1、Designation: E 399 06e1Standard Test Method forLinear-Elastic Plane-Strain Fracture Toughness KIcofMetallic Materials1This standard is issued under the fixed designation E 399; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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.This standard has been approved for use by agencies of the Department of Defense.e1NOTEEq A3.4 was editorially corrected in
3、 April 2007.1. Scope1.1 This test method covers the determination of fracturetoughness (KIc) of metallic materials under predominantlylinear-elastic, plane-strain conditions using fatigue precrackedspecimens having a thickness of 1.6 mm (0.063 in.) or greater2subjected to slowly, or in special (elec
4、tive) cases rapidly,increasing crack-displacement force. Details of test apparatus,specimen configuration, and experimental procedure are givenin the Annexes.NOTE 1Plane-strain fracture toughness tests of thinner materials thatare sufficiently brittle (see 7.1) can be made using other types ofspecim
5、ens (1).3There is no standard test method for such thin materials.1.2 This test method is divided into two parts. The first partgives general recommendations and requirements for KIctesting. The second part consists of Annexes that give specificinformation on displacement gage and loading fixture de
6、sign,special requirements for individual specimen configurations,and detailed procedures for fatigue precracking. Additionalannexes are provided that give specific procedures for beryl-lium and rapid-force testing.1.3 General information and requirements common to allspecimen configurations:SectionR
7、eferenced Documents 2Terminology 3Stress-Intensity Factor 3.1.1Plane-Strain Fracture Toughness 3.1.2Crack Plane Orientation 3.1.3SectionSummary of Test Method 4Significance and Use 5Significance 5.1Precautions 5.1.1-5.1.5Practical Applications 5.2Apparatus (see also 1.4) 6Tension Machine 6.1Fatigue
8、Machine 6.2Loading Fixtures 6.3Displacement Gage, Measurement 6.4Specimen Size, Configurations, and Preparation (seealso 1.5)7Specimen Size Estimates 7.1Standard and Alternative Specimen Configurations 7.2Fatigue Crack Starter Notches 7.3.1Fatigue Precracking (see also 1.6) 7.3.2Crack Extension Beyo
9、nd Starter Notch 7.3.2.2General Procedure 8Specimen MeasurementsThickness 8.2.1Width 8.2.2Crack Size 8.2.3Crack Plane Angle 8.2.4Specimen TestingLoading Rate 8.3Test Record 8.4Calculation and Interpretation of Results 9Test Record Analysis 9.1Pmax/PQValidity Requirement 9.1.3Specimen Size Validity R
10、equirements 9.1.4Reporting 10Precision and Bias 111.4 Specific requirements related to test apparatus:Double-Cantilever Displacement Gage Annex A1Testing Fixtures Annex A2Bend Specimen Loading Fixture Annex A2.1Compact Specimen Loading Clevis Annex A2.21.5 Specific requirements related to individual
11、 specimenconfigurations:Bend Specimen SE(B) Annex A3Compact Specimen C(T) Annex A4Disk-Shaped Compact Specimen DC(T) Annex A5Arc-Shaped Tension Specimen A(T) Annex A6Arc-Shaped Bend Specimen A(B) Annex A71This test method is under the jurisdiction of ASTM Committee E08 on Fatigueand Fracture and is
12、the direct responsibility of Subcommittee E08.07 on FractureMechanics.Current edition approved Dec. 15, 2006. Published February 2007. Originallyapproved in 1970. Last previous edition approved in 2005 as E 399 05.2For additional information relating to the fracture toughness testing of alumi-inum a
13、lloys, see Practice B 645.3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1.6 Specific requirements related to special test procedures:Fa
14、tigue Precracking KIc Specimens Annex A8Hot-Pressed Beryllium Testing Annex A9Rapid-Force Testing Annex A101.7 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.8 This standard does not purport to address all of thesafety conce
15、rns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4B 909 Guide for Plane Strain Fracture To
16、ughness Testing ofNon-Stress Relieved Aluminum ProductsB 645 Practice for Plane-Strain Fracture Toughness Testingof Aluminum AlloysE4 Practices for Force Verification of Testing MachinesE8 Test Methods for Tension Testing of Metallic MaterialsE 337 Test Method for Measuring Humidity with a Psy-chrom
17、eter (the Measurement of Wet- and Dry-Bulb Tem-peratures)E 456 Terminology Relating to Quality and StatisticsE 1820 Test Method for Measurement of Fracture Tough-nessE 1823 Terminology Relating to Fatigue and Fracture Test-ingE 1921 Test Method for Determination of Reference Tem-perature, To, for Fe
18、rritic Steels in the Transition Range3. Terminology3.1 Definitions:Terminology E 1823 is applicable to this testmethod:3.1.1 stress-intensity factor, K, KI,KII,KIIIFL3/2magnitude of the ideal-crack-tip stress field (a stress-fieldsingularity), for a particular mode of crack displacement, in ahomogen
19、eous, linear-elastic body.3.1.1.1 K is a function of applied force and test specimensize, geometry, and crack size, and has the dimensions of forcetimes length-3/2.3.1.1.2 Values of K for modes I, II, and III are given as:KI5limr0syy2pr!1/2# (1)KII5limr0txy2pr!1/2# (2)KIII5limr0tyz2pr!1/2# (3)where
20、r is the distance directly forward from the crack tip tothe location where the significant stress is calculated.3.1.2 plane-strain fracture toughness, KIcFL-3/2 thecrack-extension resistance under conditions of crack-tip planestrain in Mode I for slow rates of loading under predominantlylinear-elast
21、ic conditions and negligible plastic-zone adjust-ment. The stress intensity factor, KIc, is measured using theoperational procedure (and satisfying all of the validity require-ments) specified in Test Method E 399, that provides for themeasurement of crack-extension resistance at the onset (2% orles
22、s) of crack extension and provides operational definitions ofcrack-tip sharpness, onset of crack extension, and crack-tipplane strain.3.1.2.1 See also definitions of crack-extension resistance,crack-tip plane strain, and mode in Terminology E 1823.3.1.3 crack plane orientationidentification of the p
23、laneand direction of crack extension in relation to the characteristicdirections of the product. A hyphenated code defined inTerminology E 1823 is used wherein the letter(s) preceding thehyphen represents the direction normal to the crack plane andthe letter(s) following the hyphen represents the an
24、ticipateddirection of crack extension (see Fig. 1).3.1.3.1 Wrought Productsthe fracture toughness ofwrought material depends on, among other factors, the orien-tation and propagation direction of the crack in relation to thematerials anisotropy, which depends, in turn, on the principaldirections of
25、mechanical working and grain flow. Orientationof the crack plane shall be identified wherever possible. Inaddition, product form shall be identified (for example,straight-rolled plate, cross-rolled plate, pancake forging, and soforth) along with material condition (for example, annealed,solution tre
26、ated plus aged, and so forth). The user shall bereferred to product specifications for detailed processing infor-mation.3.1.3.2 For rectangular sections, the reference directions areidentified as in Fig. 1(a) and Fig. 1(b), which give examples forrolled plate. The same system is used for sheet, extr
27、usions, andforgings with nonsymmetrical grain flow.L = direction of principal deformation (maximum grain flow)T = direction of least deformationS = third orthogonal direction3.1.3.3 Using the two-letter code, the first letter designatesthe direction normal to the crack plane, and the second letterth
28、e expected direction of crack propagation. For example, inFig. 1(a), the T-L specimen fracture plane normal is in thewidth direction of a plate and the expected direction of crackpropagation is coincident with the direction of maximum grainflow (or longitudinal) direction of the plate.3.1.3.4 For sp
29、ecimens tilted in respect to two of the refer-ence axes as in Fig. 1(b), crack plane orientation is identifiedby a three-letter code. The designation L-TS, for example,indicates the crack plane to be perpendicular to the principaldeformation (L) direction, and the expected fracture directionto be in
30、termediate between T and S. The designation TS-Lmeans that the crack plane is perpendicular to a directionintermediate between T and S, and the expected fracturedirection is in the L direction.3.1.3.5 For cylindrical sections with principal deformationparallel to the longitudinal axis of the cylinde
31、r, the referencedirections are identified as in Fig. 1(c), which depicts a drawn4For 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
32、onthe ASTM website.E39906e12(a) Rectangular SectionsSpecimens Aligned with Reference Directions(b) Rectangular SectionsSpecimens Not Aligned with Reference Directions(c) Cylindrical Bars and TubesL = direction of maximum grain flowR = radial directionC = circumferential or tangential directionFIG. 1
33、 Crack Plane IdentificationE39906e13bar. The same system is useful for extrusions or forged partshaving circular cross section.L = direction of maximum grain flowR = radial directionC = circumferential or tangential direction3.1.3.6 In the case of complex structural shapes, where thegrain flow is no
34、t uniform, specimen location and crack planeorientation shall reference component geometry and be notedon component drawings.3.1.3.7 Non-Wrought Productsfor non-wrought products,specimen location and crack plane orientation shall be definedon the part drawing.The result of a fracture toughness test
35、froma non-wrought product shall not carry an orientation designa-tion.3.1.3.8 Discussionwhen products are to be compared onthe basis of fracture toughness, it is essential that specimenlocation and orientation with respect to product characteristicdirections be comparable and that the results not be
36、 generalizedbeyond these limits.3.2 Definitions of Terms Specific to This Standard:3.2.1 crack mouth opening displacement (CMOD), VmLcomponent of clip gage displacement taken at the crackstarter-notch mouth.3.2.2 stress-intensity factor rate, K(FL-3/2t-1)change instress-intensity factor, K, per unit
37、 time.4. Summary of Test Method4.1 This test method covers the determination of the plane-strain fracture toughness (KIc) of metallic materials byincreasing-force tests of fatigue precracked specimens. Force isapplied either in tension or three-point bending. Details of thetest specimens and experim
38、ental procedures are given in theAnnexes. Force versus crack-mouth opening displacement(CMOD) is recorded either autographically or digitally. Theforce at a 5 % secant offset from the initial slope (correspond-ing to about 2.0 % apparent crack extension) is established bya specified deviation from t
39、he linear portion of the record (1).The value of KIcis calculated from this force using equationsthat have been established by elastic stress analysis of thespecimen configurations specified in this test method. Thevalidity of the KIcvalue determined by this test methoddepends upon the establishment
40、 of a sharp-crack condition atthe tip of the fatigue crack in a specimen having a size adequateto ensure predominantly linear-elastic, plane-strain conditions.To establish the suitable crack-tip condition, the stress-intensity factor level at which specimen fatigue precracking isconducted is limited
41、 to a relatively low value.4.2 The specimen size required for test validity increases asthe square of the materials toughness-to-yield strength ratio.Therefore a range of proportional specimens is provided.5. Significance and Use5.1 The property KIcdetermined by this test method char-acterizes the r
42、esistance of a material to fracture in a neutralenvironment in the presence of a sharp crack under essentiallylinear-elastic stress and severe tensile constraint, such that (1)the state of stress near the crack front approaches tritensileplane strain, and (2) the crack-tip plastic zone is smallcompa
43、red to the crack size, specimen thickness, and ligamentahead of the crack.5.1.1 Variation in the value of KIccan be expected withinthe allowable range of specimen proportions, a/W and W/B. KIcmay also be expected to rise with increasing ligament size.Notwithstanding these variations, however, KIcis
44、believed torepresent a lower limiting value of fracture toughness (for 2 %apparent crack extension) in the environment and at the speedand temperature of the test.5.1.2 Lower values of KIccan be obtained for materials thatfail by cleavage fracture; for example, ferritic steels in theductile-to-britt
45、le transition region or below, where the crackfront length affects the measurement in a stochastic mannerindependent of crack front constraint. The present test methoddoes not apply to such materials and the user is referred to TestMethod E 1921 and E 1820 . Likewise this test method doesnot apply t
46、o high toughness or high tearing-resistance materialswhose failure is accompanied by appreciable amounts ofplasticity. Guidance on testing elastic-plastic materials is givenin Test Method E 1820.5.1.3 The value of KIcobtained by this test method may beused to estimate the relation between failure st
47、ress and cracksize for a material in service wherein the conditions of highconstraint described above would be expected. Backgroundinformation concerning the basis for development of this testmethod in terms of linear elastic fracture mechanics may befound in Refs (1) and (3).5.1.4 Cyclic forces can
48、 cause crack extension at KIvaluesless than KIc. Crack extension under cyclic or sustained forces(as by stress corrosion cracking or creep crack growth) can beinfluenced by temperature and environment. Therefore, whenKIcis applied to the design of service components, differencesbetween laboratory te
49、st and field conditions shall be consid-ered.5.1.5 Plane-strain fracture toughness testing is unusual inthat there can be no advance assurance that a valid KIcwill bedetermined in a particular test. Therefore, compliance with thespecified validity criteria of this test method is essential.5.1.6 Residual stresses can adversely affect the indicatedKQand KIcvalues. The effect can be especially significant forspecimens removed from as-heat treated or otherwise non-stress relieved stock, from weldments, from complex wroughtparts, or from parts with intention
