1、Designation: E 2546 07Standard Practice forInstrumented Indentation Testing1This standard is issued under the fixed designation E 2546; 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 parenthe
2、ses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice defines the basic steps of InstrumentedIndentation Testing (IIT) and establishes the requirements,accuracies, and capabilities needed by a
3、n 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
4、indenter 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 (A
5、nnex 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
6、analysis 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 a
7、reafunction 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 stat
8、ed 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
9、 health 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 Instru-ments for Verifying the Force Indication of Testing Ma-chines
10、E92 Test Method for Vickers Hardness of Metallic Mate-rialsE 384 Test Method for Microindentation Hardness of Ma-terialsE 1875 Test Method for Dynamic Youngs Modulus, ShearModulus, and Poissons Ratio by Sonic ResonanceE 1876 Test Method for Dynamic Youngs Modulus, ShearModulus, and Poissons Ratio by
11、 Impulse Excitation ofVibration2.2 American Bearings Manufacturer Association Stan-dard:ABMA 10-1988 Metal Balls32.3 ISO Standards:ISO 14577-1, -2, -3, -4 Metallic MaterialsInstrumentedIndentation Tests for Hardness and Material Properties4ISO 376 Metallic MaterialsCalibration of Force-ProvingInstru
12、ments for the Verification of Uniaxial Testing Ma-chines43. Terminology3.1 Definitions of Terms Specific to This Standard:1This practice is under the jurisdiction of ASTM Committee E28 on MechanicalTesting and is the direct responsibility of Subcommittee E28.06 on IndentationHardness Testing.Current
13、 edition approved July 15, 2007. Published July 2007.2For 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 ASTM website.3Availab
14、le from American Bearing Manufacturers Association (ABMA), 2025M Street, NW Suite 800 Washington, DC 20036, http:/www.abma-dc.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Har
15、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1 contact stiffness, nthe instantaneous elastic responseof the material over the area of contact with the indenter.Contact stiffness can be determined from the slope of line 3 inFig. 1.3.1.2 force displacement curve, na comm
16、on plot of theforce applied to an indenter and the resultant depth of penetra-tion. This plot is generated from data collected during the entireloading 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 a
17、n indentcreated by a spherical indenter. For non-circular impressions,the indentation radius is the radius of the smallest circlecapable of enclosing the indentation. The indentation radius isnormally used as a guide for spacing of indentations.3.1.4 indenter area function L, nmathematical functiont
18、hat relates the projected (cross-section) area of the indenter tipto 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 for
19、ce to the sample.3.1.6 instrumented indentation test (IIT), nan indentationtest where the force applied to an indenter and the resultantdisplacement of the indenter into the sample is recorded duringthe loading and unloading process for post test analysis.3.1.7 nominal area function, narea function
20、determinedfrom measurement of the gross indenter geometry.3.1.8 refined area function, narea function determinedindirectly by a technique such as the one described inAppendixX3.3.1.9 test cycle, na series of operations at a single locationon the test sample. The cycle is specified in terms of either
21、applied test force or displacement as a function of time. Thetest cycle may include any of the following operations:approach of the indenter towards the test sample, singular ormultiple loading, dwell, and unloading cycles.3.1.10 test data, nfor this practice it will consist, at theminimum, of a set
22、 of related force/displacement/time datapoints.3.1.11 zero point, nthe force-displacement-time referencepoint when the indenter first contacts the sample and the forceis zero. A course zero point is an approximate value used aspart of an analysis to determine a refined value.3.2 Indentation Symbols
23、and Designations (see Fig. 2):Symbol Designation Unita Angle, specific to shape of pyramidal indenter (see Annex A3)a Radius of projected indentation mR Radius of spherical indenter (see Annex A3)F Test force applied to sample NFmaxMaximum value of F Nh Indenter displacement into the sample mhmaxMax
24、imum value of h mhcDepth over which the indenter and specimen are in contactduring the force applicationmhpPermanent recovered indentation depth after removal oftest forcemAsSurface area of indenter in contact with material m2ApProjected (cross section) area of indenter at depth hcm2hrPoint of inter
25、section of line 3 with the h axis (see Fig. 1)mS Contact stiffness N/mt Time relative to the zero point s4. 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
26、with therequired accuracies required to obtain useful results. Verifica-tion methods are defined to insure that 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
27、more materialcharacteristics that are of interest to the user.5. Significance and Use5.1 IIT Instruments are 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
28、 to the size orcondition of the sample. This practice will establish the basicrequirements for those instruments. It is intended that IIT basedtest methods will be able to refer to this practice for the basicrequirements for force and displacement accuracy, reproduc-ibility, verification, reporting,
29、 etc., that are necessary forobtaining meaningful test results.5.2 IIT is not restricted to specific test forces, 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
30、instrumentsare required to adhere to the requirements of the practice withinthe their specific design ranges.6. Apparatus6.1 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 relevantinform
31、ation about the sample. When available, relevant ASTMtest methods for the analysis should be followed for compara-tive results.NOTE 1The user is encouraged to refer to the manufacturers instruc-tion manual to understand the exact details of the tests and analysisperformed.1. Increasing test force2.
32、Removal of the test force3. Tangent to curve 2 at FmaxFIG. 1 IIT Procedure Shown SchematicallyE25460726.2 Testing InstrumentThe instrument shall be able to beverified according to the requirements defined inAnnexA1 andhave the following features.6.2.1 Test Forces/DisplacementsThe instrument shall be
33、able to apply operator selectable test forces or displacementswithin its usable range. The controlled parameters can 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 resul
34、ts. Theapproach, loading, and data acquisition rates shall be controlledto the extent that is required to obtain meaningful 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)
35、 or 2 N, whichever is greater. The estimated uncertainty in the displacementat the zero point should not exceed 1 % of the maximumindenter displacement (hmax) or 2 nm, which ever is greater. Ifthe estimated uncertainty in the displacement at the zero pointis larger than both criteria, its value and
36、the influence of itsvalue on reported mechanical properties shall be noted in thetest report. See Appendix X1 for information 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
37、results. The testing instrument shall bedesigned to allow the centerline of the test force to be normalto the sample surface at the point of indentation.6.2.3 IndentersIndenters normally consists of a contacttip and a suitable holder. The tip should have a hardness andmodulus that significantly exce
38、eds the materials being tested.The holder shall be manufactured to support the contact pointwithout any unpredictable deflections 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. Th
39、e contact tip and holder could be a one ormulti-piece design. A variety of indenter shapes, such aspyramids, cones, and 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. Oth
40、er indenter shapes can be usedprovided they are defined in a standardized Method or de-scribed in the test report.NOTE 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 repre
41、sents the shape of theindenter used may be necessary to provide the desired results (see A3.7).6.2.4 Imaging Device (Optional)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 micros
42、cope may prove helpful. Thedevice should be mounted such that locations can be identifiedquickly and accurately.6.3 Data Storage and Analysis CapabilitiesThe apparatusshall have the following capabilities:6.3.1 Force/Displacement/Time MeasurementAcquireand store raw force, displacement and time data
43、 during eachtest.6.3.2 Data CorrectionWhen necessary, conversion of theraw data defined in 6.3.1 to corrected force (F), displacement(h), and time (t) data as defined in 3.2. The conversion shallconsider at least the following parameters: Zero point determi-nation (see Appendix X1), instrument compl
44、iance (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:6.3.4.1 Perform the desired analysis on the raw or correcteddata to obtain useful test results. When available, relevant
45、ASTM 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 results.7. Test Piece7.1 Surface FinishThe surface finish of the sample willdirectly affect the test results. The test s
46、hould be performed onNOTEThe symbols shown are the same for pointed and spherical indenters.FIG. 2 Schematic Cross-Section of an IIT IndentationE2546073a flat specimen with a polished or otherwise suitably preparedsurface. Any contamination will reduce the precision andaccuracy of the test. The user
47、 should consider 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
48、 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 should be at least 10 times the indentation depth orsix time
49、s greater than the indentation radius; which ever isgreater.8. Procedure8.1 Prepare EnvironmentThe test should be carried outwithin the temperature range defined by the manufacturer.Prior to performing any tests the instrument and the test sampleshall be stabilized to the temperature of the environment.Temperature change during each test should be less than 1.0C.The test environment shall be clean and free from vibrations,electromagnetic interference, or other variations that couldadversely affect the performance of the instrument.
