Work Item
ASTM WK82345

Revision of E3097-17 Standard Test Method for Mechanical Uniaxial Constant Force Thermal Cycling of Shape Memory Alloys


In 2017 the “Standard Test Method for Mechanical Uniaxial Constant Force Thermal Cycling (UCFTC)” was published for the first time as E3097. Since its publication several revisions have been suggested and tracked. This work item intends to ballot the suggested revisions. Furthermore, the test method is due for balloting. These suggested revisions are summarized as follows:

- Revision: Mechanical removed from title.
Rationale: Redundant and implied by Uniaxial Constant Force
- Revision: Editorial changes to scope.
"1.1 This test method defines procedures for thermomechanical cycling of shape memory alloys (SMA) material and components under constant force. This method characterizes the transformation properties such as transformation temperatures, actuation strain and residual strain, when a SMA is thermally cycled through the phase transformation under a constant applied force. This test is done to provide data for the selection of SMA materials, quality control, design allowables and actuator design."
Rationale: To clarify without changing intent
- Revision: Transformation strain (3.1.5) is changed to heating transformation strain
Rationale: To distinguish between cooling and heating transformation strains
- Revision: Cooling transformation strain (3.1.6) was added
Rationale: To distinguish between cooling and heating transformation strains
- Revision: User or program now specifies Lower Cycle Temperature (LCT) and Upper Cycle Temperature (UCT)
"The LCT and UCT shall be defined by the program and shall be in accordance within the limits in the terminology of Paragraphs 6.7 and 6.8. If a LCT or UCT is not defined it shall be determined by test in accordance with Paragraphs 6.7 and 6.8."
Rationale: After several years of use, this is how the test method is typically being used. An ILS is currently being conducted and specifies LCT and UCT.
- Revision: 5.1 Constant force thermal cycling tests determine the effect of stress on the transformation temperatures, recovered strain and residual strain of a shape memory alloy. The tests may be for one thermal cycle but may involve repeated thermal cycles. Remove: "with the number of cycles increasing by orders of magnitude 10 until the response of the material to thermal cycling no longer changes."
Rationale: The statement has little meaning in this context. A new test method is being written to describe repeated thermal cycling.
- Revision: Figure 2 clarifies strains determined at transformation temperatures, example (Af, eAf)
Rationale: These points are not actual data points and are extracted by analysis, which is the tangent fit method. This is to clarify their location and meaning.
- Revision: Added.
5.2 Measurement of the specimen's thermomechanical behavior closely parallels many shape memory applications and provides a result that is applicable to the function of the material.
5.3 This test method may be used for, but is not limited to, wire, round tube, or strip samples. Thus it is able to provide an assessment of the product in its semi-finished form.
5.4 This test method provides a simple method for determining transformation temperatures by heating and cooling specimens through their full thermal transformation under force.
5.5 This test method can be used on trained and processed material in a semi-finished form to measure Two Way Shape Memory Effect by comparing the strain in the austenite state and martensite states with no applied stress.
5.6 This test method is useful for quality control, specification acceptance, and research.
5.7 Transformation temperatures derived from this test method may not agree with those obtained by other test methods due to the effects of strain and stress on the transformation.
5.8 Components such as springs or other semi-finished parts can be tested using this method as agreed upon by the customer and supplier. Units of stress and strain can be replaced with force and displacement.
Rationale: To be consistent with E3098. All of these uses are relevant to E3097 as well.


Developed by Subcommittee: E08.05

Committee: E08

Staff Manager: Brian Milewski

Work Item Status

Date Initiated: 06-20-2022

Technical Contact: Douglas Nicholson

Item: 016

Ballot: E08 (22-03)

Status: Negative Votes Need Resolution