1、Designation: D1708 10D1708 13Standard Test Method forTensile Properties of Plastics by Use of MicrotensileSpecimens1This standard is issued under the fixed designation D1708; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers certain
3、material specifications for which a history of data has been obtained using the standardmicrotensile specimen. The specimen geometry has been changed to be equivalent to that of ISO 12086-2:1995. In general, thistest method is superseded for general use by either Test Methods D882 or Test Method D63
4、8. The very small Type V specimenin Test Method D638 is the recommended specimen when limited amounts of material are available.1.2 This test method covers the determination of the comparative tensile strength and elongation properties of plastics in theform of standard microtensile test specimens w
5、hen tested under defined conditions of pretreatment, temperature, humidity, andtesting machine speed. It can be used for This method is applicable when using specimens of any thickness up to 3.2 mm (18 in.),including thin films.1.3 This test method cannot be used for the determination of modulus of
6、elasticity. For the determination of modulus, see TestMethod D638 or Test Methods D882.1.4 Test data obtained by this test method are relevant and appropriate for use in engineering design.1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are for infor
7、mation only.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.NOTE
8、1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD638 Test Method for Tensile Properties of PlasticsD882 Test Method for Tensile Properties of Thin Plastic SheetingD883 Terminology Relating to PlasticsD40
9、00 Classification System for Specifying Plastic MaterialsD5947 Test Methods for Physical Dimensions of Solid Plastics SpecimensD6988 Guide for Determination of Thickness of Plastic Film Test SpecimensE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2
10、 ISO Standard:ISO 12086-2:1995 PlasticsFluoropolymer Dispersion, Moulding, and Extrusion MaterialsPart 2 Preparation of TestSpecimens and Determination of Properties33. Terminology3.1 Definitions: DefinitionsDefinitions of terms applying to this test method appear in Terminology D883 and Test Method
11、D638, Annex A2.1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved April 1, 2010Sept. 1, 2013. Published April 2010September 2013. Originally approved in 1959. Last pr
12、evious edition approved in 20062010 asD1708 - 06a.D1708 - 10. DOI: 10.1520/D1708-10.10.1520/D1708-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Do
13、cument Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM
14、 recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO B
15、ox C700, West Conshohocken, PA 19428-2959. United States14. Significance and Use4.1 This test method provides data for quality control and acceptance or rejection under specifications.4.2 Before proceeding with this test method, reference should be made to the ASTM specification of the material bein
16、g tested.Any test specimen preparation, conditioning, dimensions, or testing parameters, or combination thereof, covered in the materialsspecification shall take precedence over those mentioned in this test method. If there are no material specifications, then the defaultconditions herein apply. Tab
17、le 1 of Classification System D4000 lists the ASTM materials standards that currently exist.5. Apparatus5.1 The apparatus shall be as specified in Test Method D638, with the following exceptions:5.1.1 GripsSerrated Use serrated grips faces should be used with care, since yielding or tearing at the g
18、rips may interfere withmeasurement of elongation even when the specimen breaks in the reduced section. Grips with rubber coated faces arerecommended for thin specimens. Care should be taken when selecting and using self tightening grips.Those which Self-tighteninggrips that move as they tighten and
19、result in a change in the grip separation between upper and lower grips are not satisfactoryfor this test method. If the specimen tab is not long enough to prevent the grip faces from cocking, shims should be inserted useshims to provide more uniform clamping.5.1.2 Drive MechanismThe velocity of the
20、 drive mechanism shall be regulated as specified in Section 8.5.1.3 The fixed and movable members, drive mechanism, and grips shouldshall be constructed of such materials and in suchproportions that, after grip slack is taken up, the total elastic longitudinal deformation of the system constituted b
21、y these parts doesnot exceed 1 % of the total longitudinal deformation between the grips at any time during the test. If this is not possible, appropriatecorrections shall be made in the calculation of strain values.5.1.4 Extension IndicatorThe extension indicator shall be capable of determining the
22、 distance between grips at any timeduring the test. The instrument shall be essentially free of inertia lag at the specified speed of testing, and shall be accurate to61 %of extension or better.NOTE 2It is desirable that the load indicator and the extension indicator be combined into one instrument,
23、 which automatically records the load asa function of the extension or as a function of time. In the latter case, the conversion to a load-extension record can readily be made because extensionis proportional to time after the take-up of the initial grip slack.5.1.5 MicrometersMicrometers shallAppar
24、atus for measuring the width and thickness of the test specimen shall comply withthe requirements of Test Method D5947 and shall read to 0.0025 mm (0.0001 in.) or less. Measure film thickness in accordancewith Guide D6988.6. Test Specimens6.1 Microtensile test specimens shall conform to the dimensio
25、ns shown in Fig. 1. This specimen shall be prepared by injectionmolding, die-cutting or machining from sheet, plate, slab, or finished article. Dimensions of a die suitable for preparing die-cutspecimens are also shown in Fig. 1. Specimens may also be prepared by injection molding or compression mol
26、ding.6.2 All surfaces of the specimen shall be free of visible flaws, scratches, or imperfections. Marks left by coarse machiningoperations shall be carefully removed with a fine file or abrasive, and the filed surfaces shall then be smoothed with abrasive paper(No. 00 or finer). The finishing sandi
27、ng strokes shall be made in the direction parallel to the long axis of the test specimen.NOTE 3Tabs shown in Fig. 1 are minimum size for adequate gripping. Shims may be required with thicker specimens to keep grips from cocking.Handling is facilitated and gripping improved by the use of larger tabs
28、wherever possible.7. Number of Test Specimens7.1 At least five test specimens shall be tested for each sample in the case of isotropic materials.TABLE 1 Tensile Strength at Break for Seven Laboratories andTwo Materials, MPaMaterialTestSpeed,mm/minAverage SrA SRB rC RDPolyamide(imide) 1.3 193.6 1.60
29、5.48 4.48 15.3Polybutylene 12.7 31.3 0.80 2.75 9.12 9.12ASr is the within-laboratory standard deviation for the indicated material. It isobtained by pooling the within-laboratory standard deviations of the test resultsfrom all of the participating laboratories:Sr5ffsS1d21sS2d211sSnd2g/ng1/2. (1)BSR
30、is the between-laboratories reproducibility, expressed as a standard deviation,for the indicated material.Cr is the within-laboratory repeatability limit, r = 2.8 Sr.DR is the between-laboratory reproducibility limit, R = 2.8 SR.D1708 1327.2 Ten test specimens, five normal to and five parallel to th
31、e principal axis of anisotropy, shall be tested for each sample inthe case of anisotropic materials.7.3 Results obtained on test specimens that break at some obvious fortuitous flaw or at the edge of the grips shall be discardedand retests made, unless such flaws constitute a variable, the effect of
32、 which it is desired to study.8. Speed of Testing8.1 Speed of testing is the velocity of separation of the two members (or grips) of the testing machine when running idle (underno load).NOTE 1All dimensions are in millimetres.FIG. 1 Microtensile Die and Test SpecimenD1708 1338.2 The speed of testing
33、 shall be chosen such that the rate of straining shall be approximately the same as the rate of strainingobtained when the material is tested at the designated speed according to Test Method D638. Speeds giving rates of strainingapproximating those given in Test Method D638 are as follows:Speed A 0.
34、25 mm (0.01 in.)/minSpeed B 1 to 1.3 mm (0.04 to 0.05 in.)/minSpeed C 10 to 13 mm (0.4 to 0.5 in.)/minSpeed D 100 to 130 mm (4 to 5 in.)/minThese speeds are 0.20 to 0.25 times the speeds designated inTest Method D638, since the effective gauge length of bars specifiedin the latter test method is fou
35、r to five times that of the microtensile test specimens. When the speed of testing is not specified,Speed B shall be used.9. Conditioning9.1 ConditioningCondition the test specimens in accordance with Procedure A of Practice D618, unless otherwise specifiedby contract or the relevantASTM material sp
36、ecification. Temperature and humidity tolerances shall be in accordance with Section7 of Practice D618 unless specified differently by contract or material specification.9.2 Test ConditionsConduct the tests at the same temperature and humidity used for conditioning with tolerances inaccordance with
37、Section 7 of Practice D618 unless otherwise specified by contract or the relevant ASTM material specification.10. Procedure10.1 Test specimens shall be tested at the standard laboratory atmosphere as defined in Practice D618, unless otherwisespecified.10.2 Measure and record the minimum value of the
38、 cross-sectional area of each specimen. Measure the width to the nearest0.025 mm (0.001 in.) and the thickness to the nearest 0.0025 mm (0.0001 in.) for specimens less than 2.5 mm (0.1 in.) thick, orto the nearest 0.025 mm (0.001 in.) for specimens 2.5 mm (0.1 in.) or greater in thickness.10.3 Set t
39、he testing machine so that the distance between the upper and lower (or opposing) grips is 22.00 6 0.05 mm (0.8666 0.002 in.), unless otherwise directed by the pertinent ASTM material specification. This distance shall be measured with thegrips in the closed position.NOTE 4This mayis easily be check
40、ed by the use of a 22.00-mm (0.886-in.)(0.866-in.) gauge block or a pair of inside calipers.10.4 Place the specimen in the grips of the testing machine with the inside edge of each tab visible at the edge of the grip. Toensure uniform axial tensile stress within the gauge length, the axis of the tes
41、t specimen shouldshall coincide with the center lineof the grips of the test machine. Tighten the grips evenly and firmly to the degree necessary to prevent slippage of the specimenduring the test, but not to the point where the specimen would be crushed.10.5 Set the speed control at the speed desir
42、ed (8.2) and start the machine.10.6 Record the load at the yield point (if one exists), the maximum load carried by the specimen during the test, the load atrupture, and the elongation (extension between grips) at the moment of rupture.11. Calculation11.1 Yield Strength, Tensile Strength, and Tensil
43、e Strength at BreakCalculate the yield strength, tensile strength, and tensilestrength at break in accordance with Test Method D638.11.2 Percentage Elongation at BreakCalculate the percentage elongation at break by dividing the elongation (extension) atthe moment of rupture of the specimen by the or
44、iginal distance between the grips, and multiplying by one hundred. Report thepercentage elongation to two significant figures.11.3 Percentage Elongation at the Yield PointCalculate the percentage elongation at the yield point, if desired, by dividingthe elongation (extension) at the yield point by t
45、he original distance between the grips, and multiplying by one hundred. Reportthe percentage elongation to two significant figures.11.4 Calculate the “average value” and standard deviation for each property in accordance with Test Method D638.12. Report12.1 Results of this test method shall not be r
46、eported as having been obtained in accordance with Test Methods D882 or TestMethod D638 regardless of any modifications that might be made to simulate those testing parameters.12.2 Report the following information:12.2.1 Complete identification of the material tested, including type, source, manufac
47、turers code numbers, form, principaldimensions, previous history, and other pertinent information,12.2.2 Method of preparing test specimens,12.2.3 Specimen thickness,D1708 13412.2.4 Conditioning procedure used,12.2.5 Atmospheric conditions in test room,12.2.6 Number of specimens tested,12.2.7 Speed
48、of testing,12.2.8 Yield strength (if any), average value, and standard deviation,12.2.9 Tensile strength, average value, and standard deviation,12.2.10 Tensile strength at break, average value, and standard deviation,12.2.11 Percentage elongation at break, average value, and standard deviation,12.2.
49、12 Percentage elongation at the yield point, average value, and standard deviation (if desired),12.2.13 Date of test, and12.2.14 Date of test method.13. Precision and Bias13.1 PrecisionTable 1 and Table 2 are based on a round robin conducted in 1995 in accordance with Practice E691, involvingtwo materials tested by seven laboratories. Polybutylene specimens were die cut from tubing. Polyamide(imide) specimens wereinjection molded. For each material, all of the specimens were prepared at one source. Each test result is the average of fiveindividual determ
