1、Designation: E2546 15Standard Practice forInstrumented Indentation Testing1This standard is issued under the fixed designation E2546; 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 parenthese
2、s indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice defines the basic steps of InstrumentedIndentation Testing (IIT) and establishes the requirements,accuracies, and capabilities needed by an
3、instrument to suc-cessfully perform the test and produce the data that can be usedfor the determination of indentation hardness and other mate-rial characteristics. IIT is a mechanical test that measures theresponse of a material to the imposed stress and strain of ashaped indenter by forcing the in
4、denter into a material andmonitoring the force on, and displacement of, the indenter as afunction of time during the full loading-unloading test cycle.1.2 The operational features of an IIT instrument, as well asrequirements for Instrument Verification (Annex A1), Stan-dardized Reference Blocks (Ann
5、ex A2) and Indenter Require-ments (Annex A3) are defined. This practice is not intended tobe a complete purchase specification for an IIT instrument.1.3 With the exception of the non-mandatory Appendix X4,this practice does not define the analysis necessary to deter-mine material properties. That an
6、alysis is left for other testmethods. Appendix X4 includes some basic analysis tech-niques to allow for the indirect performance verification of anIIT instrument by using test blocks.1.4 Zero point determination, instrument compliance deter-mination and the indirect determination of an indenters are
7、afunction are important parts of the IIT process. The practicedefines the requirements for these items and includes non-mandatory appendixes to help the user define them.1.5 The use of deliberate lateral displacements is not in-cluded in this practice (that is, scratch testing).1.6 The values stated
8、 in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.7 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 and h
9、ealth practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E3 Guide for Preparation of Metallographic SpecimensE74 Practice of Calibration of Force-Measuring Instrumentsfor Verifying the Force Indication of Testing MachinesE92 T
10、est Method for Vickers Hardness of Metallic Materials(Withdrawn 2010)3E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE384 Test Method for Knoop and Vickers Hardness ofMaterialsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1
11、875 Test Method for Dynamic Youngs Modulus, ShearModulus, and Poissons Ratio by Sonic ResonanceE1876 Test Method for Dynamic Youngs Modulus, ShearModulus, and Poissons Ratio by Impulse Excitation ofVibration2.2 American Bearing Manufacturers Association Stan-dard:ABMA/ISO 3290-1 Rolling Bearings- Ba
12、lls-Part 1: SteelMetal Balls42.3 ISO Standards:ISO 14577-1, -2, -3, -4 Metallic MaterialsInstrumentedIndentation Tests for Hardness and Material Properties5ISO 376 Metallic MaterialsCalibration of Force-ProvingInstruments for the Verification of Uniaxial Testing Ma-chines53. Terminology3.1 Definitio
13、ns of Terms Specific to This Standard:1This practice is under the jurisdiction ofASTM Committee E28 on MechanicalTesting and is the direct responsibility of Subcommittee E28.06 on IndentationHardness Testing.Current edition approved Oct. 1, 2015. Published December 2015. Originallyapproved in 2007.
14、Last previous edition approved in 2007 as E2546071. DOI:10.1520/E2546-15.2For 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 A
15、STM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American Bearing Manufacturers Association (ABMA), 2025M Street, NW Suite 800 Washington, DC 20036, http:/www.americanbearings.org.5Available from American National Standards Institute (AN
16、SI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1 contact stiffness, nthe instantaneous elastic
17、 responseof the material over the area of contact with the indenter.3.1.1.1 DiscussionContact stiffness can be determinedfrom the slope of line 3 in Fig. 1.3.1.2 force displacement curve, na common plot of theforce applied to an indenter and the resultant depth of penetra-tion.3.1.2.1 DiscussionThis
18、 plot is generated from data col-lected during the entire loading and unloading cycle. (See Fig.1.)3.1.3 indentation radius a, nthe in-plane radius, at thesurface of the test piece, of the circular impression of an indentcreated by a spherical indenter.3.1.3.1 DiscussionFor non-circular impressions,
19、 the in-dentation radius is the radius of the smallest circle capable ofenclosing the indentation. The indentation radius is normallyused as a guide for spacing of indentations.3.1.4 indenter area function , nmathematical functionthat relates the projected (cross-section) area of the indenter tipto
20、the distance from the apex of the tip as measured along thecentral axis.3.1.5 instrument compliance, nthe flex or reaction of theload frame, actuator, stage, indenter, anvil, etc., that is theresult of the application of a test force to the sample.3.1.6 instrumented indentation test (IIT), nan inden
21、tationtest where the force applied to an indenter and the resultantdisplacement of the indenter into the sample are recordedduring the loading and unloading process for post test analysis.3.1.7 nominal area function, narea function determinedfrom measurement of the gross indenter geometry.3.1.8 refi
22、ned area function, narea function determinedindirectly by a technique such as the one described in Appen-dix X3.3.1.9 test cycle, na series of operations at a single locationon the test sample specified in terms of either applied test forceor displacement as a function of time.3.1.9.1 DiscussionThe
23、test cycle may include any of thefollowing operations: approach of the indenter towards the testsample, singular or multiple loading, dwell, and unloadingcycles.3.1.10 test data, nfor this practice it will consist, at theminimum, of a set of related force/displacement/time datapoints.3.1.11 zero poi
24、nt, nthe force-displacement-time referencepoint when the indenter first contacts the sample and the forceis zero.3.1.11.1 DiscussionA course zero point is an approximatevalue used as part of an analysis to determine a refined value.3.2 Indentation Symbols and Designations (see Fig. 2 andTable 1):4.
25、Summary of Practice4.1 This practice defines the details of the IIT test and therequirements and capabilities for instruments that perform IITtests. The necessary components are defined along with therequired accuracies required to obtain useful results. Verifica-tion methods are defined to insure t
26、hat the instruments areperforming properly. It is intended that ASTM (or other) TestMethods will refer to this practice when defining differentcalculations or algorithms that determine one or more materialcharacteristics that are of interest to the user.5. Significance and Use5.1 IIT Instruments are
27、 used to quantitatively measurevarious mechanical properties of thin coatings and othervolumes of material when other traditional methods of deter-mining material properties cannot be used due to the size orcondition of the sample. This practice will establish the basicrequirements for those instrum
28、ents. It is intended that IITbasedtest methods will be able to refer to this practice for the basicrequirements for force and displacement accuracy,reproducibility, verification, reporting, etc., that are necessaryfor obtaining meaningful test results.5.2 IIT is not restricted to specific test force
29、s, displacementranges, or indenter types. This practice covers the requirementsfor a wide range of nano, micro, and macro (see ISO 14577-1)indentation testing applications. The various IIT instrumentsare required to adhere to the requirements of the practice withintheir specific design ranges.6. App
30、aratus6.1 GeneralThe force, displacement and time are simul-taneously recorded during the full sequence of the test. Ananalysis of the recorded data must be done to yield relevantinformation about the sample. When available, relevantASTMtest methods for the analysis should be followed for compara-ti
31、ve results.NOTE 1The user is encouraged to refer to the manufacturersinstruction manual to understand the exact details of the tests and analysisperformed.6.2 Testing InstrumentThe instrument shall be able to beverified according to the requirements defined in AnnexA1 andhave the following features.
32、1. Increasing test force2. Removal of the test force3. Tangent to curve 2 at FmaxFIG. 1 IIT Procedure Shown SchematicallyE2546 1526.2.1 Test Forces/DisplacementsThe instrument shall beable to apply operator selectable test forces or displacementswithin its usable range. The controlled parameters can
33、 varyeither continuously or step by step. The application of the testforce shall be smooth and free from any unintended vibrationsor abnormalities that could adversely affect the results. Theapproach, loading, and data acquisition rates shall be controlledto the extent that is required to obtain mea
34、ningful estimates offorce and displacement uncertainties at the zero point. Theestimated uncertainty in the force at the zero point shall notexceed 1 % of the maximum test force (Fmax)or2N,whichever is greater. The estimated uncertainty in the displace-ment at the zero point should not exceed 1 % of
35、 the maximumindenter displacement (hmax) or 2 nm, whichever is greater. Ifthe estimated uncertainty in the displacement at the zero pointis larger than both criteria, its value and the influence of itsvalue on reported mechanical properties shall be noted in thetest report. See Appendix X1 for infor
36、mation on how todetermine the zero point.6.2.2 Sample PositioningThe positioning of the samplebeing tested relative to the centerline of the test force is criticalto obtaining good results. The testing instrument shall bedesigned to allow the centerline of the test force to be normalto the sample su
37、rface at the point of indentation.6.2.3 IndentersIndenters normally consists of a contact tipand a suitable holder. The tip should have a hardness andmodulus that significantly exceeds the materials being tested.The holder shall be manufactured to support the contact pointwithout any unpredictable d
38、eflections that could affect the testresults. The holder shall allow proper mounting in the actuatorand position the contact point correctly for the application ofthe test force. The contact tip and holder could be a one ormulti-piece design. A variety of indenter shapes, such aspyramids, cones, and
39、 spheres, can be used for IIT Testing.Annex A3 defines the requirements for the most commonlyused indenters. Whenever they are used the requirements ofAnnexA3 shall be followed. Other indenter shapes can be usedprovided they are defined in a standardized Method or de-scribed in the test report.NOTE
40、2The nominal indenter geometry, as described in Annex A3,may be sufficiently accurate for a given analysis. In many cases, however,a refined area function that more accurately represents the shape of theindenter used may be necessary to provide the desired results (see A3.7).6.2.4 Imaging Device (Op
41、tional)In applications where itis desirable to accurately locate the indentation point on thesample or observe the indent, an imaging device such as anoptical or atomic force microscope may prove helpful. Thedevice should be mounted such that locations can be identifiedquickly and accurately.6.3 Dat
42、a Storage and Analysis CapabilitiesThe apparatusshall have the following capabilities:6.3.1 Force/Displacement/Time MeasurementAcquire andstore raw force, displacement and time data during each test.6.3.2 Data CorrectionWhen necessary, conversion of theraw data defined in 6.3.1 to corrected force (F
43、), displacement(h), and time (t) data as defined in 3.2. The conversion shallNOTE 1The symbols shown are the same for pointed and spherical indenters.FIG. 2 Schematic Cross-Section of an IIT IndentationTABLE 1 Symbols and DesignationsSymbol Designation Unit Angle, specific to shape of pyramidal inde
44、nter(see Annex A3)a Radius of indentation (see 3.1.3)mR Radius of spherical indenter (see Annex A3)F Test force applied to sample NFmaxMaximum value of F Nh Indenter displacement into the sample mhmaxMaximum value of h mhcDepth over which the indenter and specimen arein contact during the force appl
45、icationmhpPermanent recovered indentation depth afterremoval oftest forcemAsSurface area of indenter in contact with material m2ApProjected (cross section) area of indenter atdepth hcm2hrPoint of intersection of line 3 with the h axis (seeFig. 1)mS Contact stiffness N/mt Time relative to the zero po
46、int sE2546 153consider at least the following parameters: Zero point determi-nation (see Appendix X1), instrument compliance (see Appen-dix X2) and thermal drift.6.3.3 Indenter Shape FunctionUtilize an appropriate in-denter shape function if necessary (see Appendix X3).6.3.4 Test Result Generation:6
47、.3.4.1 Perform the desired analysis on the raw or correcteddata to obtain useful test results. When available, relevantASTM or ISO 14577 test methods should be used.6.3.4.2 Determine indentation modulus (EIT) according tothe Test Method defined in Appendix X4 or another methodthat produces similar r
48、esults.7. Test Piece7.1 Surface FinishThe surface finish of the sample willdirectly affect the test results. The test should be performed ona flat specimen with a polished or otherwise suitably preparedsurface. Any contamination will reduce the precision andaccuracy of the test. The user should cons
49、ider the indent sizewhen determining the proper surface finish.7.2 Surface PreparationThe preparation of the surfaceshall be done in a way that minimizes alteration of thecharacteristic of the material to be evaluated.7.3 Sample ThicknessThe thickness of the material to beanalyzed may be a critical factor in the ability to obtain thedesired results. The test piece thickness shall be large enough,or indentation depth small enough, such that the test result isnot influenced by the test piece support. The test piecethickness
