1、Designation: F 2005 05Standard Terminology forNickel-Titanium Shape Memory Alloys1This standard is issued under the fixed designation F 2005; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in pa
2、rentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This terminology is a compilation of definitions of termsused in ASTM documents relating to nickel-titanium shapememory alloys used for medical de
3、vices. This terminologyincludes only those terms for whichASTM either has standardsor which are used inASTM standards for nickel-titanium shapememory alloys. It is not intended to be an all-inclusive list ofterms related to shape memory alloys.1.2 Definitions that are similar to those published by a
4、notherstandards body are identified with abbreviations of the name ofthat organization; for example, ICTAC is the InternationalConfederation for Thermal Analysis and Calorimetry.1.3 A definition is a single sentence with additional infor-mation included in a discussion. This standard is reviewedever
5、y five years, and the year of the last revision is appended.2. Referenced Documents2.1 ASTM Standards:2E7 Terminology Relating to MetallographyE 473 Terminology Relating to Thermal AnalysisF 2004 Test Method for Transformation Temperature ofNickel-Titanium Alloys by Thermal AnalysisF 2082 Test Metho
6、d for Determination of TransformationTemperature of Nickel-Titanium Shape Memory Alloys byBend and Free Recovery3. Terminologyactive austenite finish temperature, nterm used to denoteaustenite finish temperature of a finished wire, tube, orcomponent as determined by a bend and free recoverymethod ra
7、ther than by DSC.alloy phase, nin a shape memory alloy, the crystal structurestable at a particular temperature and stress.anneal, vto heat treat in order to remove the effect ofcold-working.austenite, nthe high temperature parent phase in Ni-Ti shapememory alloys with a B2 crystal structure. This p
8、hasetransforms to R-phase or martensite, or both, on cooling.austenite finish temperature (Af), nthe temperature atwhich the martensite to austenite transformation is com-pleted on heating in a single-stage transformation (Fig. 1)orthe temperature at which the R-phase to austenite transfor-mation is
9、 completed on heating in a two-stage transforma-tion (Fig. 2).austenite peak temperature (Ap), nthe temperature of theendothermic peak position on the differential scanningcalorimeter (DSC) curve upon heating for the martensite toaustenite transformation in a single-stage transformation(Fig. 1) or t
10、he temperature of the endothermic peak positionon the DSC curve upon heating for the R-phase to austenitetransformation in a two-stage transformation (Fig. 2).austenite start temperature (As), nthe temperature atwhich the martensite to austenite transformation begins onheating in a single-stage tran
11、sformation (Fig. 1)orthetemperature at which the R-phase to austenite transformationbegins on heating in a two-stage transformation (Fig. 2).bend and free recovery (BFR), na test method for deter-mining austenite transformation temperatures on heating.DISCUSSIONThe test involves cooling a wire or tu
12、be specimenbelow the Mftemperature, deforming the specimen in a controlledfashion, then heating through the austenite transformation. By measur-ing the shape memory response of the specimen Asand Af, tempera-tures can be determined. This test method is covered in Test MethodF 2082.differential scann
13、ing calorimeter (DSC), na device that iscapable of heating a test specimen and a reference at acontrolled rate and of automatically measuring the differencein heat flow between the specimen and the reference both tothe required sensitivity and precision.differential scanning calorimetry (DSC), na te
14、chnique inwhich the difference in heat flow into or out of a substanceand an inert reference is measured as a function of tempera-ture while the substance and the reference material aresubjected to a controlled temperature program. This testmethod, as it applies to Ni-Ti shape memory alloys, iscover
15、ed in Test Method F 2004. (E 473) (ICTAC) (1993)1This terminology is under the jurisdiction ofASTM Committee F04 on Medicaland Surgical Devices and is the direct responsibility of Subcommittee F04.12 onMetallurgical Materials.Current edition approved Oct. 1, 2005. Published October 2005. Originallya
16、pproved in 2000. Last previous edition approved in 2000 as F 2005 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM
17、website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.free recovery, nunconstrained motion of a shape memoryalloy upon heating and transformation to austenite afterdeformation below the austenite phase.linear elasticity, nlinear re
18、coverable deformation behavior.DISCUSSIONNo significant phase transformation event occurs whilestraining the material and the tensile load-extension or stress-strain plotis linear upon loading and unloading.lower plateau strength (LPS), nthe stress at 2.5 % strainduring tensile unloading of the samp
19、le, after loading to 6 %strain.martensite, nthe lowest temperature phase in Ni-Ti shapememory alloys with a B198 (B19 prime) monoclinic crystalstructure.martensite deformation temperature (Md), nthe highesttemperature at which martensite will form from the austenitephase in response to an applied st
20、ress.martensite finish temperature (Mf), nthe temperature atwhich the transformation from austenite to martensite iscompleted on cooling in a single-stage transformation (Fig.1) or the temperature at which the transformation fromR-phase to martensite is completed on cooling in a two-stagetransformat
21、ion (Fig. 2).martensite peak temperature (Mp), nthe temperature ofthe exothermic peak position on the DSC curve upon coolingfor the austenite to martensite transformation (Fig. 1)ortheR-phase to martensite transformation (Fig. 2).martensite start temperature (Ms), nthe temperature atwhich the transf
22、ormation from austenite to martensite beginson cooling in a single-stage transformation (Fig. 1)orthetemperature at which the transformation from R-phase tomartensite begins on cooling in a two-stage transformation(Fig. 2).nitinol, na generic name for a Ni-Ti alloy.pseudoelasticity, nSee superelasti
23、city.R-phase, nthe intermediate phase which may form betweenaustenite and martensite.DISCUSSIONThis occurs in Ni-Ti shape memory alloys under certainconditions. The crystal lattice of the R-Phase is a rhombohedraldistortion of the cubic austenite crystal lattice structure, hence the name“R-phase.”R-
24、phase finish temperature (Rf), nthe temperature atwhich the transformation from austenite to R-phase iscompleted on cooling in a two-stage transformation (Fig. 2).R-phase peak temperature (Rp), nthe temperature of theexothermic peak position on the DSC curve upon cooling forthe austenite to R-phase
25、transformation (Fig. 2).R-phase start temperature (Rs), nthe temperature at whichthe transformation from austenite to R-phase begins oncooling in a two-stage transformation (Fig. 2).R*-phase finish temperature (R*f), nthe temperature atwhich the martensite to R-phase transformation is completedon he
26、ating in a two-stage transformation (Fig. 2).R*-phase peak temperature (R*p), nthe temperature of theendothermic peak position on the DSC curve upon heating,for the martensite to R-phase transformation in a two-stagetransformation (Fig. 2).R*-phase start temperature (R*s), ntemperature at whichthe m
27、artensite to R-phase transformation begins on heatingin a two-stage transformation (Fig. 2).residual elongation (Elr%), nthe strain after tensile load-ing to 6 % strain and unloading to 7 MPa.shape memory alloy, na metal which, after an apparentplastic deformation in the martensitic phase, undergoes
28、 athermoelastic change in crystal structure when heatedthrough its transformation temperature range resulting in arecovery of the deformation.solution anneal, solution heat treatment, vto heat treat inorder to remove precipitates.superelasticity, nnonlinear recoverable deformation behav-ior of Ni-Ti
29、 shape memory alloys at temperatures above theaustenite finish temperature (Af).DISCUSSIONThe nonlinear deformation arises from the stress-induced formation of martensite on loading and the spontaneousreversion of this crystal structure to austenite upon unloading.FIG. 1 DSC Graph for a Single-Stage
30、 TransformationFIG. 2 DSC Graph for a Two-Stage TransformationF2005052thermoelastic martensitic transformation, na diffusion-less thermally reversible phase change characterized by achange in crystal structure.DISCUSSIONThis is a process in which an incremental change intemperature produces a propor
31、tionate increase or decrease in theamount of phase change.transformation temperature range, nin a shape memoryalloy, the temperature range in which a change of phaseoccurs. (E7) (1988)upper plateau strength (UPS), nthe stress at 3% strainduring tensile loading of the sample.ASTM International takes
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