ASTM B871-2001(2007) Standard Test Method for Tear Testing of Aluminum Alloy Products《铝合金产品撕裂测试的标准试验方法》.pdf

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1、Designation: B 871 01 (Reapproved 2007)Standard Test Method forTear Testing of Aluminum Alloy Products1This standard is issued under the fixed designation B 871; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi

2、sion. 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 covers the static tear test of aluminumalloy products using specimens that are 0.040 in. (1 mm) to0.250 in. (

3、6.35 mm) thick.1.2 This test method is applicable to aluminum alloy prod-ucts having a minimum thickness of 0.040 in. (1 mm).1.3 This test method provides a measure of both notchtoughness and resistance to crack propagation with the primaryuse as a screening or merit rank test.1.4 The reliability of

4、 the tear test has been established invarious research programs by reasonably good correlationsbetween data from the tear tests and fracture toughness tests.2,3NOTE 1Direct measurement of fracture toughness may be made inaccordance with Practices B 645, B 646 and Test Method E 399.1.5 The values sta

5、ted in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.6 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

6、safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4B 557 Test Methods for Tension Testing Wrought and CastAluminum- and Magnesium-Alloy ProductsB 645 Practice for PlaneStrain Fracture Toughness Testingof Alum

7、inum AlloysB 646 Practice for Fracture Toughness Testing of Alumi-num AlloysE4 Practices for Force Verification of Testing MachinesE83 Practice for Verification and Classification of Exten-someter SystemsE 338 Test Method of Sharp-Notch Tension Testing ofHigh-Strength Sheet MaterialsE 399 Test Metho

8、d for Linear-Elastic Plane-Strain FractureToughness KIcof Metallic Materials3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 initiation energy, IE (FL)the amount of energyrequired to initiate a crack in a tear specimen. Initiation energyis determined by integrating the area und

9、er the force-displacement curve from the beginning of the test to the pointof maximum force.3.1.2 propagation energy, PE (FL)the amount of energyrequired to propagate a crack in a tear specimen. Propagationenergy is determined by integrating the area under the force-displacement curve from the point

10、 of maximum force to thepoint of complete fracture.3.1.3 tear resistancea general term describing the resis-tance of a material to crack propagation under static loading,either in an elastic or plastic stress field.3.1.4 tear strength, TS (FL2)the maximum nominal di-rect and bending stress that the

11、tear specimen is capable ofsustaining.3.1.5 tear strength to tensile yield strength ratio (TYR)theratio of the tear strength to tensile yield strength of the materialdetermined in accordance with Test Methods B 557.3.1.6 unit propagation energy, UPE (FL1)the amount ofenergy required to propagate a c

12、rack across a tear specimendivided by the original net area of the specimen.4. Summary of Test Method4.1 The tear test involves a single edge notched specimenthat is statically loaded through pin loading holes. The forceand displacement required to fracture the specimen are re-corded for analysis.1T

13、his test method is under the jurisdiction of ASTM Committee B07 on LightMetals and Alloys and is the direct responsibility of Subcommittee B07.05 onTesting.Current edition approved April 1, 2007. Published May 2007. Originallyapproved in 1996. Last previous edition approved in 2001 as B 87101.2Kaufm

14、an, J. G., and Holt, Marshall, “Fracture Characteristics of AluminumAlloys,” Alcoa Research Laboratories Technical Paper No. 18.3Kaufman, J. G., and Knoll,A. H., “Kahn-Type Tear Tests and Crack Toughnessof Aluminum Sheet,” Metals Research and Standards, April 1964, pp. 151155.4For referenced ASTM st

15、andards, 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 website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken

16、, PA 19428-2959, United States.4.2 Tear test specimens should be fractured using anymechanical test machine capable of quasi-static loading at acrosshead speed of 0.05 in./min (1.3 mm/min) or less.5. Significance and Use5.1 The significance of the tear test is similar to that of thenotch-tensile tes

17、t, and its primary usefulness is as an indicatorof toughness or as a ranking test as described in Test MethodE 338 and Practice B 646.5.1.1 This test method provides a comparative measure ofresistance of aluminum alloys and products to unstable fractureoriginating from the presence of crack-like str

18、ess concentra-tors. This test method is not intended to provide an absolutemeasure of resistance to crack propagation that might be usedin the design of a structure.5.2 Values of the energies required to initiate and propagatecracks in tear specimens are determined by measuring orintegrating the app

19、ropriate areas under the test curve developedduring the test.5.3 The unit propagation energy (UPE) is the primary resultof the tear test. This value provides a measure of the combi-nation of strength and ductility that permits a material to resistcrack growth under either elastic or plastic stresses

20、. The UPEvalue normally will exhibit greater scatter than conventionaltensile or yield strength values. In order to establish a reason-able estimate of average properties, it is recommended thatreplicate specimens be tested for each metal condition beingevaluated. The UPE value has significance as a

21、 relative indexof fracture toughness.5.4 The ratio of the tear strength to the tensile yield strengthis a measure of notch toughness comparable to the notch-yieldratio from notch-tensile tests carried out in accordance withTest Method E 338. It is of value in relative ranking ofmaterials with regard

22、 to their toughness.2,35.5 The numerical results of the test are dependent upon thespecimen size and geometry, although specimen thicknessesover the range of 0.063 in. (1.6 mm) to 0.100 in. (2.5 mm) havenot shown a significant effect on tear strength (TS) and unitpropagation energy (UPE).5These valu

23、es may exhibit a depen-dency to thickness when the specimen thickness is outside ofthis stated range and care shall be taken when using this data.5.6 The tear test can serve the following purposes:5.6.1 In the research and development of materials, to studythe effects of variables of composition, pr

24、ocessing, heat treat-ment, etc.5.6.2 In service evaluation, to compare the relative crackpropagation resistance of a number of aluminum alloys orproducts that are otherwise equally suitable for an application.5.6.3 For specifications of material acceptance and manu-facturing quality control when the

25、re is a sound basis forestablishing a minimum acceptable tear test property, that is,UPE.5.7 The reliability of the tear test has been well establishedby developing reasonably good correlations2,3between tear testdata and fracture toughness test data of aluminum alloys andproducts, as determined in

26、accordance with Practices B 645,B 646 and Test Method E 399. Limited data suggest that thetest may be sensitive to crosshead rates above 0.5 in./min.6. Apparatus6.1 The test shall be conducted with a tension testingmachine conforming to the requirements of Practices E4.6.2 The device for transmittin

27、g force to the specimen shallbe such that force axis coincides with the root of the edgenotch. A satisfactory arrangement for force application incor-porates clevises having hardened pins that pass through theholes in the specimen. The diameter of the hardened pins isslightly smaller than that of th

28、e holes. Spacing washers of thenecessary thickness shall be used to center the specimen in theclevises. A typical arrangement is shown in Fig. 1.6.3 Displacement at the notch tip is measured by displace-ment gages or similar devices that are mounted on thespecimen or the clevis at a point correspond

29、ing to the force axisof the specimen. The devices shall be calibrated in accordancewith Practice E83. For ductile materials, it is recommendedthat the displacement gages have a travel capability of at least0.5 in.6.4 The use of crosshead displacement is not recommendedbecause of the fact that all de

30、formation in the test fixtures andspecimen clevis is then included in the displacement measure-ment and contributes to the apparent initiation and propagationenergies measured. If crosshead displacement is used, the datacannot be compared directly with data measured in accordancewith 6.2 unless a ca

31、libration comparison with a number ofstandard materials is conducted.6.5 Because testing machine stiffness can influence the datarecording in the tear test, the use of a relatively stiff machine is5Kaufman, J. G., and Reedy, J. F., “Description and Procedure for MakingKahn-Type Tear Tests,”Alcoa Res

32、earch Laboratory Report 9-M 681, Feb. 10, 1966. FIG. 1 Tear Test Specimen Clevis ArrangementB 871 01 (2007)2recommended. Further, it is recommended that for consistencyof data, the same testing machine or machines be used for alltests that are intended for direct comparison and relative ratingof a g

33、roup of materials. If comparisons are to be made betweendifferent machines in one location or among several locations/organizations, it is recommended that a series of calibrationtests be run on a group of materials with a range of toughnesslevels.6.5.1 If rapid fracture of tear specimens is regular

34、ly ob-served, as described in 9.6.1, this is an indication that a stiffertesting machine and related apparatus is required to minimizeextraneous energy release and deformation during the tear test.7. Test Specimens7.1 The design of the standard specimen is shown in Fig. 2.The dimensions shall be as

35、indicated and pin loading shall beused. Specimen Types 1 and 2 are considered “standard” sizes.Types 3, 4 and 5 have the same dimensions as Types 1 and 2,except for thickness, and are used only in instances where it isdesirable to test the full thickness of products up to 0.250 in.(6.35 mm) in thick

36、ness. For specimens that are machined tothickness, equal amounts of material are typically removedfrom each side.7.1.1 For products thicker than 0.100 in. (2.54 mm), andespecially for those thicker than 0.250 in. (6.35 mm), it isrecommended that 0.100 in. (2.54 mm) thick specimens bemachined from th

37、e appropriate orientations to maximize theease of comparison with data for other products and lots.7.2 The minimum specimen thickness shall be 0.040 in. (1mm). Type 1 specimen dimensions are used for this thickness.7.3 Measure the specimen thickness, B, to the nearest0.0005 in. (0.013 mm) at not les

38、s than three positions betweenthe machined notch and the back of the specimen and recordthe average value. If the variation about the average is greaterthan 62 %, the specimen should be repaired or discarded.Measure the distance between the notch root and the back edgeof the specimen, the net sectio

39、n width, to the nearest 0.001 in.(0.025 mm) and record. Measure the notch root radius to thenearest 0.00025 in. (0.006 mm) and record.7.3.1 The sharpness of the machined notch is critical to thetear specimen, and special care is required to prepare the notch.For each specimen, the notch root radius

40、and notch locationwith respect to pin hole centers shall be measured prior totesting, and specimens that do not meet the requirements ofFig. 2 shall be discarded or reworked.8. Specimen Orientation8.1 The tear properties of aluminum alloys usually dependon the specimen orientation and the direction

41、in which theforce is applied relative to the grain flow of the specimen. Thespecimen orientation and loading direction should be identifiedby the following systems:8.1.1 The reference direction for rectangular shapes areindicated in Fig. 3 and are suitable for sheet, plate, extrusions,forgings and o

42、ther shapes of nonsymmetrical grain flow.8.1.2 The reference direction for certain cylindrical shapeswhere the longitudinal axis is the predominant grain flow areindicated in Fig. 4. The terminology in Fig. 4 is applicable torolled, drawn, extruded, or forged round rod.8.2 Atwo letter code is used i

43、n Figs. 3 and 4 to describe thespecimen orientations and loading directions. The first letterdesignates the direction of loading, while the second letterdesignates the direction of crack propagation. The most com-monly used specimen orientations are the L-T, T-L, and S-Lforrectangular shapes in 8.1.

44、1 and L-R, C-R, and R-L forcylindrical shapes in 8.1.2.9. Procedure9.1 Ensure the specimen and test clevises are clean and freeof dirt and lubrication.9.2 Place the specimen in the test fixtures of the type shownin Fig. 1 and apply a small preload of 50 to 100 lb (220 to 440N) to the specimen.9.3 Mo

45、unt a displacement gage on the specimen or fixturesto monitor the displacement of the specimen during testing.9.4 TestingConduct the test so that the crosshead dis-placement is between 0.05 in./min (1.3 mm/min) and 0.10in./min (2.5 mm/min). Monitor the displacement using a devicesimilar to that desc

46、ribed in 6.3. Record the force and displace-ment to determine the maximum force and energies required tofail the specimen. A typical test curve is shown in Fig. 5. Thetest should be stopped when the test force decreases to 1 to 2 %of the force range.9.5 Fracture Appearance and MannerThe appearance o

47、fthe fracture is valuable subsidiary information and shall benoted for each specimen. Representative types of fracture areshown in Fig. 6. Type A is considered “normal”; that is, thecrack path did not deviate more than 10 from the test plane.Fractures other than“ normal” should be noted with appropr

48、iatecautionary notes about the validity of the data. If the fractureoccurs in the direction of loading, Type C, or through the pinhole, Type D, the test is invalid and measurement of energiesshould not be performed. In some cases, the fracture will occurrapidly during all or part of the propagation

49、of the crack portionof the test. Depending on the speed and accuracy of theType of Specimen T E W D L1 0.064 0.438 1.438 0.3125/0.3130 2142 0.100 0.438 1.438 0.3125/0.3130 2143 0.125 0.438 1.438 0.3125/0.3130 2144 0.187 0.438 1.438 0.3125/0.3130 2145 0.250 0.438 1.438 0.3125/0.3130 214FIG. 2 Tear Test SpecimenB 871 01 (2007)3recording equipment, the results of this portion of the test couldbe misleading and should be noted on the report.9.6 Validity CriteriaThe following are intended to pro-vide guidance when analyzing the test result and pertain to thetype of fr