1、Designation: E384 16E384 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
2、 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 U.S. Department of Defense.1. Scope*1.1 This test method covers determination of the microinde
3、ntation hardness of materials.1.2 This test method covers microindentation tests made with Knoop and Vickers indenters under test forces in the range from9.8 10-3 to 9.8 N (1 to 1000 gf).1.3 This test method includes an analysis of the possible sources of errors that can occur during microindentatio
4、n testing andhow these factors affect the precision, bias, repeatability, and reproducibility of test results.1.4 Information pertaining to the requirements for direct verification and calibration of the testing machine and the requirementsfor the manufacture and calibration of Vickers and Knoop ref
5、erence hardness test blocks are in Test Method E92.NOTE 1While Committee E04 is primarily concerned with metals, the test procedures described are applicable to other materials.1.5 UnitsThe values stated in SI units are to be regarded as standard. No other units of measurement are included in thisst
6、andard.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.1.7 This i
7、nternational standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT)
8、Committee.2. Referenced Documents2.1 ASTM Standards:2C1326 Test Method for Knoop Indentation Hardness of Advanced CeramicsC1327 Test Method for Vickers Indentation Hardness of Advanced CeramicsE3 Guide for Preparation of Metallographic SpecimensE7 Terminology Relating to MetallographyE92 Test Method
9、 For Vickers Hardness of Metallic MaterialsE140 Hardness Conversion Tables for Metals Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness,Superficial Hardness, Knoop Hardness, Scleroscope Hardness, and Leeb HardnessE175 Terminology of MicroscopyE177 Practice for Use of the Terms
10、 Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE766 Practice for Calibrating the Magnification of a Scanning Electron MicroscopeE1268 Practice for Assessing the Degree of Banding or Orientation of Microstructur
11、esE2554 Practice for Estimating and Monitoring the Uncertainty of Test Results of a Test Method Using Control Chart TechniquesE2587 Practice for Use of Control Charts in Statistical Process Control1 This test method is under the jurisdiction of ASTM Committee E04 on Metallography and is the direct r
12、esponsibility of Subcommittee E04.05 on MicroindentationHardness Testing. With this revision the test method was expanded to include the requirements previously defined in E28.92, Standard Test Method for Vickers HardnessTesting of Metallic Material that was under the jurisdiction of E28.06Current e
13、dition approved Feb. 1, 2016June 1, 2017. Published April 2016August 2017. Originally approved in 1969. Last previous edition approved in 20102016 asE384 11E384 16.1. DOI: 10.1520/E0384-1610.1520/E0384-172 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Ser
14、vice at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document 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 previo
15、us version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM 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 Chang
16、es section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 ISO Standard:3ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories3. Terminology3.1 Definitions
17、For definitions of terms used in this test method, see Terminology E7.3.2 Definitions of Terms Specific to This Standard:3.2.1 calibrating, vdetermining the values of the significant parameters by comparison with values indicated by a referenceinstrument or by a set of reference standards.3.2.2 Knoo
18、p hardness number, HK, nan expression of hardness obtained by dividing the force applied to the Knoop indenterby the projected area of the permanent impression made by the indenter.3.2.3 Knoop indenter, na rhombic-based pyramidal-shaped diamond indenter with edge angles of /A = 172 30 and / B= 130 0
19、 (see Fig. 1).3.2.4 microindentation hardness test, na hardness test using a calibrated machine to force a diamond indenter of specificgeometry into the surface of the material being evaluated, in which the test forces range from 1 to 1000 gf (9.8 10-3 to 9.8 N),and the indentation diagonal, or diag
20、onals, are measured with a light microscope after load removal; for any microindentationhardness test, it is assumed that the indentation does not undergo elastic recovery after force removal.NOTE 2Use of the term microhardness should be avoided because it implies that the hardness, rather than the
21、force or the indentation size, is verylow.3.2.5 verifying, vchecking or testing the instrument to assure conformance with the specification.3.2.6 Vickers hardness number, HV, nan expression of hardness obtained by dividing the force applied to a Vickers indenterby the surface area of the permanent i
22、mpression made by the indenter.3.2.7 Vickers indenter, na square-based pyramidal-shaped diamond indenter with face angles of 136 (see Fig. 2).3.3 FormulaeThe formulae presented in 3.3.1 3.3.4 for calculating microindentation hardness are based upon an ideal testerand conditions. The measured value o
23、f the microindentation hardness of a material is subjected to several sources of errors. Basedon Eq 1-9, variations in the applied force, geometrical variations between diamond indenters, and human errors in measuringindentation lengths will affect the precision of the calculated material hardness.
24、The magnitude of the error that variations of eachof these parameters have on the calculated value of a microindentation measurement is discussed in Section 10.3.3.1 For Knoop hardness tests, in practice, test loads are in grams-force and indentation diagonals are in micrometers. TheKnoop hardness n
25、umber is calculated using the following:HK51.00031033P/A p!51.00031033P/cp 3d2! (1)or3 Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.org.FIG. 1 Knoop IndenterE384 172HK5142293P/d2 (2)cp 5
26、tan /B22tan/A2(3)where:P = force, gf,d = length of long diagonal, m,Ap = projected area of indentation, m 2/A = included longitudinal edge angle, 172 30/B = included transverse edge angle, 130 0 (see Fig. 1 and,cp = indenter constant relating projected area of the indentation to the square of the le
27、ngth of the long diagonal, ideally0.07028.3.3.2 The Knoop hardness, kgf/mm2 is determined as follows:HK514.2293P1/d12 (4)where:P1 = force, kgf, andd1 = length of long diagonal, mm.3.3.3 The Knoop hardness reported with units of GPa is determined as follows:HK50.0142293P2/d22 (5)where:P2 = force, N,
28、andd2 = length of the long diagonal of the indentation, mm.3.3.4 For the Vickers hardness test, in practice, test loads are in grams-force and indentation diagonals are in micrometers. TheVickers hardness number is calculated as follows:HV51.00031033P/As 52.00031033Psin/2!/d2 (6)orHV51854.43P/d2 (7)
29、where:P = force, gf,FIG. 2 Vickers IndenterE384 173As = 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/mm2 is determined as follows:HV51.85443P1/d12 (8)where:P1 = force, kgf, and
30、d1 = mean diagonal length of the indentations, mm.3.3.6 The Vickers hardness reported with units of GPa is determined as follows:HV50.00185443P2/d22 (9)where:P2 = force, N, andd2 = mean diagonal length of the indentations, mm.3.4 Equations for calculating % Error and Repeatability for periodic verif
31、ication is determined as follows:E 5100Sd 2drefdref D (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 5100Sdmax2dmind D(11)where:R = repeatability in performance of the periodic v
32、erification,dmax = the longest diagonal length measurement on the standardized test block, m,dmin = the shortest diagonal length measurement on the standardized test block, m, andd = the measured mean diagonal length in m.4. Summary of Test Method4.1 In this test method, a hardness number is determi
33、ned based on the formation of a very small indentation by application ofa relatively low force, in comparison to traditional bulk indentation hardness tests.4.2 A Knoop or Vickers indenter, made from diamond of specific geometry, is pressed into the test specimen surface under anapplied force in the
34、 range of 1 to 1000 gf using a test machine specifically designed for such work.4.3 The size of the indentation is measured using a light microscope equipped with a filar type eyepiece, or other type ofmeasuring device (see Terminology E175).4.4 The Knoop hardness number is based upon the force divi
35、ded by the projected area of the indentation. The Vickers hardnessnumber is based upon the force divided by the surface area of the indentation.4.5 It is assumed that elastic recovery does not occur when the indenter is removed after the loading cycle, that is, it is assumedthat the indentation reta
36、ins the shape of the indenter after the force is removed, but this is not always true. In Knoop testing, it isassumed that the ratio of the long diagonal to the short diagonal of the impression is the same as for the indenter, 7.114, but thisis not always true due to elastic recovery.5. Significance
37、 and Use5.1 Hardness tests have been found to be very useful for materials evaluation, quality control of manufacturing processes andresearch and development efforts. Hardness, although empirical in nature, can be correlated to tensile strength for many metals andalloys, and is also an indicator of
38、machinability, wear resistance, toughness and ductility.5.2 Microindentation tests are utilized to evaluate and quantify hardness variations that occur over a small distance. Thesevariations may be intentional, such as produced by localized surface hardening, for example, from shot blasting, cold dr
39、awing,flame hardening, induction hardening, etc., or from processes such as carburization, nitriding, carbonitriding, etc.; or, they may beunintentional variations due to problems, such as decarburization, localized softening in service, or from compositional/microstructural segregation problems. Lo
40、w test forces also extend hardness testing to materials too thin or too small forE384 174macroindentation tests. Microindentation tests permit hardness testing of specific phases or constituents and regions or gradientstoo small for evaluation by macroindentation tests.5.3 Because microindentation h
41、ardness tests will reveal hardness variations that commonly exist within most materials, a singletest value may not be representative of the bulk hardness. Vickers tests at 1000 gf can be utilized for determination of the bulkhardness, but, as for any hardness test, it is recommended that a number o
42、f indents are made and the average and standard deviationare calculated, as needed or as required.5.4 Microindentation hardness testing is generally performed to quantify variations in hardness that occur over small distances.To determine these differences requires a very small physical indentation.
43、 Testers that create indents at very low test forces mustbe carefully constructed to accurately apply the test forces exactly at the desired location and must have a high-quality opticalsystem to precisely measure the diagonal (or diagonals) of the small indents. Test forces in the upper range of th
44、e force rangedefined in 1.2 may be used to evaluate bulk hardness. In general, theVickers indenter is better suited for determining bulk (average)properties as Vickers hardness is not altered by the choice of the test force, from 25 to 1000 gf, because the indent geometry isconstant as a function of
45、 indent depth. The Knoop indentation, however, is not geometrically identical as a function of depth andthere will be variations in Knoop hardness, particularly at test forces 1 kgf, see Test Method E92 for the recommended notation.9.3 Examples of the calculation of measurement uncertainty are given
46、 in Test Method E92.10. Precision and Bias10.1 The precision and bias of microindentation hardness measurements depend on strict adherence to the stated test procedureand are influenced by instrumental and material factors and indentation measurement errors.FIG. 3 Minimum Recommended Spacing for Kno
47、op and Vickers IndentationsE384 17810.2 The consistency of agreement for repeated tests on the same material is dependent on the homogeneity of the material,reproducibility of the hardness tester, and consistent, careful measurement of the indents by a competent operator.10.3 Instrumental factors th
48、at can affect test results include: accuracy of loading; inertia effects; speed of loading; vibrations;the angle of indentation; lateral movement of the indenter or specimen; and, indentation and indenter shape deviations.10.3.1 Vibrations during indenting will produce larger indentations with the p
49、otential influence of vibrations becoming greateras the force decreases (2, 3).10.3.2 The angle between the indenter and specimen surface should be within 2 of perpendicular. Greater amounts of tiltingmay produce non-uniform indentations and incorrect test results.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 polishi
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