ASTM E2368-10

Standard Practice for Strain Controlled Thermomechanical Fatigue Testing

SIGNIFICANCE AND USE
In the utilization of structural materials in elevated temperature environments, components that are susceptible to fatigue damage may experience some form of simultaneously varying thermal and mechanical forces throughout a given cycle. These conditions are often of critical concern because they combine temperature dependent and cycle dependent (fatigue) damage mechanisms with varying severity relating to the phase relationship between cyclic temperature and cyclic mechanical strain. Such effects can be found to influence the evolution of microstructure, micromechanisms of degradation, and a variety of other phenomenological processes that ultimately affect cyclic life. The strain-controlled thermomechanical fatigue test is often used to investigate the effects of simultaneously varying thermal and mechanical loadings under idealized conditions, where cyclic theoretically uniform temperature and strain fields are externally imposed and controlled throughout the gage section of the specimen.
SCOPE
1.1 This practice covers the determination of thermomechanical fatigue (TMF) properties of materials under uniaxially loaded strain-controlled conditions. A “thermomechanical” fatigue cycle is here defined as a condition where uniform temperature and strain fields over the specimen gage section are simultaneously varied and independently controlled. This practice is intended to address TMF testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. While this practice is specific to strain-controlled testing, many sections will provide useful information for force-controlled or stress-controlled TMF testing.
1.2 This practice allows for any maximum and minimum values of temperature and mechanical strain, and temperature-mechanical strain phasing, with the restriction being that such parameters remain cyclically constant throughout the duration of the test. No restrictions are placed on environmental factors such as pressure, humidity, environmental medium, and others, provided that they are controlled throughout the test, do not cause loss of or change in specimen dimensions in time, and are detailed in the data report.
1.3 The use of this practice is limited to specimens and does not cover testing of full-scale components, structures, or consumer products.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

General Information

• Status: Historical
• Publication Date: 30-Apr-2010
• ICS: 19.060 - Mechanical testing
• Technical Committee: E08 - Fatigue and Fracture
• Drafting Committee: E08.05 - Cyclic Deformation and Fatigue Crack Formation

Relations

• Replaces: ASTM E2368-04e1 - Standard Practice for Strain Controlled Thermomechanical Fatigue Testing
• Effective Date: 01-May-2010
• Referred By: ASTM F3056-14(2021) - Standard Specification for Additive Manufacturing Nickel Alloy (UNS N06625) with Powder Bed Fusion
• Effective Date: 01-May-2010
• Referred By: ASTM F3055-14a(2021) - Standard Specification for Additive Manufacturing Nickel Alloy (UNS N07718) with Powder Bed Fusion
• Effective Date: 01-May-2010
• Referred By: ASTM F2924-14(2021) - Standard Specification for Additive Manufacturing Titanium-6 Aluminum-4 Vanadium with Powder Bed Fusion
• Effective Date: 01-May-2010
• Referred By: ASTM F3184-16 - Standard Specification for Additive Manufacturing Stainless Steel Alloy (UNS S31603) with Powder Bed Fusion
• Effective Date: 01-May-2010
• Referred By: ASTM F3122-14(2022) - Standard Guide for Evaluating Mechanical Properties of Metal Materials Made via Additive Manufacturing Processes
• Effective Date: 01-May-2010
• Referred By: ASTM E2714-13(2020) - Standard Test Method for Creep-Fatigue Testing
• Effective Date: 01-May-2010
• Referred By: ASTM E3097-23 - Standard Test Method for Uniaxial Constant Force Thermal Cycling of Shape Memory Alloys
• Effective Date: 01-May-2010
• Referred By: ASTM E3098-17 - Standard Test Method for Mechanical Uniaxial Pre-strain and Thermal Free Recovery of Shape Memory Alloys
• Effective Date: 01-May-2010

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E2368 − 10
Standard Practice for
1
Strain Controlled Thermomechanical Fatigue Testing
This standard is issued under the fixed designation E2368; 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 E4 Practices for Force Verification of Testing Machines
E83 Practice for Verification and Classification of Exten-
1.1 This practice covers the determination of thermome-
someter Systems
chanicalfatigue(TMF)propertiesofmaterialsunderuniaxially
E111 Test Method for Young’s Modulus, Tangent Modulus,
loaded strain-controlled conditions. A “thermomechanical”
and Chord Modulus
fatigue cycle is here defined as a condition where uniform
E112 Test Methods for Determining Average Grain Size
temperature and strain fields over the specimen gage section
E220 Test Method for Calibration of Thermocouples By
are simultaneously varied and independently controlled. This
Comparison Techniques
practice is intended to address TMF testing performed in
E337 Test Method for Measuring Humidity with a Psy-
support of such activities as materials research and
chrometer (the Measurement of Wet- and Dry-Bulb Tem-
development, mechanical design, process and quality control,
peratures)
product performance, and failure analysis. While this practice
E467 Practice for Verification of Constant Amplitude Dy-
is specific to strain-controlled testing, many sections will
namic Forces in an Axial Fatigue Testing System
provide useful information for force-controlled or stress-
E606 Test Method for Strain-Controlled Fatigue Testing
controlled TMF testing.
E1012 Practice for Verification of Testing Frame and Speci-
1.2 This practice allows for any maximum and minimum
men Alignment Under Tensile and Compressive Axial
values of temperature and mechanical strain, and temperature-
Force Application
mechanical strain phasing, with the restriction being that such
E1823 TerminologyRelatingtoFatigueandFractureTesting
parameters remain cyclically constant throughout the duration
of the test. No restrictions are placed on environmental factors
3. Terminology
such as pressure, humidity, environmental medium, and others,
3.1 The definitions in this practice are in accordance with
provided that they are controlled throughout the test, do not
definitions given in Terminology E1823 unless otherwise
cause loss of or change in specimen dimensions in time, and
stated.
are detailed in the data report.
3.2 Definitions:
1.3 The use of this practice is limited to specimens and does
3.2.1 Additional definitions are as follows:
not cover testing of full-scale components, structures, or
consumer products. 3.2.2 stress, σ—stressisdefinedhereintobetheengineering
stress, which is the ratio of force, P, to specimen original cross
1.4 The values stated in SI units are to be regarded as
sectional area, A:
standard. No other units of measurement are included in this
standard. σ 5 P/A (1)
The area, A, is that measured in an unloaded condition at
2. Referenced Documents
room temperature. See 7.2 for temperature state implications.
2
2.1 ASTM Standards:
3.2.3 coeffıcient of thermal expansion, α—the fractional
E3 Guide for Preparation of Metallographic Specimens
change in free expansion strain for a unit change in
temperature, as measured on the test specimen.
1
This practice is under the jurisdiction ofASTM Committee E08 on Fatigue and
3.2.4 total strain, ε—the strain component measured on the
t
Fracture and is the direct responsibility of Subcommittee E08.05 on Cyclic
test specimen, and is the sum of the thermal strain and the
Deformation and Fatigue Crack Formation.
Current edition approved May 1, 2010. Published June 2010. Originally mechanical strain.
ε1
approved in 2004. Last previous edition approved in 2004 as E2368–04 . DOI:
3.2.5 thermal strain, ε —the strain component resulting
10.1520/E2368-10. th
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
from a change in temperature under free expansion conditions
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
(as measured on the test specimen).
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. ε 5 α·∆T (2)
th
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E2368 − 10
NOTE 1—For some materials, α may be nonlinear over the temperature
(test frame and associated fixtures) shall be in compliance with
range of interest.
the bending strain criteria specified in Practices E606, E1012,
3.2.6 mechanical strai
...

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.
´1
Designation:E2368–04 Designation:E2368–10
Standard Practice for
1
Strain Controlled Thermomechanical Fatigue Testing
This standard is issued under the fixed designation E2368; 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
´ NOTE—Editorial changes were made throughout in May 2005.
1. Scope
1.1 This practice covers the determination of thermomechanical fatigue (TMF) properties of materials under uniaxially loaded
strain-controlled conditions. A “thermomechanical” fatigue cycle is here defined as a condition where uniform temperature and
strain fields over the specimen gage section are simultaneously varied and independently controlled. This practice is intended to
address TMF testing performed in support of such activities as materials research and development, mechanical design, process
and quality control, product performance, and failure analysis. While this practice is specific to strain-controlled testing, many
sections will provide useful information for force-controlled or stress-controlled TMF testing.
1.2 This practice allows for any maximum and minimum values of temperature and mechanical strain, and temperature-
mechanical strain phasing, with the restriction being that such parameters remain cyclically constant throughout the duration of
the test. No restrictions are placed on environmental factors such as pressure, humidity, environmental medium, and others,
provided that they are controlled throughout the test, do not cause loss of or change in specimen dimensions in time, and are
detailed in the data report.
1.3 The use of this practice is limited to specimens and does not cover testing of full-scale components, structures, or consumer
products.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
2. Referenced Documents
2
2.1 ASTM Standards:
E3 Guide for Preparation of Metallographic Specimens
E4 Practices for Force Verification of Testing Machines
E83 Practice for Verification and Classification of Extensometer Systems
E111 Test Method for Young’s Modulus, Tangent Modulus, and Chord Modulus
E112 Test Methods for Determining Average Grain Size
E220 Test Method for Calibration of Thermocouples By Comparison Techniques
E337 Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)
E467 Practice for Verification of Constant Amplitude Dynamic Forces in an Axial Fatigue Testing System
E606 Practice for Strain-Controlled Fatigue Testing
E739Practice for Statistical Analysis of Linear or Linearized Stress-Life ( S-N) and Strain-Life (-N) Fatigue Data
E1012 PracticeforVerificationofTestFrameandSpecimenAlignmentUnderTensileandCompressiveAxialForceApplication
E1823 Terminology Relating to Fatigue and Fracture Testing
3. Terminology
3.1 The definitions in this practice are in accordance with definitions given in Terminology E1823 unless otherwise stated.
3.2 Additional definitions are as follows:
3.2.1 stress, s—stress is defined herein to be the engineering stress, which is the ratio of force, P, to specimen original cross
sectional area, A:
s5 P/A (1)
1
This practice is under the jurisdiction ofASTM Committee E08 on Fatigue and Fracture and is the direct responsibility of Subcommittee E08.05 on Cyclic Deformation
and Fatigue Crack Formation.
Current edition approved May 1, 2004. Published June 2004. DOI: 10.1520/E2368-04E01.
´1
CurrenteditionapprovedMay1,2010.PublishedJune2010.Originallyapprovedin2004.Lastpreviouseditionapprovedin2004asE2368–04 .DOI:10.1520/E2368-10.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
E2368–10
The area, A, is that measured in an unloaded condition at room temperature. See 7.2 for temperature state implications.
3.2.2 coeffıcient of thermal expansion, a—the fractional change in free expansion strain for a unit change in temperature, as
measured on the test specimen.
3.2.3 total strain, ´—the strain component meas
...