ASTM E384-17 Standard Test Method for Microindentation Hardness of Materials.pdf

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1、Designation: E384 17Standard Test Method forMicroindentation Hardness of Materials1This standard is issued under the fixed designation E384; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in par

2、entheses 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 U.S. Department of Defense.1. Scope*1.1 This test method covers determination of the microin-dentatio

3、n hardness of materials.1.2 This test method covers microindentation tests madewith Knoop andVickers indenters under test forces in the rangefrom 9.8 10-3to 9.8 N (1 to 1000 gf).1.3 This test method includes an analysis of the possiblesources of errors that can occur during microindentation testinga

4、nd how these factors affect the precision, bias, repeatability,and reproducibility of test results.1.4 Information pertaining to the requirements for directverification and calibration of the testing machine and therequirements for the manufacture and calibration of Vickersand Knoop reference hardne

5、ss test blocks are in Test MethodE92.NOTE 1While Committee E04 is primarily concerned with metals, thetest procedures described are applicable to other materials.1.5 UnitsThe values stated in SI units are to be regardedas standard. No other units of measurement are included in thisstandard.1.6 This

6、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 determine the applica-bility of regulatory limitations prior to use.1.7 This international s

7、tandard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2

8、. Referenced Documents2.1 ASTM Standards:2C1326 Test Method for Knoop Indentation Hardness ofAdvanced CeramicsC1327 Test Method for Vickers Indentation Hardness ofAdvanced CeramicsE3 Guide for Preparation of Metallographic SpecimensE7 Terminology Relating to MetallographyE92 Test Method ForVickers H

9、ardness of Metallic MaterialsE140 Hardness Conversion Tables for Metals RelationshipAmong Brinell Hardness, Vickers Hardness, RockwellHardness, Superficial Hardness, Knoop Hardness, Sclero-scope Hardness, and Leeb HardnessE175 Terminology of MicroscopyE177 Practice for Use of the Terms Precision and

10、 Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE766 Practice for Calibrating the Magnification of a Scan-ning Electron MicroscopeE1268 Practice for Assessing the Degree of Banding orOrientation of MicrostructuresE2554 Practice

11、 for Estimating and Monitoring the Uncer-tainty of Test Results of a Test Method Using ControlChart TechniquesE2587 Practice for Use of Control Charts in StatisticalProcess Control2.2 ISO Standard:3ISO/IEC 17025 General Requirements for the Competenceof Testing and Calibration Laboratories3. Termino

12、logy3.1 DefinitionsFor definitions of terms used in this testmethod, see Terminology E7.3.2 Definitions of Terms Specific to This Standard:1This test method is under the jurisdiction of ASTM Committee E04 onMetallography and is the direct responsibility of Subcommittee E04.05 on Micro-indentation Ha

13、rdness Testing. With this revision the test method was expanded toinclude the requirements previously defined in E28.92, Standard Test Method forVickers Hardness Testing of Metallic Material that was under the jurisdiction ofE28.06Current edition approved June 1, 2017. Published August 2017. Origina

14、llyapproved in 1969. Last previous edition approved in 2016 as E384 16. DOI:10.1520/E0384-172For 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 S

15、ummary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Ha

16、rbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommenda

17、tions issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.1 calibrating, vdetermining the values of the signifi-cant parameters by comparison with values indicated by areference instrument or by a set of reference standards.3.2.2 Knoop hardness number, HK, nan exp

18、ression ofhardness obtained by dividing the force applied to the Knoopindenter by the projected area of the permanent impressionmade by the indenter.3.2.3 Knoop indenter, na rhombic-based pyramidal-shaped diamond indenter with edge angles of /A = 172 30and / B = 130 0 (see Fig. 1).3.2.4 microindenta

19、tion hardness test, na hardness testusing a calibrated machine to force a diamond indenter ofspecific geometry into the surface of the material beingevaluated, in which the test forces range from 1 to 1000 gf (9.810-3to 9.8 N), and the indentation diagonal, or diagonals, aremeasured with a light mic

20、roscope after load removal; for anymicroindentation hardness test, it is assumed that the indenta-tion does not undergo elastic recovery after force removal.NOTE 2Use of the term microhardness should be avoided because itimplies that the hardness, rather than the force or the indentation size, isver

21、y low.3.2.5 verifying, vchecking or testing the instrument toassure conformance with the specification.3.2.6 Vickers hardness number, HV, nan expression ofhardness obtained by dividing the force applied to a Vickersindenter by the surface area of the permanent impression madeby the indenter.3.2.7 Vi

22、ckers indenter, na square-based pyramidal-shapeddiamond indenter with face angles of 136 (see Fig. 2).3.3 FormulaeThe formulae presented in 3.3.1 3.3.4 forcalculating microindentation hardness are based upon an idealtester and conditions. The measured value of the microinden-tation hardness of a mat

23、erial is subjected to several sources oferrors. Based on Eq 1-9, variations in the applied force,geometrical variations between diamond indenters, and humanerrors in measuring indentation lengths will affect the precisionof the calculated material hardness. The magnitude of the errorthat variations

24、of each of these parameters have on thecalculated value of a microindentation measurement is dis-cussed in Section 10.3.3.1 For Knoop hardness tests, in practice, test loads are ingrams-force and indentation diagonals are in micrometers. TheKnoop hardness number is calculated using the following:HK

25、5 1.000 31033 P/Ap! 5 1.000 31033 P/cp3 d2! (1)orHK 5 14229 3 P/d2(2)cp5tan/B22tan/A2(3)where:P = force, gf,d = length of long diagonal, m,Ap= projected area of indentation, m2/A = included longitudinal edge angle, 172 30/B = included transverse edge angle, 130 0 (see Fig. 1and,cp= indenter constant

26、 relating projected area of the inden-tation to the square of the length of the long diagonal,ideally 0.07028.3.3.2 The Knoop hardness, kgf/mm2is determined as fol-lows:HK 5 14.229 3 P1/d12(4)where:P1= force, kgf, andd1= length of long diagonal, mm.FIG. 1 Knoop IndenterE384 1723.3.3 The Knoop hardne

27、ss reported with units of GPa isdetermined as follows:HK 5 0.014229 3 P2/d22(5)where:P2= force, N, andd2= length of the long diagonal of the indentation, mm.3.3.4 For the Vickers hardness test, in practice, test loads arein grams-force and indentation diagonals are in micrometers.The Vickers hardnes

28、s number is calculated as follows:HV 5 1.000 31033 P/As5 2.000 31033 Psin/2!/d2(6)orHV 5 1854.4 3 P/d2(7)where:P = force, gf,As= surface area of the indentation, m2,d = mean diagonal length of the indentation, m, and = face angle of the indenter, 136 0 (see Fig. 2).3.3.5 The Vickers hardness, kgf/mm

29、2is determined asfollows:HV 5 1.8544 3 P1/d12(8)where:P1= force, kgf, andd1= mean diagonal length of the indentations, mm.3.3.6 The Vickers hardness reported with units of GPa isdetermined as follows:HV 5 0.0018544 3 P2/d22(9)where:P2= force, N, andd2= mean diagonal length of the indentations, mm.3.

30、4 Equations for calculating % Error and Repeatability forperiodic verification is determined as follows:E 5 100Sd2 drefdrefD (10)where:E = % error in performance of the periodic verification,d= the measured mean diagonal length in m, anddref= the reported certified mean diagonal length, m.R 5 100Sdm

31、ax2 dmindD(11)where:R = repeatability in performance of the periodicverification,dmax= the longest diagonal length measurement on thestandardized test block, m,dmin= the shortest diagonal length measurement on thestandardized test block, m, andd= the measured mean diagonal length in m.4. Summary of

32、Test Method4.1 In this test method, a hardness number is determinedbased on the formation of a very small indentation by appli-cation of a relatively low force, in comparison to traditionalbulk indentation hardness tests.4.2 A Knoop or Vickers indenter, made from diamond ofspecific geometry, is pres

33、sed into the test specimen surfaceunder an applied force in the range of 1 to 1000 gf using a testmachine specifically designed for such work.4.3 The size of the indentation is measured using a lightmicroscope equipped with a filar type eyepiece, or other typeof measuring device (see Terminology E17

34、5).FIG. 2 Vickers IndenterE384 1734.4 The Knoop hardness number is based upon the forcedivided by the projected area of the indentation. The Vickershardness number is based upon the force divided by the surfacearea of the indentation.4.5 It is assumed that elastic recovery does not occur whenthe ind

35、enter is removed after the loading cycle, that is, it isassumed that the indentation retains the shape of the indenterafter the force is removed, but this is not always true. In Knooptesting, it is assumed that the ratio of the long diagonal to theshort diagonal of the impression is the same as for

36、the indenter,7.114, but this is not always true due to elastic recovery.5. Significance and Use5.1 Hardness tests have been found to be very useful formaterials evaluation, quality control of manufacturing pro-cesses and research and development efforts. Hardness, al-though empirical in nature, can

37、be correlated to tensile strengthfor many metals and alloys, and is also an indicator ofmachinability, wear resistance, toughness and ductility.5.2 Microindentation tests are utilized to evaluate and quan-tify hardness variations that occur over a small distance. Thesevariations may be intentional,

38、such as produced by localizedsurface hardening, for example, from shot blasting, colddrawing, flame hardening, induction hardening, etc., or fromprocesses such as carburization, nitriding, carbonitriding, etc.;or, they may be unintentional variations due to problems, suchas decarburization, localize

39、d softening in service, or fromcompositional/microstructural segregation problems. Low testforces also extend hardness testing to materials too thin or toosmall for macroindentation tests. Microindentation tests permithardness testing of specific phases or constituents and regionsor gradients too sm

40、all for evaluation by macroindentation tests.5.3 Because microindentation hardness tests will revealhardness variations that commonly exist within most materials,a single test value may not be representative of the bulkhardness. Vickers tests at 1000 gf can be utilized for determi-nation of the bulk

41、 hardness, but, as for any hardness test, it isrecommended that a number of indents are made and theaverage and standard deviation are calculated, as needed or asrequired.5.4 Microindentation hardness testing is generally per-formed to quantify variations in hardness that occur over smalldistances.

42、To determine these differences requires a very smallphysical indentation. Testers that create indents at very low testforces must be carefully constructed to accurately apply the testforces exactly at the desired location and must have a high-quality optical system to precisely measure the diagonal

43、(ordiagonals) of the small indents. Test forces in the upper rangeof the force range defined in 1.2 may be used to evaluate bulkhardness. In general, the Vickers indenter is better suited fordetermining bulk (average) properties as Vickers hardness isnot altered by the choice of the test force, from

44、 25 to 1000 gf,because the indent geometry is constant as a function of indentdepth. The Knoop indentation, however, is not geometricallyidentical as a function of depth and there will be variations inKnoop hardness, particularly at test forces 1 kgf, see TestMethod E92 for the recommended notation.

45、9.3 Examples of the calculation of measurement uncertaintyare given in Test Method E92.10. Precision and Bias10.1 The precision and bias of microindentation hardnessmeasurements depend on strict adherence to the stated testprocedure and are influenced by instrumental and materialfactors and indentat

46、ion measurement errors.10.2 The consistency of agreement for repeated tests on thesame material is dependent on the homogeneity of the material,FIG. 3 Minimum Recommended Spacing for Knoop and Vickers IndentationsE384 177reproducibility of the hardness tester, and consistent, carefulmeasurement of t

47、he indents by a competent operator.10.3 Instrumental factors that can affect test results include:accuracy of loading; inertia effects; speed of loading; vibra-tions; the angle of indentation; lateral movement of theindenter or specimen; and, indentation and indenter shapedeviations.10.3.1 Vibration

48、s during indenting will produce larger in-dentations with the potential influence of vibrations becominggreater as the force decreases (2, 3).10.3.2 The angle between the indenter and specimen surfaceshould be within 2 of perpendicular. Greater amounts of tiltingmay produce non-uniform indentations

49、and incorrect testresults.10.4 Material factors that can affect test results include:specimen homogeneity, orientation or texture effects; improperspecimen preparation; low specimen surface reflectivity; and,transparency of the specimen.10.4.1 Residual deformation from mechanical polishingmust be removed, particularly for low-force (200 gf) testing.10.4.2 Distortion of the indentation shape, due to eithercrystallographic or microstructural texture, influences diagonallengths and the validity of the calculated h