1、Designation: B871 01 (Reapproved 2013)Standard Test Method forTear Testing of Aluminum Alloy Products1This standard is issued under the fixed designation B871; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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. (6.3
3、5 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 th
4、e 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 B645, B646 and Test Method E399.1.5 The values stated in
5、 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 safety
6、 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4B557 Test Methods for Tension Testing Wrought and CastAluminum- and Magnesium-Alloy ProductsB645 Practice for Linear-Elastic PlaneStrain FractureToughness Testing
7、of Aluminum AlloysB646 Practice for Fracture Toughness Testing of AluminumAlloysE4 Practices for Force Verification of Testing MachinesE83 Practice for Verification and Classification of Exten-someter SystemsE338 Test Method of Sharp-Notch Tension Testing of High-Strength Sheet Materials (Withdrawn
8、2010)5E399 Test Method 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 int
9、egrating the area under 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
10、 curve from the point 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 ben
11、ding stress that the 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 B557.3.1.6 unit propagation energy, UPE (FL1)the amount ofenergy requi
12、red to propagate a crack 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-co
13、rded for analysis.1This 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 May 1, 2013. Published August 2013. Originallyapproved in 1996. Last previous edition approved in 2
14、007 as B87101 (2007). DOI:10.1520/B0871-01R13.2Kaufman, 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 Stan
15、dards, April 1964, pp. 151155.4For 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 website.5The last approved version of t
16、his historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesNOTICE: This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International (www.astm.org)
17、for the latest information14.2 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 test, a
18、nd its primary usefulness is as an indicatorof toughness or as a ranking test as described in Test MethodE338 and Practice B646.5.1.1 This test method provides a comparative measure ofresistance of aluminum alloys and products to unstable fractureoriginating from the presence of crack-like stress co
19、ncentra-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 appropria
20、te 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. The
21、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 relat
22、ive 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 E338. It is of value in relative ranking of materialswith regard to the
23、ir 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).6These values may
24、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, processin
25、g, heattreatment, 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 there is a s
26、ound 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 accordanc
27、e with Practices B645,B646 and Test Method E399. Limited data suggest that the testmay 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 transmitting force to t
28、he 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 the holes. Spa
29、cing 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 corresponding to the f
30、orce 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 deformation in
31、 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 accordance6Kaufman, J. G., and Reedy, J. F
32、., “Description and Procedure for MakingKahn-Type Tear Tests,” Alcoa Research Laboratory Report 9-M 681, Feb. 10, 1966. FIG. 1 Tear Test Specimen Clevis ArrangementB871 01 (2013)2with 6.2 unless a calibration comparison with a number ofstandard materials is conducted.6.5 Because testing machine stif
33、fness can influence the datarecording in the tear test, the use of a relatively stiff machine isrecommended. 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 group of mate
34、rials. 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 regularlyobserved,
35、as described in 9.6.1, this is an indication that astiffer testing machine and related apparatus is required tominimize extraneous energy release and deformation duringthe tear test.7. Test Specimens7.1 The design of the standard specimen is shown in Fig. 2.The dimensions shall be as indicated and p
36、in 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 thickness. For speci
37、mens 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 the appropriate o
38、rientations 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 less than three po
39、sitions 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 section width, to the
40、 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 and notch locat
41、ionwith 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 in which thefor
42、ce 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 other shapes of
43、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 A two letter code is used in Figs. 3 and
44、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-L forrectangular shapes in 8.1.1 and L-R, C-
45、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 Mount a displac
46、ement gage on the specimen or fixturesto monitor the displacement of the specimen during testing.9.4 TestingConduct the test so that the crosshead displace-ment is between 0.05 in./min (1.3 mm/min) and 0.10 in./min(2.5 mm/min). Monitor the displacement using a device similarto that described in 6.3.
47、 Record the force and displacement todetermine the maximum force and energies required to fail thespecimen. A typical test curve is shown in Fig. 5. The testshould be stopped when the test force decreases to 1 to 2 % ofthe force range.9.5 Fracture Appearance and MannerThe appearance ofthe fracture i
48、s valuable subsidiary information and shall benoted for each specimen. Representative types of fracture areshown in Fig. 6. Type A is considered “normal”; that is, theType of Speci-menTEW 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 2
49、144 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 SpecimenB871 01 (2013)3crack path did not deviate more than 10 from the test plane.Fractures other than“ normal” should be noted with appropriatecautionary 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 of the crack portion
