ASTM C1525-04(2013)
(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
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 limited value for design data generation, because of the limitations of the flexural test geometry in determining fundamental tensile properties.
5.3 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 2013)
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, Ceramic Tiles, and Glass Tiles
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 Mechanical Testing
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 Aug. 1, 2013. Published September 2013. Originally www.astm.org.
approved in 2002. Last previous edition approved in 2009 as C1525–04 (2009). Available from European Committee for Standardization (CEN), 36 rue de
DOI: 10.1520/C1525-04R13. 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 (2013)
3.1.2 advanced ceramic, n—a highly engineered, high 5.3 Appendix X1 (following EN 820-3) provides an intro-
performance, predominately non-metallic, inorganic, ceramic duction to thermal stresses, thermal shock, and critical
material 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, that is, increase in fracture tough-
changes in temperature (thermal shock). The thermal shock
ness with increasing crack length, caution must be taken in
resistance is measured by determining the loss of strength (as
interpreting 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 (2013)
ences in order to produce strength reduction. These test specimens may
7.1.4 A water bath controlled to 293 6 2 K (20°C 6 2°C)
not correctly rank the relative behavior of larger components. Only Type
is required. The water bath must have sufficient volume to
B coincides with Type B in Test Method C1161.
prevent the temperature in the bath from rising more than 5 K
NOTE 3—Under some circumstances the edges of prismatic test
(5°C) after test specimen quenching. It is recommended that
specimens or the ends of cylindrical test specimens may be damaged by
the bath be large enough for the test specimens to have cooled
spallation during the quench test. These specimens should be discarded
from the batch used for strength testing if the damage will interfere with
sufficiently before reaching the bottom of the bath, or contain
the strength test. In any case such spallation must be noted in the report.
a screen near the bottom to prevent the test specimens from
Spallation problems can be alleviated by chamfering sharp edges.
resting directly on the bottom of the bath.
NOTE 4—The parallelism tolerances on the four longitudinal faces are
7.1.5 The universal test machine used for strength testing in
0.015 mm for B and C and the cylindricity for A is 0.015 mm.
this test method shall conform to the requirements of Practice
8.2 Test Specimen Preparation—Depending on the intended
E4. Specimens may be loaded in any suitable test machine
application of the thermal shock data, one of the four test
providedthatuniformtestrates,eitherusingload-controlledor
specimen preparation methods described in Test Method
displacement-controlled mode, can be maintained. The loads
C1161 may be used: As-Fabricated, Application-Matched
used in determining flexural strength shall be accurate within
Machining, Customary Procedures, or Standard Procedures.
61.0%atanyloadwithintheselectedloadrateandloadrange
of the test machine as defined in Practice E4. 8.3 Handling Precautions—Care shall be exercised in stor-
ing and handling of test specimens to avoid the introduction of
7.1.6 The configuration and mechanical properties of the
testfixturesshallbeinaccordancewithTestMethodC1161for randomandsevereflaws,suchasmightoccuriftestspecimens
were allowed to impact or scratch each other.
use with the standard four-point flexure specimens. If larger
test pieces (sizes A or C below) are employed, the test fixture
8.4 Number of Test Specimens—A minimum of 10 speci-
shall be scaled accordingly. There are currently no standard
mens shall be used to determine as-received strength at room
fixtures for testing cylindrical rods in flexure; however, the
temperature.Aminimum of 30 is required if estimates regard-
fixtures to be used shall have the appropriate articulation. Test
ingtheformofthestrengthdistributionistobedetermined(for
fixtures without appropriate articulation shall not be permitted;
exampleaWeibullmodulus).Aminimumof5specimensshall
the articulation of the fixture shall meet the requirements
be used at each thermal shock temperature. It is recommended
specified in Test Method C1161.
that as ∆T is established, additional 5 specimens be tested at
c
7.1.7 The method requires a 393 K (120°C) drying oven to
this as well as the adjacent temperature intervals. This will
remove moisture from test specimens before (if needed) and
allow for determination of the mean and standard deviation. If
after quench testing.
estimates regarding the form of the strength distribution at the
7.1.8 A micrometer with a resolution of 0.002 mm (or
∆T and adjoining temperature intervals are desired (for
c
0.0001 in.) or smaller should be used to measure the test piece
example, Weibull analysis) additional specimens must be
dimensions. The micrometer shall have flat anvil faces. The
tested at these temperature intervals. See Practice C1239 for
micrometer shall not have a ball tip or sharp tip since these
guidance on estimating Weibull parameters.
might damage the test piece if the specimen dimensions are
measured prior to fracture. Alternative dimension measuring
9. Procedure
instruments may be used provided that they have a resolution
9.1 Test Exposure Temperatures:
of 0.002 mm (or 0.0001 in.) or finer and do no harm to the
9.1.1 The maximum exposure target temperature of the
specimen.
furnace for the thermal shock test of a given advanced ceramic
8. Test Specimens will be determined from the maximum performance tempera-
ture required for
...
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