ASTM E3414-23

• Abstract:

  SIGNIFICANCE AND USE; 4.1 Constant torque thermal cycling tests determine the effect of shear stress on the transformation properties such as transformation temperatures, actuation shear strain and residual shear strain of a shape memory alloy. This test is done to provide data for the characterization selection of shape memory alloy materials, quality control, design allowables and actuator design (1-3).5 The tests should be used for one thermal cycle but may be used for repeated thermal cycles as agreed upon between supplier and customer. ; 4.2 Measurement of the specimen's motion closely parallels many shape memory actuator applications and provides a result that is applicable to the function of the material. ; 4.3 This test method may be used for cylindrical specimens such as wire, round tube or bar forms. Thus, it is able to provide an assessment of the product in its semi-finished form. ; 4.4 This test method provides a simple method for determining transformation temperatures by heating and cooling specimens through their full thermal transformation under torque. ; 4.5 This test method may also be used to evaluate partial transformation cycles as set by the LCT and UCT and agreed upon between the user and customer. Examples of partial and full transformation thermal cycles are provided in Fig. 2. ; FIG. 2 Effects of Shear Stress and Upper Cycle Temperature on Test Results ; Note 1: A) UCT sufficient for complete Austenitic transformation. B) UCT not sufficient for complete Austenitic transformation. “τ” is the applied shear stress. ; 4.6 This test method can be used on trained and processed material in a semi-finished form to measure Two Way Shape Memory Effect (TWSME) by comparing the shear strain at the LCT and UCT with a torque set such that the corresponding shear stress shall not exceed 7 MPa. For determining TWSME in this manner it is suggested that a full transformation cycle be performed in accordance with 5.7. ; 4.7 This test method is useful for quality control, sp...; SCOPE; 1.1 This test method will define procedures for thermomechanical cycling of shape memory alloys (SMA) material and components with circular cross-sections under constant torque. This test method will measure the transformation properties such as transformation temperatures, actuation shear strain and residual shear strain, when a shape memory alloy is thermally cycled through the phase transformation under a constant applied torque. This test is done to provide data for the characterization selection of shape memory alloy materials, quality control, design allowables and actuator design. ; 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.

• Status: Published
• Publication Date: 31-Oct-2023
• Technical Committee: E08 - Fatigue and Fracture
• Drafting Committee: E08.05 - Cyclic Deformation and Fatigue Crack Formation

Overview

ASTM E3414-23 is the internationally recognized Standard Test Method for Constant Torque Thermal Cycling of Cylindrical Shape Memory Alloy Specimens. Developed by ASTM International, this method defines reliable procedures for subjecting cylindrical shape memory alloys (SMAs) such as wires, round tubes, or bars to controlled torque during thermal cycling. It is a cornerstone for characterizing transformation properties-such as transformation temperatures, actuation shear strain, and residual shear strain-critical for the development, selection, and quality control of SMA materials in various industries.

The standard addresses the practical need to understand how SMAs behave under shear stress during thermal cycles, closely paralleling real actuator use cases. It supports the characterization and assessment of semi-finished products and feeds valuable data into design and quality assurance processes for SMA components.

Key Topics

• Thermal Cycling Under Constant Torque: Procedures to assess shape memory alloys under shear stress by thermal cycling between defined lower and upper cycle temperatures (LCT, UCT).
• Measurement of Transformation Properties: Determination of transformation temperatures (martensite start/finish, austenite start/finish), actuation, and residual shear strains.
• Applicability for Cylindrical Specimens: Designed for wires, tubes, and bars, providing a semi-finished material assessment representative of many engineering applications.
• Reproducibility and Control: Details on control modes (axially free or constrained), ensuring uniform temperature and valid result consistency.
• Evaluation of Two Way Shape Memory Effect (TWSME): Enables assessment of reversible shape changes in SMA specimens by analyzing changes in shear strain under controlled torque.
• Quality Control and Material Selection: Useful for comparison of material batches, acceptance specifications, and ongoing R&D efforts.

Applications

ASTM E3414-23 finds value across multiple sectors where SMAs are used:

• Actuator Design and Testing: By simulating real operating conditions (such as those in aerospace, robotics, or automotive components), this standard provides actionable data for design allowables and actuator performance.
• Material Characterization and Selection: Assists engineers and suppliers in selecting and specifying the best shape memory alloy materials for their applications.
• Quality Control: Offers a standardized, repeatable test for verifying batch consistency and confirming that products meet necessary transformation property specifications.
• Research and Development: Supports investigation of new SMA formulations or processing methods, enabling reliable measurement of how changes affect transformation temperatures and strains.
• Supplier-Customer Agreements: Can be used as a basis for specifying mutually agreed upon testing cycles and criteria for acceptance.

Related Standards

Implementations of ASTM E3414-23 often reference or complement these standards:

• ASTM E2207: Strain-Controlled Axial-Torsional Fatigue Testing with Thin-Walled Tubular Specimens
• ASTM F2004: Test Method for Transformation Temperature of Nickel-Titanium Alloys by Thermal Analysis
• ASTM E3097: Uniaxial Constant Force Thermal Cycling of Shape Memory Alloys
• ASTM E83: Verification and Classification of Extensometer Systems
• ASTM E209: Compression Testing at Elevated Temperatures
• ASTM F2005: Terminology for Nickel-Titanium Shape Memory Alloys
• ISO 9001: Quality Management Systems

Practical Value

Adopting ASTM E3414-23 enhances reliability and comparability in SMA research, manufacturing, and quality control. Its rigorous approach to testing under constant torque makes it an indispensable tool for industries seeking to maximize the performance and reliability of shape memory alloy materials and actuators. By aligning with internationally recognized measurement protocols, this standard helps drive continuous innovation and quality in the rapidly evolving SMA field.

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.
Designation: E3414 − 23
Standard Test Method for
Constant Torque Thermal Cycling of Cylindrical Shape
Memory Alloy Specimens
This standard is issued under the fixed designation E3414; 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 E83 Practice for Verification and Classification of Exten-
someter Systems
1.1 This test method will define procedures for thermome-
E209 Practice for Compression Tests of Metallic Materials at
chanical cycling of shape memory alloys (SMA) material and
Elevated Temperatures with Conventional or Rapid Heat-
components with circular cross-sections under constant torque.
ing Rates and Strain Rates
This test method will measure the transformation properties
E606/E606M Test Method for Strain-Controlled Fatigue
such as transformation temperatures, actuation shear strain and
Testing
residual shear strain, when a shape memory alloy is thermally
E691 Practice for Conducting an Interlaboratory Study to
cycled through the phase transformation under a constant
Determine the Precision of a Test Method
applied torque. This test is done to provide data for the
E1169 Practice for Conducting Ruggedness Tests
characterization selection of shape memory alloy materials,
E2207 Practice for Strain-Controlled Axial-Torsional Fa-
quality control, design allowables and actuator design.
tigue Testing with Thin-Walled Tubular Specimens
1.2 The values stated in SI units are to be regarded as
E2368 Practice for Strain Controlled Thermomechanical
standard. No other units of measurement are included in this
Fatigue Testing
standard.
E3097 Test Method for Uniaxial Constant Force Thermal
1.3 This standard does not purport to address all of the Cycling of Shape Memory Alloys
safety concerns, if any, associated with its use. It is the
E3098 Test Method for Mechanical Uniaxial Pre-strain and
responsibility of the user of this standard to establish appro- Thermal Free Recovery of Shape Memory Alloys
priate safety, health, and environmental practices and deter-
F2004 Test Method for Transformation Temperature of
mine the applicability of regulatory limitations prior to use. Nickel-Titanium Alloys by Thermal Analysis
1.4 This international standard was developed in accor-
F2005 Terminology for Nickel-Titanium Shape Memory
dance with internationally recognized principles on standard-
Alloys
ization established in the Decision on Principles for the
2.2 Other Standards:
Development of International Standards, Guides and Recom-
IEEE/ASTM SI 10 American National Standard for Metric
mendations issued by the World Trade Organization Technical
Practice
Barriers to Trade (TBT) Committee. 3
ASQ C1 General Requirements for a Quality Program
ISO 9001 Quality Management Systems—Requirements
2. Referenced Documents
3. Terminology
2.1 ASTM Standards:
E4 Practices for Force Calibration and Verification of Test-
3.1 Definitions—The terms specific to this test method are
ing Machines
defined in this section. All other terms used in this test method
E21 Test Methods for Elevated Temperature Tension Tests of
are in accordance with Terminologies in Terminology F2005,
Metallic Materials
Practice E2207, Test Method E3097 and Test Method E3098.
All shear stress and shear strain defined in this test method are
determined on the outer diameter in accordance with Practice
E2207, unless otherwise stated.
This test method is under the jurisdiction of ASTM 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 Nov. 1, 2023. Published November 2023. DOI:
10.1520/E3414–23 Available from American Society for Quality (ASQ), 600 N. Plankinton Ave.,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Milwaukee, WI 53203, http://www.asq.org.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available from International Organization for Standardization (ISO), ISO
Standards volume information, refer to the standard’s Document Summary page on Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
the ASTM website. Switzerland, https://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3414 − 23
3.1.1 Discussion—During thermomechanical cycling of 3.2.4 cooling transformation shear strain (γ ), n—the shear
ct
shape memory alloys (SMA) material shear stain typically strain recovery due to the martensitic transformation obtained
varies non-linearly through the wall of the specimen, with the
when cooling at a specified shear stress.
smallest and largest values occurring at the inner and outer
γ 5 γ 2 γ
ct Ms Mf
diameters of the specimen, respectively. Furthermore, this test
3.2.5 heating transformation shear strain (γ ), n—the shear
method allows for testing of specimens that do not meet the ht
strain recovery due to the austenitic transformation obtained
thin-walled condition as described in Practice E2207.
when heating at a specified shear stress.
Therefore, shear strain and shear stress results determined on
the outer diameter should be considered representative of
γ 5 γ 2 γ
ht As Af
specimens of the NiTi based material and outer to inner
3.2.6 initial loading shear strain (γ ), n—initial specimen
i
diameter ratio being tested.
strain after normalization and before cooling when loaded at
3.2 Definitions of Terms Specific to This Standard:
the UCT. (See Fig. 1.)
3.2.1 actuation shear strain (γ ), n—the shear strain recov-
act
3.2.7 initial shear strain (γ ), n—specimen shear strain at
ery obtained when heating from LCT to UCT at a specified
UCT after normalizing (see 10.1) and prior to loading the
shear stress.
specimen. (See Fig. 1.)
γ 5 γ 2 γ
act LCT UCT
3.2.8 martensite finish shear strain (γ ), n—shear strain
Mf
3.2.2 austenite finish shear strain (γ ), n—shear strain
Af
determined at the martensite finish temperature during cooling
determined at the austenite finish temperature during final
as described in 10.3. (See Fig. 1.)
heating as described in 10.3. (See Fig. 1.)
3.2.9 martensite start shear strain (γ ), n—shear strain
3.2.3 austenite start shear strain (γ ), n—shear strain
Ms
As
determined at the austenite start temperature during final determined at the martensite start temperature during cooling
heating as described in 10.3. (See Fig. 1.) as described in 10.3. (See Fig. 1.)
NOTE 1—In cases where the starting point labeled “Start” coincides with the UCT, such as for the case of low temperature SMAs that are austenitic
at room temperature, the same procedure applies with the exception that the normalization step labeled (0.1) is no longer needed.
FIG. 1 Typical Constant Torque Thermal Cycle and Test Methods Terms
E3414 − 23
3.2.10 residual shear strain (γ ), n—the final shear strain at 4.7 This test method is useful for quality control, specifica-
res
the upper cycle temperature (UCT) minus the initial shear tion acceptance, and research.
strain at the UCT.
4.8 Transformation temperatures derived from this test
γ 5 γ 2 γ
method may not agree with those obtained by other test
res UCT i
methods due to the effects of shear strain and shear stress on
3.2.11 shear strain at the lower cycle temperature (γ ),
LCT
the transformation.
n—specimen shear strain at the LCT after cooling from the
UCT to the LCT under the specified shear stress. (See Fig. 1.)
4.9 Components such as springs, specimens with non-
circular cross-sections or other semi-finished parts can be
3.2.12 shear strain at the upper cycle temperature (γ ),
UCT
tested using this method as agreed upon by the customer and
n—specimen shear strain at the UCT after cooling to the LCT
supplier. Test parameters and results shall be determined with
and heating to the UCT at the specified shear stress. (See Fig.
respect to torque and rotation measured at the ends of the active
1.)
region of the specimen.
3.3 Acronyms:
3.3.1 CTTC, n—constant torque thermal cycling of cylindri-
5. Interferences
cal shape memory alloy specimens
5.1 The initial condition of the test specimen can signifi-
3.3.2 LCT, n—lower cycle temperature
cantly impact test results.
3.3.3 TWSME, n—two way shape memory effect
NOTE 1—Care should be taken to assure the material is free of
unintended residual stresses from fabrication, processing, or handling.
3.3.4 UCT, n—upper cycle temperature
Cutting and grinding can cause cold work which affects the transformation
3.4 See also Terminology E4.
temperatures. Oxidation during heat treatment can change the thermal
properties of the specimen and affect the temperature uniformity. Such
effects are magnified by specimens with smaller gauge diameters.
4. Significance and Use
5.2 When testing cylindrical bar, rod, tube and wire with
4.1 Constant torque thermal cycling tests determine the
clamped end connections, make sure that the gripping mecha-
effect of shear stress on the transformation properties such as
nism does not cause errors in strain measurement, for example
transformation temperatures, actuation shear strain and re-
slipping in the grips.
sidual shear strain of a shape memory alloy. This test is done
to provide data for the characterization selection of shape
5.3 The extensometer design and size shall be chosen so that
memory alloy materials, quality control, design allowables and
the extensometer measures relevant deformation, respectively,
actuator design (1-3). The tests should be used for one thermal
within a representative section of the gauge length of the
cycle but may be used for repeated thermal cycles as agreed
sample.
upon between supplier and customer.
5.4 Complete thermal transformation is required for accu-
4.2 Measurement of the specimen’s motion closely parallels
rate results. The material’s martensite finish and austenite
many shape memory actuator applications and provides a result
finish temperatures may be estimated prior to the test by
that is applicable to the function of the material.
Differential Scanning Calorimetry (Test Method F2004), Uni-
axial Constant Force Thermal Cycling (Test Method E3097) or
4.3 This test method may be used for cylindrical specimens
Uniaxial Pre-strain and Thermal Free Recovery (Test Method
such as wire, round tube or bar forms. Thus, it is able to
E3098).
provide an assessment of the product in its semi-finished form.
5.5 Make sure that the heating and cooling system maintains
4.4 This test method provides a simple method for deter-
a uniform specimen temperature within 6 3 °C, along the
mining transformation temperatures by heating and cooling
specimen length, over the gauge section. Temperature gradi-
specimens through their full thermal transformation under
ents in the specimen will affect the apparent transformation
torque.
temperatures and strains. See 9.1 for details on temperature
4.5 This test method may also be used to evaluate partial
measurement.
transformation cycles as set by the LCT and UCT and agreed
5.6 The heating and cooling rate for the test shall be
upon between the user and customer. Examples of partial and
consistent with the sample thickness so that the test section of
full transformation thermal cycles are provided in Fig. 2.
the specimen is at a uniform temperature within 6 3 °C,
4.6 This test method can be used on trained and processed
transverse to the specimen length, over the gauge section. See
material in a semi-finished form to measure Two Way Shape
9.1 for details on temperature measurement.
Memory Effect (TWSME) by comparing the shear strain at the
NOTE 2—Requirements specified in interferences 5.5 and 5.6 may be
LCT and UCT with a torque set such that the corresponding
achieved by selecting hold times at the UCT and LCT to ensure the
shear stress shall not exceed 7 MPa. For determining TWSME
specimen and temperature control system are fully equilibrated before
starting/continuing the thermal cycle.
in this manner it is suggested that a full transformation cycle be
performed in accordance with 5.7.
5.7 For full transformation cycle make sure the specimen is
fully austenitic at the UCT for all stress levels to be tested. This
is shown graphically in Fig. 2. It is selected to be higher than
the A determined by a DSC test in accordance with Test
The boldface numbers in parentheses refer to the list of references at the end of f
this standard. Method F2004. For example, a temperature between 10 °C to
E3414 − 23
NOTE 1—A) UCT sufficient for complete Austenitic transformation. B) UCT not sufficient for complete Austenitic transformation. “τ” is the applied
shear stress.
FIG. 2 Effects of Shear Stress and Upper Cycle Temperature on Test Results
E3414 − 23
100 °C above A may be selected in consideration of the stress 6.4 Extensometers—The torsion-axial extensometery is as
f
applied to the specimen. The DSC test shall be done on the described in Practice E2207 with the following additions.
sample material from the same lot and with the same thermo- Non-contact extensometer methods maybe used as agreed upon
mechanical history as the test material. between the customer and the supplier. Ref. (1) shows an
example of non-contact extensometry used during thermome-
5.8 For full transformation cycle make sure that the speci-
chanical cycling of shape memory alloy torsional specimens to
men is fully martensitic at the LCT. It is selected to be 10 °C
acquire shear strain data. For wires and specimens in compo-
to 30°C lower than M determined by a DSC test in accordance
f
nent form, angular displacement may be measured between the
with Test Method F2004. However, the DSC test shall be done
grips and shear strain shall be determined in accordance with
on the sample material from the same lot and with the same
Practice E2207, as was done in Ref. (3, 7, 8).
thermomechanical history as the test material.
NOTE 3—Transformation temperatures will vary with applied stress to
7. Sampling, Test Specimens, and Test Units
the specimen and also vary from alloy to alloy subjected to the same
7.1 The number and location of samples from each lot of
stress. For unfamiliar alloys it is recommended that a range of stresses be
te
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