ASTM E1461-07
(Test Method)Standard Test Method for Thermal Diffusivity by the Flash Method
Standard Test Method for Thermal Diffusivity by the Flash Method
SIGNIFICANCE AND USE
Thermal diffusivity is an important property, required for such purposes under transient heat flow conditions, such as design applications, determination of safe operating temperature, process control, and quality assurance.
The flash method is used to measure values of thermal diffusivity, α, of a wide range of solid materials. It is particularly advantageous because of simple specimen geometry, small specimen size requirements, rapidity of measurement and ease of handling..
Under certain strict conditions, specific heat capacity of a homogeneous isotropic opaque solid sample can be determined when the method is used in a quantitative fashion (see Appendix X2).
Thermal diffusivity results, together with related values of specific heat capacity (Cp) and density (ρ) values, can be used in many cases to derive thermal conductivity (λ), according to the relationship:
SCOPE
1.1 This test method covers the determination of the thermal diffusivity of primarily homogeneous isotropic solid materials. Thermal diffusivity values ranging from 10-7 to 10-3 m2/s are measurable by this test method from about 75 to 2800 K.
1.2 This test method is a more detailed form of Test Method C 714, having applicability to much wider ranges of materials, applications, and temperatures, with improved accuracy of measurements.
1.3 This test method is intended to allow a wide variety of apparatus designs. It is not practical in a test method of this type to establish details of construction and procedures to cover all contingencies that might offer difficulties to a person without pertinent technical knowledge, or to stop or restrict research and development for improvements in the basic technique.
1.4 This test method is applicable to the measurements performed on essentially fully dense (preferably, but low porosity would be acceptable), homogeneeous, and isotropic solid materials that are opaque to the specimen of applied energy pulse. Experience has shown, however, that some deviation from these strict guidelines can be accommodated with care and proper experimental design, substantially broadening the usefulness of the method.
1.5 This test method can be considered an absolute (or primary) method of measurement, since no reference standards are required. It is advisable to use reference materials to verify the performance of the instrument used.
1.6 The values stated in SI units are to be regarded as the standard.
1.7 For systems employing lasers as power sources, it is imperative that the safety requirement be fully met..
1.8 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:E1461–07
Standard Test Method for
1
Thermal Diffusivity by the Flash Method
This standard is issued under the fixed designation E1461; 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
2
1.1 Thistestmethodcoversthedeterminationofthethermal 2.1 ASTM Standards:
diffusivity of primarily homogeneous isotropic solid materials. C714 Test Method for Thermal Diffusivity of Carbon and
-7 -3 2
Thermal diffusivity values ranging from 10 to 10 m /s are Graphite by Thermal Pulse Method
measurable by this test method from about 75 to 2800K. E228 Test Method for Linear Thermal Expansion of Solid
1.2 ThistestmethodisamoredetailedformofTestMethod Materials With a Push-Rod Dilatometer
C714, having applicability to much wider ranges of materials,
3. Terminology
applications, and temperatures, with improved accuracy of
3.1 Definitions of Terms Specific to This Standard:
measurements.
1.3 This test method is intended to allow a wide variety of 3.1.1 thermal conductivity, l, of a solid material—the time
rate of steady heat flow through unit thickness of an infinite
apparatus designs. It is not practical in a test method of this
typetoestablishdetailsofconstructionandprocedurestocover slab of a homogeneous material in a direction perpendicular to
the surface, induced by unit temperature difference. The
all contingencies that might offer difficulties to a person
without pertinent technical knowledge, or to stop or restrict property must be identified with a specific mean temperature,
since it varies with temperature.
research and development for improvements in the basic
technique. 3.1.2 thermal diffusivity, a, of a solid material—the prop-
erty given by the thermal conductivity divided by the product
1.4 This test method is applicable to the measurements
performed on essentially fully dense (preferably, but low of the density and heat capacity per unit mass.
3.2 Description of Symbols and Units Specific to This
porosity would be acceptable), homogeneeous, and isotropic
solid materials that are opaque to the specimen of applied Standard:
3.2.1 D—diameter, meters.
energy pulse. Experience has shown, however, that some
deviation from these strict guidelines can be accommodated 3.2.2 C —specific heat capacity, J/(kg·K).
p
3.2.3 k—constant depending on percent rise.
with care and proper experimental design, substantially broad-
3.2.4 K—correction factors.
ening the usefulness of the method.
1.5 This test method can be considered an absolute (or 3.2.5 K,K —constants depending on b.
1 2
3.2.6 L—specimen thickness, m.
primary)methodofmeasurement,sincenoreferencestandards
are required. It is advisable to use reference materials to verify 3.2.7 t—response time, s.
1
3.2.8 t ⁄2 —half-rise time or time required for the rear face
the performance of the instrument used.
1.6 The values stated in SI units are to be regarded as temperature rise to reach one half of its maximum value, s.
2
3.2.9 t*—dimensionless time (t*=4a t/D ).
standard. No other units of measurement are included in this
s T
standard. 3.2.10 T—temperature, K.
2
3.2.11 a—thermal diffusivity, m /s.
1.7 For systems employing lasers as power sources, it is
imperative that the safety requirement be fully met. 3.2.12 b—fraction of pulse duration required to reach
maximum intensity.
1.8 This standard does not purport to address all of the
3
safety concerns, if any, associated with its use. It is the 3.2.13 r—density, kg/m .
3.2.14 l—thermal conductivity, W/m·K.
responsibility of the user of this standard to establish appro-
1 1
priate safety and health practices and determine the applica- 3.2.15 Dt —T (5t ⁄2)/T (t ⁄2 ).
5
1 1
3.2.16 Dt —T (10t ⁄2)/T (t ⁄2 ).
bility of regulatory limitations prior to use.
10
3.2.17 DT —temperaturedifferencebetweenbaselineand
max
maximum rise, K.
1
ThistestmethodisunderthejurisdictionofASTMCommitteeE37onThermal
Measurements and is the direct responsibility of Subcommittee E37.05 onThermo-
2
physical Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2007. Published January 2008. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1992. Last previous edition approved in 2001 as E1461–01. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E1461-07. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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E1461–07
3.3 Description
...
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:E1461–01 Designation:E1461–07
Standard Test Method for
1
Thermal Diffusivity by the Flash Method
This standard is issued under the fixed designation E1461; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of the thermal diffusivity of primarily homogeneous isotropic solid materials.
-7 -3 2
Thermal diffusivity values ranging from 10 to 10 m /s are readily measurable by this test method from about 75 to 2800K.
1.2 This test method is a more detailed form of Test Method C714, but has applicability to much wider ranges of materials,
applications, and temperatures, with improved accuracy of measurements.
1.3This test method is applicable to the measurements performed on materials opaque to the spectrum of the energy pulse, but
with special precautions can be used on fully or partially transparent materials (see Appendix X1).
1.4This test method is intended to allow a wide variety of apparatus designs. It is not practical in a test method of this type to
establishdetailsofconstructionandprocedurestocoverallcontingenciesthatmightofferdifficultiestoapersonwithoutpertinent
technical knowledge, or to stop or restrict research and development for improvements in the basic technique.
1.5This test method is applicable to the measurements performed on essentially fully dense materials; however, in some cases
it has shown to produce acceptable results when used with porous samples. Since the magnitude of porosity, pore shapes, sizes
and parameters of pore distribution influence the behavior of the thermal diffusivity, extreme caution must be exercised when
analyzingdata.Specialcautionisadvisedwhenotherproperties,suchasthermalconductivity,arederivedfromthermaldiffusivity
obtained by this method.
1.6This test method can be considered an absolute (or primary) method of measurement, since no reference standards are
required. It is advisable to use reference materials to verify the performance of the instrument used.
1.7This method is applicable only for homogeneous solid materials, in the strictest sense; however, in some cases it has shown
to produce data which may be useful in certain applications.
1.7.1Testing of Composite Materials—When substantial inhomogeneity and anisotropy is present in a material, the thermal
diffusivity data obtained with this method may be substantially in error. Nevertheless, such data, while usually lacking absolute
accuracy, may be useful in comparing materials of similar structure. Extreme caution must be exercised when related properties,
such as thermal conductivity, are derived, as composites may have heat flow patterns substantially different than uniaxial.
1.7.2Testing Liquids—This method has found an especially useful application in determining thermal diffusivity of molten
materials. For this technique, specially constructed sample enclosures must be used.
1.7.3Testing Layered Materials—This method has also been extended to test certain layered structures made of dissimilar
materials, where one of the layers is considered unknown. In some cases, contact conductance of the interface may also be
determined.
1.8The values stated in SI units are to be regarded as the standard.
1.9This 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. , having applicability to much wider ranges of materials, applications, and temperatures, with improved
accuracy of measurements.
1.3 This test method is intended to allow a wide variety of apparatus designs. It is not practical in a test method of this type
to establish details of construction and procedures to cover all contingencies that might offer difficulties to a person without
pertinent technical knowledge, or to stop or restrict research and development for improvements in the basic technique.
1.4 Thistestmethodisapplicabletothemeasurementsperformedonessentiallyfullydense(preferably,butlowporositywould
be acceptable), homogeneeous, and isotropic solid materials that are opaque to the specimen of applied energy pulse. Experience
has shown, however, that some deviation from these strict guid
...
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