-curvebehavior,buthave
4.1 This test method indicates the ability of an advanced
a single-valued fracture toughness. If the test material exhibits
ceramic product to withstand the stress generated by sudden
a strong R-curve behavior, i.e., increase in fracture toughness
changes in temperature (thermal shock). The thermal shock
with increasing crack length, caution must be taken in inter-
resistance is measured by determining the loss of strength (as
preting the results.
comparedtoas-receivedspecimens)forceramictestspecimens
6.5 Test data for specimens of different geometries are not
quicklycooledafterathermalexposure.Aseriesofrectangular
directly comparable because of the effect of geometry on heat
or cylindrical test specimen sets are heated across a range of
transfer and stress gradients. Quantitative comparisons of
different temperatures and then quenched rapidly in a water
thermal shock resistance for different ceramic compositions
bath.After quenching, the test specimens are tested in flexure,
should be done with equivalent test specimen geometries.
and the average retained flexural strength is determined for
eachsetofspecimensquenchedfromagiventemperature.The
7. Apparatus
“critical temperature difference” for thermal shock is estab-
lished from the temperature difference (exposure temperature 7.1 Test Apparatus:
minus the water quench temperature) that produces a 30% 7.1.1 The test method requires a thermal exposure/
reduction in flexural strength compared to the average flexural quenching system (consisting of a furnace, specimen handling
strength of the as-received test specimens. equipment, and a quench bath) and a testing apparatus suitable
for measuring the flexural strength of the test specimens.
7.1.2 The test method requires a furnace capable of heating
5. Significance and Use
and maintaining a set of test specimens at the required
5.1 The high temperature capabilities of advanced ceramics
temperature to 65K(6 5°C). The temperature shall be
areakeyperformancebenefitformanydemandingengineering
measured with suitable thermocouples located no more than 2
applications.Inmanyofthoseapplications,advancedceramics
mm from the midpoint of the specimen(s) in the furnace.
will have to perform across a broad temperature range with
Furnaces will usually have an open atmosphere, because air
exposure to sudden changes in temperature and heat flux.
exposure is common during the transfer to the quench bath.
Thermal shock resistance of the ceramic material is a critical
NOTE1—Ifairexposureisdetrimental,aspecialfurnace-quenchsystem
factor in determining the durability of the component under
can be set up in which both the furnace and the quench unit are contained
transient thermal conditions.
withinaninertatmospherecontainer.Acommondesignforsuchasystem
consists of a tube furnace positioned vertically above the quench tank, so
5.2 This test method is useful for material development,
that the test specimen drops directly into the tank from the furnace.
quality assurance, characterization, and assessment of durabil-
ity. It has limited value for design data generation, because of 7.1.3 The method requires a test specimen handling equip-
the limitations of the flexural test geometry in determining mentdesignedsothatthetestspecimencanbetransferredfrom
fundamental tensile properties. the furnace to the quenching bath within 5 s.
C1525 − 04 (2009)
NOTE 3—Under some circumstances the edges of prismatic test
7.1.4 A water bath controlled to 293 6 2 K (20°C 6 2°C)
specimens or the ends of cylindrical test specimens may be damaged by
is required. The water bath must have sufficient volume to
spallation during the quench test. These specimens should be discarded
prevent the temperature in the bath from rising more than 5 K
from the batch used for strength testing if the damage will interfere with
(5°C) after test specimen quenching. It is recommended that
the strength test. In any case such spallation must be noted in the report.
the bath be large enough for the test specimens to have cooled
Spallation problems can be alleviated by chamfering sharp edges.
sufficiently before reaching the bottom of the bath, or contain
NOTE 4—The parallelism tolerances on the four longitudinal faces are
0.015 mm for B and C and the cylindricity for A is 0.015 mm.
a screen near the bottom to prevent the test specimens from
resting directly on the bottom of the bath.
8.2 Test Specimen Preparation—Dependingontheintended
7.1.5 The universal test machine used for strength testing in
application of the thermal shock data, one of the four test
this test method shall conform to the requirements of Practice
specimen preparation methods described in Test Method
E4. Specimens may be loaded in any suitable test machine
C1161 may be used:As-Fabricated,Application-Matched Ma-
providedthatuniformtestrates,eitherusingload-controlledor
chining, Customary Procedures, or Standard Procedures.
displacement-controlled mode, can be maintained. The loads
8.3 Handling Precautions—Care shall be exercised in stor-
used in determining flexural strength shall be accurate within
ing and handling of test specimens to avoid the introduction of
6 1.0% at any load within the selected load rate and load
randomandsevereflaws,suchasmightoccuriftestspecimens
range of the test machine as defined in Practice E4.
were allowed to impact or scratch each other.
7.1.6 The configuration and mechanical properties of the
testfixturesshallbeinaccordancewithTestMethodC1161for
8.4 Number of Test Specimens—A minimum of 10 speci-
use with the standard four-point flexure specimens. If larger
mens shall be used to determine as-received strength at room
test pieces (sizes A or C below) are employed, the test fixture
temperature.Aminimum of 30 is required if estimates regard-
shall be scaled accordingly. There are currently no standard
ingtheformofthestrengthdistributionistobedetermined(for
fixtures for testing cylindrical rods in flexure; however, the
exampleaWeibullmodulus).Aminimumof5specimensshall
fixtures to be used shall have the appropriate articulation. Test
be used at each thermal shock temperature. It is recommended
fixtureswithoutappropriatearticulationshallnotbepermitted;
that as ∆T is established, additional 5 specimens be tested at
c
the articulation of the fixture shall meet the requirements
this as well as the adjacent temperature intervals. This will
specified in Test Method C1161.
allow for determination of the mean and standard deviation. If
7.1.7 The method requires a 393 K (120°C) drying oven to
estimates regarding the form of the strength distribution at the
remove moisture from test specimens before (if needed) and
∆T and adjoining temperature intervals are desired (for
c
after quench testing.
example, Weibull analysis) additional specimens must be
7.1.8 A micrometer with a resolution of 0.002 mm (or
tested at these temperature intervals. See Practice C1239 for
0.0001 in.) or smaller should be used to measure the test piece
guidance on estimating Weibull parameters.
dimensions. The micrometer shall have flat anvil faces. The
micrometer shall not have a ball tip or sharp tip since these
9. Procedure
might damage the test piece if the specimen dimensions are
measured prior to fracture. Alternative dimension measuring 9.1 Test Exposure Temperatures:
instruments may be used provided that they have a resolution
9.1.1 The maximum exposure target temperature of the
of 0.002 mm (or 0.0001 in.) or finer and do no harm to the
furnaceforthethermalshocktestofagivenadvancedceramic
specimen.
will be determined from the maximum performance tempera-
ture required for a specific application, specified in a compara-
8. Test Specimens
tive thermal shock test, or cited in test literature.
9.1.2 The initial exposure temperature can be determined
8.1 The ceramic test specimens shall be pieces specifically
from literature values
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:C1525–03 Designation: C 1525 – 04 (Reapproved 2009)
Standard Test Method for
Determination of Thermal Shock Resistance for Advanced
Ceramics by Water Quenching
This standard is issued under the fixed designation C 1525; 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
1.1 This test method describes the determination of the resistance of advanced ceramics to thermal shock by water quenching.
The method builds on the experimental principle of rapid quenching of a test specimen at an elevated temperature in a water bath
at room temperature.The effect of the thermal shock is assessed by measuring the reduction in flexural strength produced by rapid
quenching of test specimens heated across a range of temperatures. For a quantitative measurement of thermal shock resistance,
a critical temperature interval is determined by a reduction in the mean flexural strength of at least 30 %. The test method does
not determine thermal stresses developed as a result of a steady state temperature differences within a ceramic body or of thermal
expansion mismatch between joined bodies. The test method is not intended to determine the resistance of a ceramic material to
repeated shocks. Since the determination of the thermal shock resistance is performed by evaluating retained strength, the method
is not suitable for ceramic components; however, test specimens cut from components may be used.
1.2 The test method is intended primarily for dense monolithic ceramics, but may also be applicable to certain composites such
as whisker- or particulate-reinforced ceramic matrix composites that are macroscopically homogeneous.
1.3 Values expressed in this standard test method are in accordance with the International System of Units (SI) and Standard
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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards: ASTM Standards:
C 373 Test Method for WaterAbsorption, Bulk Density,Apparent Porosity, andApparent Specific Gravity of Fired Whiteware
Products
C 1145 Terminology of Advanced Ceramics
C 1161 Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature
C 1239 Practice for Reporting Uniaxial Strength Data and Estimating Weibull Distribution Parameters forAdvanced Ceramics
C 1322 Practice for Fractography and Characterization of Fracture Origins in Advanced Ceramics
E4 Practices for Force Verification of Testing Machines
E6 Terminology Relating to Methods of Mechanical Testing
E 616 Terminology Relating to Fracture Testing (Discontinued 1996)
IEEE/ASTM SI 10 Standard for Use of the International System of Units (SI): The Modern Metric System
2.2 European Standard:
EN 820-3 Advanced Technical Ceramics—Monolithic Ceramics—Thermomechanical Properties—Part 3: Determination of
Resistance to Thermal Shock by Water Quenching
3. Terminology
3.1 Definitions—The terms described in Terminologies C 1145, E 6, and E 616 are applicable to this standard test method.
Specific terms relevant to this test method are as follows:
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.
Current edition approved May 10, 2003.July 1, 2009. Published July 2003.September 2009. Originally approved in 2002. Last previous edition approved in 20022004 as
C 1525 - 024.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 15.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
Annual Book of ASTM Standards, Vol 03.01
Available from European Committee for Standardization (CEN), 36 rue de Stassart, B-1050, Brussels, Belgium, http://www.cenorm.be.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1525 – 04 (2009)
3.1.1 advanced ceramic, n—a highly engineered, high performance, predominately non-metallic, inorganic, ceramic material
having specific functional attributes. C 1145
3.1.2 critical temperature difference, DT , n—temperature difference between the furnace and the ambient temperature water
c
bath that will cause a 30 % drop in the average flexural strength.
3.1.3 flexural strength, s, n—a measure of the ultimate strength of a specified beam specimen in bending determined at a given
f
stress rate in a particular environment.
3.1.4 fracture toughness, n—a generic term for measures of resistance to extension of a crack. E 616
3.1.5 slow crack growth (SCG), n—subcritical crack growth (extension) which may result from, but is not restricted to, such
mechanisms as environmentally-assisted stress corrosion or diffusive crack growth.
3.1.6 thermal shock, n—alargeandrapidtemperaturechange,resultinginlargetemperaturedifferenceswithinoracrossabody.
C 1145
3.1.7 thermal shock resistance, n—the capability of material to retain its mechanical properties after exposure to one or more
thermal shocks.
4. Summary of Test Method
4.1 This test method indicates the ability of an advanced ceramic product to withstand the stress generated by sudden changes
in temperature (thermal shock). The thermal shock resistance is measured by determining the loss of strength (as compared to
as-received specimens) for ceramic test specimens quickly cooled after a thermal exposure. A series of rectangular or cylindrical
test specimen sets are heated across a range of different temperatures and then quenched rapidly in a water bath.After quenching,
thetestspecimensaretestedinflexure,andtheaverageretainedflexuralstrengthisdeterminedforeachsetofspecimensquenched
from a given temperature. The “critical temperature difference” for thermal shock is established from the temperature difference
(exposure temperature minus the water quench temperature) that produces a 30 % reduction in flexural strength compared to the
average flexural strength of the as-received test specimens.
5. Significance and Use
5.1 The high temperature capabilities of advanced ceramics are a key performance benefit for many demanding engineering
applications. In many of those applications, advanced ceramics will have to perform across a broad temperature range with
exposure to sudden changes in temperature and heat flux. Thermal shock resistance of the ceramic material is a critical factor in
determining the durability of the component under transient thermal conditions.
5.2 This test method is useful for material development, quality assurance, characterization, and assessment of durability. It has
limitedvaluefordesigndatageneration,becauseofthelimitationsoftheflexuraltestgeometryindeterminingfundamentaltensile
properties.
5.3 Appendix X1 (following EN 820-3) provides an introduction to thermal stresses, thermal shock, and critical material/
geometryfactors.Theappendixalsocontainsamathematicalanalysisofthestressesdevelopedbythermalexpansionundersteady
state and transient conditions, as determined by mechanical properties, thermal characteristics, and heat transfer effects.
6. Interferences
6.1 Time-dependent phenomena such as stress corrosion or slow crack growth may influence the strength tests. This might
especially be a problem if the test specimens are not properly dried before strength testing.
6.2 Surface preparation of test specimens can introduce machining flaws which may have a pronounced effect on the measured
flexural strength. The surface preparation may also influence the cracking process due to the thermal shock procedure. It is
especially important to consider surface conditions in comparing test specimens and components.
6.3 The results are given in terms of a temperature difference between furnace and quenching bath (DT). However, it is
important to notice that results may be different for the same DT but different absolute temperatures. It is therefore specified in
this test method to quench to room temperature.
6.4 The formulae presented in this test method apply strictly only to materials that do not exhibit R-curve behavior, but have
a single-valued fracture toughness. If the test material exhibits a strong R-curve behavior, i.e., increase in fracture toughness with
increasing crack length, caution must be taken in interpreting the results.
6.5 Testdataforspecimensofdifferentgeometriesarenotdirectlycomparablebecauseoftheeffectofgeometryonheattransfer
and stress gradients. Quantitative comparisons of thermal shock resistance for different ceramic compositions should be done with
equivalent test specimen geometries.
7. Apparatus
7.1 Test Apparatus:
7.1.1 The test method requires a thermal exposure/quenching system (consisting of a furnace, specimen handling equipment,
and a quench bath) and a testing apparatus suitable for measuring the flexural strength of the test specimens.
7.1.2 The test method requires a furnace capable of heating and maintaining a set of test specimens at the required temperature
to 65K(6 5°C). The temperature shall be measured with suitable thermocouples located no more than 2 mm from the midpoint
of the specimen(s) in the furnace. Furnaces will usually have an open atmosphere, because air exposure is common during the
transfer to the quench bath.
C 1525 – 04 (2009)
NOTE 1—If air exposure is detrimental, a special furnace-quench system can be set up in which both the furnace and the quench unit are contained
within an inert atmosphere container.Acommon design for such a system consists of a tube furnace positioned vertically above the quench tank, so that
the test specimen drops directly into the tank from the furnace.
7.1.3 The method requires a test specimen handling equipment designed so that the test specimen can be transferred from the
furnace to the quenching bath within 5 s.
7.1.4 A water bath controlled to 293 6 2 K (20°C 6 2°C) is required. The water bath must have sufficient volume to prevent
the temperature in the bath from rising more than 5 K (5°C) after test specimen quenching. It is recommended that the bath be
large enough for the test specimens to have cooled sufficiently before reaching the bottom of the bath, or contain a screen near the
bottom to prevent the test specimens from resting directly on the bottom of the bath.
7.1.5 The universal test machine used for strength testing in this test method shall conform to the requirements of Practice E 4.
Specimens may be loaded in any suitable test machine provided that uniform test rates, either using load-controlled or
displacement-controlledmode,canbemaintained.Theloadsusedindeterminingflexuralstrengthshallbeaccuratewithin 61.0 %
at any load within the selected load rate and load range of the test machine as defined in Practice E 4.
7.1.6 The configuration and mechanical properties of the test fixtures shall be in accordance with Test Method C 1161 for use
with the standard four-point flexure specimens. If larger test pieces (sizes A or C below) are employed, the test fixture shall be
scaled accordingly. There are currently no standard fixtures for testing cylindrical rods in flexure; however, the fixtures to be used
shall have the appropriate articulation. Test fixtures without appropriate articulation shall not be permitted; the articulation of the
fixture shall meet the requirements specified in Test Method C 1161.
7.1.7 The method requires a 393 K (120°C) drying oven to remove moisture from test specimens before (if needed) and after
quench testing.
7.1.8 A micrometer with a resolution of 0.002 mm (or 0.0001 in.) or smaller should be used to measure the test piece
dimensions. The micrometer shall have flat anvil faces. The micrometer shall not have a ball tip or sharp tip since these might
damagethetestpieceifthespecimendimensionsaremeasuredpriortofracture.Alternativedimensionmeasuringinstrumentsmay
be used provided that they have a resolution of 0.002 mm (or 0.0001 in.) or finer and do no harm to the specimen.
8. Test Specimens
8.1 Theceramictestspecimensshallbepiecesspecificallypreparedforthispurposefrombulkmaterialorcutfromcomponents.
8.1.1 Specimen Size—Three specimen geometries are defined for use in this test method:
8.1.1.1 Type A—Rods 10 6 0.13 mm in diameter, 120 mm long.
8.1.1.2 Type B—Bars 3 6 0.13 mm 3 4 6 0.13 mm in cross section, minimum 45 mm long with chamfered edges, in
accordance with type B in Test Method C 1161.
8.1.1.3 Type C—Bars 10 6 0.13 mm 3 10 6 0.13 mm in cross section, 120 mm long, with chamfered edges.
NOTE 2—The test specimens ofAand C type are intended to be large enough to produce a materials ranking that is basically independent of specimen
size and appropriate for larger test specimens (1, 2). Test specimens of B type may require greater quenching temperature differences in order to produce
strength reduction. These test specimens may not correctly rank the relative behavior of larger components. Only Type B coincides with Type B in Test
Method C 1161. Test specimens of B type may require greater quenching temperature differences in order to produce strength reduction. These test
specimens may not correctly rank the relative behavior of larger components. Only Type B coincides with Type B in Test Method C1161.
NOTE 3—Under some circumstances the edges of prismatic test specimens or the ends of cylindrical test specimens may be damaged by spallation
during the quench test. These specimens should be discarded from the batch used for strength testing if the damage will interfere with the strength test.
In any case such spallation must be noted in the report. Spallation problems can be alleviated by chamfering sharp edges.
NOTE 4—The parallelism tolerances on the four longitudinal faces are 0.015 mm for B and C and the cylindricity for A is 0.015 mm.
8.2 Test Specimen Preparation—Dependingontheintendedapplicationofthethermalshockdata,oneofthefourtestspecimen
preparation methods described in Test Method C 1161 may be used: As-Fabricated, Application-Matched Machining, Cu
...
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