1、Designation: F 2004 05Standard Test Method forTransformation Temperature of Nickel-Titanium Alloys byThermal Analysis1This standard is issued under the fixed designation F 2004; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method defines procedures for determining thetransformation temperatures of nickel-titanium shape me
3、moryalloys.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and to d
4、etermine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 473 Terminology Relating to Thermal AnalysisE 967 Practice for Temperature Calibration of DifferentialScanning Calorimeters and Differential Thermal AnalyzersE 1142 Terminology Relating to T
5、hermophysical PropertiesF 2005 Terminology for Nickel-Titanium Shape MemoryAlloys3. Terminology3.1 Specific technical terms used in this test method arefound in Terminologies E 473, E 1142, and F 2005.4. Summary of Test Method4.1 This test method involves heating and cooling a testspecimen at a cont
6、rolled rate in a controlled environmentthrough the temperature interval of the phase transformation.The difference in heat flow between the test material and areference material due to energy changes is continuouslymonitored and recorded. Absorption of energy due to a phasetransformation in the spec
7、imen results in an endothermic peakon heating. Release of energy due to a phase transformation inthe specimen results in an exothermic peak on cooling.5. Significance and Use5.1 Differential scanning calorimetry provides a rapidmethod for determining the transformation temperature(s) ofnickel-titani
8、um shape memory alloys.5.2 This test method uses small, stress-free, annealedsamples to determine whether a sample of nickel-titanium alloycontaining nominally 54.5 to 56.5 % nickel by weight isaustenitic or martensitic at a particular temperature. Sincechemical analysis of these alloys does not hav
9、e sufficientprecision to determine the transformation temperature bymeasuring the nickel to titanium ratio of the alloy, directmeasurement of the transformation temperature of an annealedsample of known thermal history is recommended.5.3 This test method is useful for quality control, specifica-tion
10、 acceptance, and research.5.4 Transformation temperatures derived from differentialscanning calorimetry (DSC) may not agree with those obtainedby other test methods due to the effects of strain and load on thetransformation.6. Interferences6.1 Make sure the material to be tested is homogeneoussince
11、milligram sample quantities are used.6.2 Take care in preparing the sample. Cutting and grindingcan cause cold work, which affects the transformation tempera-ture. Oxidation during heat treatment can change the thermalconductance of the sample.6.3 Set the gas flow to provide adequate thermal conduct
12、iv-ity in the test cell.7. Apparatus7.1 Use a differential scanning calorimeter capable of heat-ing and cooling at rates up to 10C/min and of automaticallyrecording the differential energy input between the specimenand the reference to the required sensitivity and precision.7.2 Use sample capsules o
13、r pans composed of aluminum orother inert material of high thermal conductivity.1This test method is under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.15 on Material Test Methods.Current edition approved Oct.
14、 1, 2005. Published November 2005. Originallypublished in 2000. Last previous edition published in 2003 as F 2004 03.2For 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
15、 the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.3 Use helium gas purge supply. See 10.3.1.7.4 Use an analytical balance with a capacity of 100 mgcapable of weighing to the nea
16、rest 0.1 mg.8. Sampling8.1 Use a sample size of 25 to 45 mg. Cut the sample tomaximize surface contact with the (DSC) sample pan.8.2 Anneal the sample at 800 to 850C for 15 to 60 min invacuum or inert atmosphere, or in air with adequate protectionfrom oxidation. Rapidly cool the sample to prevent pr
17、ecipita-tion of phases which may change transformation temperatureof the alloy.8.3 Clean the sample of all foreign materials such as cuttingfluid. If the sample is oxidized in heat treatment, grind, polish,or etch the sample to remove the oxide. Take care to avoid coldworking the sample as this will
18、 change its thermal response.Slight oxidation is permissible but remove all heavy oxidescale.9. Calibration9.1 Calibrate the temperature axis of the instrument usingthe same heating rate, purge gas, and flow rate as those used foranalyzing the specimen in accordance with Practice E 967.10. Procedure
19、10.1 Place the sample on the sample pan and place the panon the test pedestal.10.2 Place an empty pan on the reference pedestal.10.3 Turn on the purge gas at a flow rate of 10 to 50mL/min.10.3.1 Use helium as the purge gas for the sample chamber.10.3.2 Use a dry air, helium, or nitrogen cover gas. T
20、he drygas shall have a dew point below the lowest temperature of thecooling cycle.10.4 Run the cooling and heating program.10.4.1 Use the heating and cooling rates of 10 6 0.5C/min.10.4.2 Heat the sample from room temperature to a tem-perature of at least Af+ 30C; hold at temperature for a timesuffi
21、cient to equilibrate the sample with the furnace.10.4.3 Cool the sample to a temperature of below Mf30C; hold for a time sufficient to equilibrate the sample withthe furnace. Then, heat the sample to a temperature of at leastAf+ 30C.10.5 Data AcquisitionRecord the resulting curve from theheating and
22、 cooling program from Af+ 30C to Mf 30C.11. Graphical Data Reduction11.1 Draw the baselines for the cooling and heating portionsof the curve as shown in Fig. 1.11.2 Draw the tangents to the cooling and heating spikesthrough the inflection points as shown in Fig. 1. If a computerprogram is used to co
23、nstruct the tangents, care must be taken inlocating the tangent points.11.3 Obtain Ms,Mf,As, and Afas the graphical intersectionof the baseline with the extension of the line of maximuminclination of the appropriate peak of the curve as shown inFig. 1.Apis the peak minimum of the endothermic curve,
24、andMpis the peak maximum of the exothermic curve. ReadApandMpdirectly from the graph as shown in Fig. 1.12. Report12.1 Report the following information with the test results:12.1.1 Complete identification and description of the mate-rial tested including the specification and lot number.12.1.2 Descr
25、iption of the instrument used for the test.12.1.3 Statement of mass, dimensions, and geometry.12.1.4 Material for the specimen pan and temperature pro-gram.12.1.5 Description of the temperature calibration procedure.12.1.6 Identification of the specimen environment by gas,flow rate, purity and compo
26、sition.12.1.7 Results of the transformation measurements usingthe nomenclature in accordance with Terminology F 2005.Temperature results should be reported to the nearest 1C.13. Precision and Bias13.1 An interlaboratory study was conducted in accordancewith Practice E 691 in seven laboratories with
27、three differentmaterials, with each laboratory obtaining five results for eachmaterial. There were two rounds of testing. In the first round,all the test samples were annealed in one laboratory; in thesecond round, the samples were annealed by the laboratory thatconducted the test. The details are g
28、iven in ASTM ResearchReport No. F041008.33Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: F041008.FIG. 1 DSC Curve for Nickel-Titanium (NiTi)TABLE 1 Precision of MfMaterial Mf,grandmeanRepeatabilityStandardDeviationReproducibili
29、tyStandardDeviationRepeatabilityLimitReproducibilityLimitA -50.0 0.57 3.97 1.6 11.1B -26.3 0.95 2.62 2.7 7.3C 48.5 1.02 1.54 3.0 4.3F200405213.2 The results of round one are summarized in Tables 1-6for each transformation temperature parameter (Mf,Mp,Ms,As,Ap,Af). The values are in degrees Celsius.
30、The termsrepeatability limit and reproducibility limit are used as speci-fied in Practice E 177.13.3 The results of round two are summarized in Tables7-12 for each transformation temperature parameter (Mf,Mp,Ms,As,Ap,Af). The values are in degrees Celsius. The termsrepeatability limit and reproducib
31、ility limit are used as speci-fied in Practice E 177.TABLE 2 Precision of MpMaterial Mp,grandmeanRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitA -43.8 0.42 2.65 1.2 7.4B -20.5 1.10 2.21 3.1 6.2C 58.1 0.88 1.05 2.5 2.9TABLE 3 Precision of MsMateri
32、al Ms,grandmeanRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitA -41.6 0.40 2.35 1.1 6.6B -16.9 0.95 1.24 2.7 3.5C 64.8 0.74 1.15 2.1 3.2TABLE 4 Precision of AsMaterial As,grandmeanRepeatabilityStandardDeviationReproducibilityStandardDeviationRepea
33、tabilityLimitReproducibilityLimitA -25.3 0.30 1.85 0.8 5.2B -4.8 0.32 1.58 0.9 4.4C 72.9 0.65 2.68 1.8 7.5TABLE 5 Precision of ApMaterial Ap,grandmeanRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitA -19.4 0.16 1.94 0.5 5.4B 5.7 0.57 1.50 1.6 4.2C
34、94.7 0.85 3.18 2.4 8.9TABLE 6 Precision of AfMaterial Af,grandmeanRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitA -23.4 0.23 2.01 0.6 5.6B 2.5 0.67 1.39 1.9 3.9C 91.6 0.80 2.25 2.2 6.3TABLE 7 Precision of Mf, When Samples are Annealed byTesting L
35、aboratoryMaterial Mf,grandmeanRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitA -49.1 2.03 8.49 5.7 23.8B -27.3 1.85 5.93 5.2 16.6C 48.5 1.23 1.84 3.4 5.1TABLE 8 Precision of Mp, When Samples are Annealed byTesting LaboratoryMaterial Mp,grandmeanRe
36、peatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitA -43.0 1.31 8.69 3.7 24.3B -21.5 1.67 7.31 4.7 20.5C 58.1 1.31 1.47 3.7 4.1TABLE 9 Precision of Ms, When Samples are Annealed byTesting LaboratoryMaterial Ms,grandmeanRepeatabilityStandardDeviationRepr
37、oducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitA -40.7 2.84 8.29 7.9 23.2B -18.9 2.38 6.60 6.7 18.5C 64.8 1.39 2.29 3.9 6.4TABLE 10 Precision of As, When Samples are Annealed byTesting LaboratoryMaterial As,grandmeanRepeatabilityStandardDeviationReproducibilityStandardDeviationRep
38、eatabilityLimitReproducibilityLimitA -23.2 0.94 5.26 2.6 14.7B -4.1 0.52 1.93 1.4 5.4C 72.9 0.70 2.80 2.0 7.8TABLE 11 Precision of Ap, When Samples are Annealed byTesting LaboratoryMaterial Ap,grandmeanRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLim
39、itA -19.1 0.56 5.30 1.6 14.8B 2.2 0.65 2.71 1.8 7.6C 89.5 1.01 3.37 2.8 9.4TABLE 12 Precision of Af, When Samples are Annealed byTesting LaboratoryMaterial Af,grandmeanRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitA -16.6 0.87 4.95 2.4 13.9B 6.6
40、0.69 4.07 1.9 11.4C 94.7 0.91 2.61 2.5 7.3F200405314. Keywords14.1 differential scanning calorimeter; DSC; nickel-titaniumalloy; NiTi; Nitinol; shape memory alloy; TiNi; transformationtemperatureAPPENDIX(Nonmandatory Information)X1. RATIONALEX1.1 This test method uses small, stress-free, annealedsam
41、ples to determine whether a sample of nickel-titanium alloycontaining nominally 54.5 to 56.5 % nickel by weight isaustenitic or martensitic at a particular temperature. Sincechemical analysis of these alloys does not have sufficientprecision to determine the transformation temperature bymeasuring th
42、e nickel to titanium ratio of the alloy, directmeasurement of the transformation temperature of an annealedsample of known thermal history is recommended.X1.2 It is well known that slow cooling after annealing ofnickel-rich alloys allows precipitates of the Ni4Ti3type toform, thereby increasing the
43、Ti content of the matrix and thetransformation temperatures. The practice is to avoid slowcooling preserve the “as annealed” transformation. It is pos-sible, however, to cool the samples too quickly, raising thetransformation temperature, possibly due to stress effectswhich retain residual martensit
44、e. One method of achieving thedesired cooling rate is to heat treat the test specimens on a foiltray and then allow the samples and the foil tray to cooltogether, out of the furnace, in room temperature air.X1.3 Transformation temperatures derived from differentialscanning calorimetry (DSC) may not
45、agree with those obtainedby other test methods due to the effects of strain and load on thetransformation.X1.4 Differences in sample preparation techniques betweenlaboratories influenced the reproducibility limit. Differences incalibration techniques may have also influenced reproducibil-ity. To min
46、imize interlaboratory variations in results, commonsample preparation and calibration practices must beestablished.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly ad
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49、If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F2004054
