ASTM E2092-23

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Designation: E2092 − 18a E2092 − 23
Standard Test Method for
Distortion Temperature in Three-Point Bending by
Thermomechanical Analysis
This standard is issued under the fixed designation E2092; 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 temperature at which the specific modulus of a test specimen is realized
by deflection in three-point bending. This temperature is identified as the distortion temperature. The distortion temperature is that
temperature at which a test specimen of defined geometry deforms to a level of strain under applied stress of 0.455 MPa (66 psi)
(Method A) and 1.82 MPa (264 psi) (264 psi) (Method B) equivalent to those used in Test Method D648. The test is applicable
over the range of temperature from ambient to 300 °C.
NOTE 1—This test method is intended to provide results similar to those of Test Method D648 but is performed on a thermomechanical analyzer using
a smaller test specimen. Equivalence of results to those obtained by Test Method D648 has been demonstrated on a limited number of materials. The
results of this test method shall be considered to be independent and unrelated to those of Test Method D648 unless the user demonstrates equivalence.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
D648 Test Method for Deflection Temperature of Plastics Under Flexural Load in the Edgewise Position
E473 Terminology Relating to Thermal Analysis and Rheology
E1142 Terminology Relating to Thermophysical Properties
E1363 Test Method for Temperature Calibration of Thermomechanical Analyzers
E2113 Test Method for Length Change Calibration of Thermomechanical Analyzers
E2206 Test Method for Force Calibration of Thermomechanical Analyzers
E3142 Test Method for Thermal Lag of Thermal Analysis Apparatus
This test method is under the jurisdiction of Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee E37.10 on Fundamental,
Statistical and Mechanical Properties.
Current edition approved Dec. 1, 2018Nov. 1, 2023. Published January 2019November 2023. Originally approved in 2000. Last previous edition approved in 2018 as
E2092 – 18.E2092 – 18a. DOI: 10.1520/E2092-18A.10.1520/E2092-23.
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
Standardsvolume information, refer tot he standard’s Document Summary page on the ASTM website.
*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
E2092 − 23
3. Terminology
3.1 Definitions—Specific technical terms used in this standard are defined in Terminologies E473 and E1142, including stress,
strain, and thermomechanical analyzer.
3.1.1 distortion temperature [°C], n—the temperature at which an arbitrary strain level is obtained in three-point bending under
an arbitrary load.
4. Summary of Test Method
4.1 A test specimen of known dimensions is tested in three-point bending mode. A known stress is applied to the center of a test
specimen supported near its ends, as it is heated at a constant rate from ambient temperature to the upper temperature limit for the
material. The deflection of the test specimen is recorded as a function of temperature. The temperature at which a predetermined
level of strain is observed in the test specimen is analyzed as the distortion temperature.
5. Significance and Use
5.1 Data obtained by this test method shall not be used to predict the behavior of materials at elevated temperatures except in
applications in which the conditions of time, temperature, method of loading, and stress are similar to those specified in the test.
5.2 This standard is particularly suited for quality control and development work. The data are not intended for use in design or
predicting endurance at elevated temperatures.
6. Apparatus
6.1 A thermomechanical analyzer consisting of:
-1 -1
6.1.1 Rigid Specimen Holder, of inert, low coefficient of expansion material <20 μm m · °C to center the specimen in the
furnace and to fix the specimen to mechanical ground.
-1 -1
6.1.2 Flexure Fixture, of inert, low coefficient of expansion material <20 μm m · °C , to support the test specimen in a
three-point bending mode (see Fig. 1).
-1 -1
6.1.3 Rigid Knife Edge Compression Probe, of inert, low coefficient of expansion material <20 μm m · °C that contacts the
specimen with an applied compression force (see Fig. 1).
6.1.4 Deflection Sensing Element, having a linear output over a minimum range of 5 mm to measure the displacement of the rigid
compression probe (see 6.1.3) to within 60.1 μm.
6.1.5 Programmable Weight or Force Transducer, to generate a constant force (62.5 %) between at least 0.01 N to 1.0 N, that
is applied to the specimen through the rigid compression probe (see 6.1.3).
6.1.6 Temperature Sensor, that can be positioned reproducibly in close proximity to the specimen to measure its temperature within
the range between 25 °C and 300 °C readable to 6 0.1 60.1 °C.
6.1.7 Temperature Programmer and Furnace, capable of temperature programming the test specimen from ambient to 300 °C at
a linear rate of at least 22 °C ⁄min 6 0.1 °C/min.
6.1.8 Means of Providing a Specimen Environment, of inert gas at a purge rate of 50 mL/min 6 5 %.
NOTE 2—Typically, inert purge gases that inhibit specimen oxidation are 99.9+ % pure nitrogen, helium or argon. Dry gases are recommended for all
experiments unless the effect of moisture is part of the study. The purge gas used for the test specimen shall be the same as that used during calibration.
6.1.9 Data Collection Device, to provide a means of acquiring, storing, and displaying measured or calculated signals, or both.
The minimum output signals required for a thermomechanical analyzer are dimension ion change, temperature and time.
6.1.10 While not required, it is convenient to have a data analysis device, that will perform and display the calculations of this
standard.
E2092 − 23
FIG. 1 Flexure Support Geometry
6.2 Micrometer, calipers, film gage or other length-measuring device capable of measuring lengths of 0.01 mm to 20 mm readable
to within 60.001 mm.
7. Hazards
7.1 Toxic or corrosive effluents, or both, may be released when heating some materials and could be harmful to personnel and to
apparatus.
7.2 Because the specimen size is small, care must be taken to ensure that each specimen is homogeneous and representative of
the sample as a whole.
8. Sampling
8.1 The specimens may be cut from sheets, plates, or molded shapes, or may be molded to the desired finished dimensions.
8.2 The specimens used in this test method are ordinarily in the form of rectangular beams with aspect ratios of 1: 3: 10 1:3:10
for thickness or specimen depth (d), width (b) and length (l), depending upon the modulus of the sample and length of the support
span (L).
NOTE 3—Other specimen and support dimensions may be used but care must be taken that the support length to specimen thickness ratio (L/d) be greater
than 10.
NOTE 4—The specimen shall be long enough to allow overhanging on each end of at least 10 % of the support span, that is, l ≥ 1.2 L.
NOTE 5—The overhang shall be sufficient to prevent the specimen from slipping from the supports.
8.3 This test method assumes that the material is isotropic. Should the specimen be anisotropic, such as in reinforced composites,
the direction of the reinforcing agent shall be reported relative to the specimen dimensions.
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9. Calibration
9.1 Calibrate the temperature display of the apparatus according to Test Method E1363 using a heating rate of 2 °C/min 6 0.1
°C/min.
NOTE 6—Temperature calibration shall be performed using the same heating rate as that used for the test specimen (see Appendix X1).
9.2 Calibrate the deflection (length change) display of the apparatus according to the instrument manufacturer’s instructions (see
Test Method E2113).
9.3 Calibrate the mechanism for applying force to the test specimen according to the instrument manufacturer’s instructions (see
Test Method E2206).
NOTE 7—Calibration or calibration verification of all signals at least annually is recommended.
10. Procedure
10.1 Measure the test length (L) of the test specimen as the distance between the two support points of the flexure support
geometry to three significant figures (see Fig. 1).
10.2 Measure the width (b) and thickness (d) of the test specimen to three significant figures (see Fig. 2).
10.3 Select the stress (S) to be applied to the test specimen. This value is typically 0.4550.455 MPa (Method A) or 1.82 MPa
(Method B) to correspond with the values used in Test Method D648.
NOTE 8—Other values may be used but shall be reported.
10.4 Select the strain (r) to be used to identify the heat distortion temperature.
NOTE 9—This value is typically 2.0 mm/m (0.20 %) to correspond with the values used in Test Method D648.
FIG. 2 Test Specimen Geometry
E2092 − 23
10.5 Using Eq 1, calculate to three significant figures the for
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