ASTM F2082-15
(Test Method)Standard Test Method for Determination of Transformation Temperature of Nickel-Titanium Shape Memory Alloys by Bend and Free Recovery
Standard Test Method for Determination of Transformation Temperature of Nickel-Titanium Shape Memory Alloys by Bend and Free Recovery
SIGNIFICANCE AND USE
5.1 This test method provides a rapid, economical method for determination of transformation temperatures.
5.2 Measurement of the specimen motion closely parallels many shape memory applications and provides a result that is applicable to the function of the material.
5.3 This test method uses wire, tube, or strip samples; thus, it is able to provide an assessment of the product in its semifinished form.
5.4 This test method may be used on annealed samples to determine the transformation temperatures and assure the alloy formulation, since chemical analysis is not precise enough to determine adequately the nickel-to-titanium ratio of shape memory alloys.
5.5 Transformation temperatures derived from this test method may differ from those derived from other methods as a result of the effects of strain and load on the transformation temperature.
5.6 The test method is applicable to shape memory alloys with Af temperatures in the range of approximately – 25 to +90°C.
SCOPE
1.1 This test method describes a procedure for determining the martensite-to-austenite transformation temperatures of either fully annealed or heat-treated nickel titanium alloys by measuring the deformation recovered during the thermal transformation.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: F2082 − 15
StandardTest Method for
Determination of Transformation Temperature of Nickel-
1
Titanium Shape Memory Alloys by Bend and Free Recovery
This standard is issued under the fixed designation F2082; 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 3.2 free recovery—unconstrained motion of a shape
memory alloy upon heating and transformation to austenite
1.1 This test method describes a procedure for determining
after deformation in a lower temperature phase.
the martensite-to-austenite transformation temperatures of ei-
ther fully annealed or heat-treated nickel titanium alloys by
3.3 Abbreviations:
measuring the deformation recovered during the thermal trans-
3.3.1 LVDT—linear variable differential transducer.
formation.
3.3.2 RVDT—rotary variable differential transducer.
1.2 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. The values stated in
4. Summary of Test Method
each system may not be exact equivalents; therefore, each
4.1 This test method involves cooling a test specimen to its
system shall be used independently of the other. Combining
nominally fully martensitic phase, deforming the specimen,
values from the two systems may result in non-conformance
and heating the specimen to its fully austenitic phase. During
with this standard.
heating, the motion of the specimen is measured and plotted
1.3 This standard does not purport to address all of the
versus the specimen temperature. For a two-stage
safety concerns, if any, associated with its use. It is the
transformation, the R’ , R’, A , and A, as defined in Terminol-
s f s f
responsibility of the user of this standard to establish appro-
ogy F2005, are determined. For a single-stage transformation,
priate safety and health practices and determine the applica-
the A and A are determined.
s f
bility of regulatory limitations prior to use.
5. Significance and Use
2. Referenced Documents
2
2.1 ASTM Standards:
5.1 This test method provides a rapid, economical method
E177 Practice for Use of the Terms Precision and Bias in
for determination of transformation temperatures.
ASTM Test Methods
5.2 Measurement of the specimen motion closely parallels
E220 Test Method for Calibration of Thermocouples By
many shape memory applications and provides a result that is
Comparison Techniques
applicable to the function of the material.
E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
5.3 This test method uses wire, tube, or strip samples; thus,
F2005 Terminology for Nickel-Titanium Shape Memory
it is able to provide an assessment of the product in its
Alloys
semifinished form.
3. Terminology 5.4 This test method may be used on annealed samples to
determine the transformation temperatures and assure the alloy
3.1 Definitions—Specific technical terms used in this test
formulation, since chemical analysis is not precise enough to
method are found in Terminology F2005.
determine adequately the nickel-to-titanium ratio of shape
memory alloys.
1
This test method is under the jurisdiction ofASTM Committee F04 on Medical
5.5 Transformation temperatures derived from this test
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.15 on Material Test Methods. method may differ from those derived from other methods as a
CurrenteditionapprovedMay1,2015.PublishedJuly2015.Originallyapproved
result of the effects of strain and load on the transformation
in 2001. Last previous edition approved in 2006 as F2082 – 06, which was
temperature.
withdrawn in January 2015 and reinstated in May 2015. DOI: 10.1520/F2082-15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.6 The test method is applicable to shape memory alloys
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
with A temperatures in the range of approximately – 25 to
Standards volume information, refer to the standard’s Document Summary page on f
the ASTM website. +90°C.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F2082 − 15
6. Apparatus 8. Calibration
6.1 LVDT, with range greater than half the mandrel diameter 8.1 The thermocouple and indicator shall be kept in a
(see 9.2), with power supply, mounted in an appropriate fixture calibrated condition, traceable to the National Institute for
with counterbalanced probe (see Fig. 1); or RVDT with range Standards and Technology or appropriate N
...
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