SIST EN ISO 14577-1:2015

SLOVENSKI STANDARD
01-oktober-2015
1DGRPHãþD
SIST EN ISO 14577-1:2004
Kovinski materiali - Instrumentirano vtiskanje pri preskušanju trdote in drugih
lastnosti materialov - 1. del: Preskusna metoda (ISO 14577-1:2015)
Metallic materials - Instrumented indentation test for hardness and materials parameters
- Part 1: Test method (ISO 14577-1:2015)
Metallische Werkstoffe - Instrumentierte Eindringprüfung zur Bestimmung der Härte und
anderer Werkstoffparameter - Teil 1: Prüfverfahren (ISO 14577-1:2015)
Matériaux métalliques - Essai de pénétration instrumenté pour la détermination de la
dureté et de paramètres des matériaux - Partie 1: Méthode d'essai (ISO 14577-1:2015)
Ta slovenski standard je istoveten z: EN ISO 14577-1:2015
ICS:
77.040.10 Mehansko preskušanje kovin Mechanical testing of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 14577-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2015
ICS 77.040.10 Supersedes EN ISO 14577-1:2002
English Version
Metallic materials - Instrumented indentation test for hardness
and materials parameters - Part 1: Test method (ISO 14577-
1:2015)
Matériaux métalliques - Essai de pénétration instrumenté Metallische Werkstoffe - Instrumentierte Eindringprüfung
pour la détermination de la dureté et de paramètres des zur Bestimmung der Härte und anderer Werkstoffparameter
matériaux - Partie 1 : Méthode d'essai (ISO 14577-1:2015) - Teil 1: Prüfverfahren (ISO 14577-1:2015)
This European Standard was approved by CEN on 16 April 2015.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14577-1:2015 E
worldwide for CEN national Members.

Contents
Page
European foreword .3

European foreword
This document (EN ISO 14577-1:2015) has been prepared by Technical Committee ISO/TC 164 “Mechanical
testing of metals” in collaboration with Technical Committee ECISS/TC 101 “Test methods for steel (other
than chemical analysis)” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by January 2016, and conflicting national standards shall be withdrawn at
the latest by January 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 14577-1:2002.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 14577-1:2015 has been approved by CEN as EN ISO 14577-1:2015 without any modification.

INTERNATIONAL ISO
STANDARD 14577-1
Second edition
2015-07-15
Metallic materials — Instrumented
indentation test for hardness and
materials parameters —
Part 1:
Test method
Matériaux métalliques — Essai de pénétration instrumenté pour la
détermination de la dureté et de paramètres des matériaux —
Partie 1: Méthode d’essai
Reference number
ISO 14577-1:2015(E)
©
ISO 2015
ISO 14577-1:2015(E)
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
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CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2015 – All rights reserved

ISO 14577-1:2015(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Symbols and designations . 2
4 Principle . 4
5 Testing machine . 4
6 Test piece . 5
7 Procedure. 5
8 Uncertainty of the results . 8
9 Test report . 9
Annex A (normative) Materials parameters determined from the force/indentation depth
data set .11
Annex B (informative) Types of control use for the indentation process .24
Annex C (normative) Machine compliance and indenter area function .25
Annex D (informative) Notes on diamond indenters .27
Annex E (normative) Influence of the test piece surface roughness on the accuracy of
the results .28
Annex F (informative) Correlation of indentation hardness H to Vickers hardness .29
IT
Annex G (normative) Drift and creep rate determination .31
Annex H (informative) Estimation of uncertainty of the calculated values of hardness and
materials parameters .33
Annex I (normative) Calculation of radial displacement correction .43
Bibliography .45
ISO 14577-1:2015(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 3, Hardness testing.
This second edition cancels and replaces the first edition (ISO 14577-1:2002), which has been
technically revised.
ISO 14577 consists of the following parts, under the general title Metallic materials — Instrumented
indentation test for hardness and materials parameters:
— Part 1: Test method
— Part 2: Verification and calibration of testing machines
— Part 3: Calibration of reference blocks
— Part 4: Test method for metallic and non-metallic coatings
iv © ISO 2015 – All rights reserved

ISO 14577-1:2015(E)
Introduction
Hardness has typically been defined as the resistance of a material to permanent penetration by
another harder material. The results obtained when performing Rockwell, Vickers, and Brinell tests are
determined after the test force has been removed. Therefore, the effect of elastic deformation under the
indenter has been ignored.
ISO 14577 (all parts) has been prepared to enable the user to evaluate the indentation of materials by
considering both the force and displacement during plastic and elastic deformation. By monitoring the
complete cycle of increasing and removal of the test force, hardness values equivalent to traditional
hardness values can be determined. More significantly, additional properties of the material, such as
its indentation modulus and elasto-plastic hardness, can also be determined. All these values can be
calculated without the need to measure the indent optically. Furthermore, by a variety of techniques, the
instrumented indentation test allows to record hardness and modulus depth profiles within a, probably
complex, indentation cycle.
ISO 14577 (all parts) has been written to allow a wide variety of post-test data analysis.
INTERNATIONAL STANDARD ISO 14577-1:2015(E)
Metallic materials — Instrumented indentation test for
hardness and materials parameters —
Part 1:
Test method
1 Scope
This part of ISO 14577 specifies the method of instrumented indentation test for determination of
hardness and other materials parameters for the following three ranges:
— macro range: 2 N ≤ F ≤ 30 kN;
— micro range: 2 N > F; h > 0,2 µm;
— nano range: h ≤ 0,2 µm.
For the nano range, the mechanical deformation strongly depends on the real shape of indenter tip and the
calculated material parameters are significantly influenced by the contact area function of the indenter
used in the testing machine. Therefore, careful calibration of both instrument and indenter shape is
required in order to achieve an acceptable reproducibility of the materials parameters determined with
different machines.
The macro and micro ranges are distinguished by the test forces in relation to the indentation depth.
Attention is drawn to the fact that the micro range has an upper limit given by the test force (2 N) and a
lower limit given by the indentation depth of 0,2 µm.
The determination of hardness and other material parameters is given in Annex A.
At high contact pressures, damage to the indenter is possible. For this reason in the macro range,
hardmetal indenters are often used. For test pieces with very high hardness and modulus of elasticity,
permanent indenter deformation can occur and can be detected using suitable reference materials. It is
necessary that its influence on the test result be taken into account.
This test method can also be applied to thin metallic and non-metallic coatings and non-metallic
materials. In this case, it is recommended that the specifications in the relevant standards be taken into
account (see also 6.3 and ISO 14577-4).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 14577-2:2015, Metallic materials — Instrumented indentation test for hardness and materials
parameters — Part 2: Verification and calibration of testing machines
ISO/IEC Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
ISO 14577-1:2015(E)
3 Symbols and designations
For the purposes of this document, the symbols and designations in Table 1 shall be applied (see also
Figure 1 and Figure 2).
Table 1 — Symbols and designations
Symbol Designation Unit
A (h ) Projected area of contact of the indenter at distance h from the tip mm
p c c
A (h) Surface area of the indenter at distance h from the tip mm
s
C Indentation creep %
IT
Total measured compliance of the contact (dh/dF tangent to the force removal nm/mN
C
T
curve at maximum test force)
C Instrument compliance nm/mN
F
C Compliance of the contact after correction for machine compliance nm/mN
S
E Indentation modulus of the test piece GPa
IT
Reduced plane strain modulus of the contact (combination of test piece and GPa
E
r
indenter plane strain moduli)
F Test force N
F Maximum test force N
max
h Indentation depth under applied test force mm
h Depth of the contact of the indenter with the test piece at F mm
c max
h Maximum indentation depth at F mm
max max
h Permanent indentation depth after removal of the test force mm
p
Point of intersection of the tangent c to curve b at F with the indentation mm
max
h
r
depth-axis as identified on Figure 1
H Indentation hardness GPa
IT
HM Martens hardness GPa
Martens hardness, determined from the slope of the increasing GPa
HM
s
force/indentation depth curve
GPa
HM
diff Martens hardness, determined from the first derivative of h vs F
ν Poisson’s ratio of the test piece
s
r Radius of spherical indenter mm
R Indentation relaxation %
IT
W Elastic reverse deformation work of indentation N⋅m
elast
W Total mechanical work of indentation N⋅m
total
Cone semi-angle or angle of facet to the indentation axis for pyramidal °
α
indenters
Maximum angle between the contact surface and the indenter for calculation °
θ
of radial displacement
η Ratio W /W %
IT elast total
NOTE 1 To avoid very long numbers, the use of multiples or sub-multiples of the units is permitted.
2 2
NOTE 2 The continued use of the unit N/mm is allowed. 1 MPa = 1 N/mm .
2 © ISO 2015 – All rights reserved

ISO 14577-1:2015(E)
Key
a application of the test force
b removal of the test force
c tangent to curve b at F
max
Figure 1 — Schematic representation of the test procedure
Key
a indenter
b surface of residual plastic indentation in a test piece that has a “perfectly plastic” response
c surface of test piece at maximum indentation depth and test force
θ maximum angle between the test piece surface and the indenter
Figure 2 — Schematic representation of the cross section of indentation
in the case of material “sink-in”
ISO 14577-1:2015(E)
4 Principle
Continuous recording of the force and the depth of indentation permits the determination of hardness
and material properties (see Figure 1 and Figure 2). An indenter consisting of a material harder than the
material under test shall be used. The following shapes and materials can be used:
a) diamond indenter shaped as an orthogonal pyramid with a square base and with an angle α = 68°
between the axis of the diamond pyramid and one of the faces (Vickers pyramid; see Figure A.1);
b) diamond pyramid with triangular base (e.g. modified Berkovich pyramid with an angle α = 65,27°
between the axis of the diamond pyramid and one of the faces; see Figure A.1);
c) hardmetal ball (especially for the determination of the elastic behaviour of materials);
d) diamond spherical tipped conical indenter.
This part of ISO 14577 does not preclude the use of other indenter geometries; however, care should be taken
in interpreting the results obtained with such indenters. Other materials like sapphire can also be used.
NOTE Due to the crystal structure of diamond, indenters that are intended to be spherical are often
polyhedrons and do not have an ideal spherical shape.
The test procedure can either be force-controlled or displacement-controlled. The test force, F, the
corresponding indentation depth, h, and time are recorded during the whole test procedure. The result
of the test is the data set of the test force and the relevant indentation depths as a function of time (see
Figure 1 and Annex B).
For a reproducible determination of the force and corresponding indentation depth, the zero point for
the force/indentation depth measurement shall be assigned individually for each test (see 7.3).
Where time-dependent effects are being measured
— using the force-controlled method, the test force is kept constant over a specified period and the
change of the indentation depth is measured as a function of the holding time of the test force (see
Figures A.3 and B.1), and
— using the indentation depth controlled method, the indentation depth is kept constant over a
specified period and the change of the test force is measured as a function of the holding time of the
indentation depth (see Figures A.4 and B.2).
The two kinds of control mentioned give essentially different results in the segment b of the curves in
Figure B.1 a) and Figure B.2 b) or in Figure B.1 b) and Figure B.2 a).
5 Testing machine
5.1 The testing machine shall have the capability of applying predetermined test forces or displacements
within the required scope and shall fulfil the requirements of ISO 14577-2.
5.2 The testing machine shall have the capability of measuring and reporting applied force, indentation
displacement and time throughout the testing cycle.
5.3 The testing machine shall have the capability of compensating for the machine compliance and of
utilizing the appropriate indenter area function (see Annex C and ISO 14577-2:2015, 4.5 and 4.6).
5.4 Indenters for use with testing machines can have various shapes, as specified in ISO 14577-2 (for
further information on diamond indenters, see Annex D).
5.5 The testing machine shall operate at a temperature within the permissible range specified in 7.1
and shall maintain its calibration within the limits specified in ISO 14577-2:2015, Clause 4.
4 © ISO 2015 – All rights reserved

ISO 14577-1:2015(E)
6 Test piece
6.1 The test shall be carried out on a region of the test surface that allows the determination of the
force/indentation depth curve for the respective indentation range within the required uncertainty. The
contact area shall be free of fluids or lubricants except where this is essential for the performance of the
test, in which case, this shall be described in detail in the test report. Care shall be taken that extraneous
matter (e.g. dust particles) is not incorporated into the contact.
Generally, provided the surface is free from obvious surface contamination, cleaning procedures should
be avoided. If cleaning is required, it shall be limited to the following methods to minimize damage:
— application of a dry, oil-free, filtered gas stream;
— application of a subliming particle stream of CO (but keeping the surface temperature above
the dew point);
— rinsing with a solvent (which is chemically inert to the test piece) and then setting it to dry.
If these methods fail and the surface is sufficiently robust, wipe the surface with a lint-free tissue soaked
in solvent to remove trapped dust particles, after which, the surface shall be rinsed in a solvent as above.
Ultrasonic methods are known to create or increase damage to surfaces and coatings and should only
be used with caution.
For an explanation concerning the influence of the test piece roughness on the uncertainty of the results,
see Annex E. Surface finish has a significant influence on the test results.
The test surfaces shall be normal to the test force direction. It is recommended that the test surface tilt
is less than 1°. Tilt should be included in the uncertainty calculation.
6.2 Preparation of the test surface shall be carried out in such a way that any alteration of the surface
hardness and/or surface residual stress (e.g. due to heat or cold-working) is minimized.
Due to the small indentation depths in the micro and nano range, special precautions shall be taken during
the test piece preparation. A polishing process that is suitable for the particular materials shall be used.
6.3 The test piece thickness shall be large enough (or indentation depth small enough) such that the
test result is not influenced by the test piece support. The test piece thickness should be at least 10 × the
indentation depth or 3 × the indentation diameter (see 7.7), whichever is greater.
When testing coatings, the coating thickness should be considered as the test piece thickness. For testing
coatings, see ISO 14577-4.
NOTE The above are empirically based limits. The exact limits of influence of support on test piece depend on
the geometry of the indenter used and the materials properties of the test piece and support.
7 Procedure
7.1 The temperature of the test shall be recorded. Typically, tests are carried out in the range of ambient
temperatures between 10 °C and 35 °C.
The temperature stability during a test is more important than the actual test temperature. Any
calibration correction applied shall be reported along with the additional calibration uncertainty.
It is recommended that tests, particularly in the nano and micro ranges, be performed in controlled
conditions, in the range (23 ± 5) °C and (45 ± 10) % relative humidity.
ISO 14577-1:2015(E)
The individual tests, however, shall be carried out at stable temperature conditions because of the
requirement of high depth measuring accuracy. This means that
— the test pieces shall have reached the ambient temperature before testing,
— the testing machine shall have reached a stable working temperature (operating manual should
be consulted),
— the ambient, instrument, and test temperature shall be within the range for which the machine
calibration is valid, and
— other external influences causing temperature changes during individual test have been controlled.
To minimize thermally induced displacement drift, the temperature of the testing machine shall
be adequately maintained over the time period of one testing cycle, or a displacement drift shall be
measured and corrected. A decision tree to assist in estimating the drift during the experiment is shown
in Figure 3. If the drift rate is significant, the displacement data shall be corrected by measuring the
drift rate during a hold at an applied force as close to zero force as is practicable or during a hold at a
suitable place in the force removal curve (see ISO 14577-2:2015, Annex G and 4.3.3). If a contact in the
fully elastic regime can be obtained, a hold at initial contact is preferred. In this way, material influences
(creep, visco-plasticity, cracking) can be minimized. The uncertainty due to the drift, or in the drift
correction used, shall be reported.
NOTE To determine the drift of surface referenced instruments, elastic contact between the reference and
the surface is sufficient; contact of the indenter with the surface is not required and is not recommended.
Figure 3 — Decision tree to assist in estimating thermal drift using a constant force hold period
7.2 The test piece shall be firmly supported such that there is no significant increase in the testing
machine compliance. The test piece shall either be placed on a support that is rigid in the direction of
indentation or be fixed in a suitable test piece holder. The contact surfaces between test piece support
and test piece holder shall be free from extraneous matter, which can increase the compliance (reduce the
stiffness) of the test piece support.
6 © ISO 2015 – All rights reserved

ISO 14577-1:2015(E)
NOTE If the sample is supported by materials or mounting methods other than those used when determining
the machine compliance, then the different elastic response of these materials and mounting methods can cause
additional compliance.
7.3 The zero point for the measurement of the force/indentation depth curve shall be assigned
individually to each test data set by one of the methods following. It represents the first touch of the
indenter with the test piece surface. The uncertainty in the zero-point shall be reported. The uncertainty
in the assigned zero point should not exceed 1 % of maximum indentation displacement for the macro
and micro ranges. The zero point uncertainty for the nano range can exceed 1 %, in which case the value
shall be estimated.
a) Method 1: The zero-point is calculated by extrapolation of a fitted function to the force-application
curve (see curve a in Figure 1); a power law fit with the exponent as a fitting parameter constrained
to be 1 ≤ m ≤ 2 is recommended. The fit shall be applied to values within the range from the first
recorded data point to not more than 10 % of the maximum indentation depth. The first recorded
data point shall be less than 2 % of F or less than 5 % of the maximum indentation depth and the
max
fitted data shall not contain a change in indentation response such as the onset of plastic yielding.
It is recommended that the first recorded data point be as close to the zero point as possible. The
uncertainty of the calculated zero point results from the fit parameters, the fitting function and the
length of extrapolation. The uncertainty is calculated as the standard error of the intercept of the
fit with the zero force axes.
NOTE 1 The first part of the indentation curve (for instance up to 5 % of h ) can be affected by vibration
max
or other noise.
b) Method 2: The zero-point is the touch point determined from the first increase of either the test
force or the contact stiffness. At this touch point, the step size in force or displacement shall be small
enough such that the zero point uncertainty is less than the limit required.
−4
NOTE 2 Typical small force steps values for the macro range are 10 F and for the micro and nano
max
range less than 5 µN.
7.4 The testing cycle can be either force-controlled or displacement-controlled. The controlled
parameters can vary either continuously or step by step. A full description of all parts of the testing cycle
shall be stated in the report, including the following:
a) nature of the control (i.e. force or displacement control and whether a stepped or continuous change
in the controlled parameters);
b) maximum force (or displacement);
c) force application (or displacement) function;
d) length and position of each hold period;
e) data logging frequency (or number of data points).
NOTE An example cycle for nano and micro ranges is the following: force application time, 30 s; hold at F ,
max
30 s; force removal 10 s. A 60 s hold period to measure thermal drift can also be required (see Annex G).
The time taken for a test can influence the results obtained. In order to obtain comparable test results
the time taken for the test shall be taken into account.
7.5 The test force shall be applied, without shock or vibration that can significantly affect the test
results, until either the applied test force or the indentation displacement attains the specified value.
Force and displacement shall be recorded at the time intervals stated in the report.
During the determination of the touch point of the indenter with the test piece, the approach speed of
the indenter should be low in order that the mechanical properties of the surface are not changed by the
ISO 14577-1:2015(E)
impact. For micro range indentations, it should not exceed 2 µm/s. Typical micro/nano range approach
speeds are 10 nm/s to 20 nm/s or less during final approach.
NOTE At present, the exact limit of the approach speed for the macro range is not known. It is recommended
that users report the approach speed.
Force/indentation depth/time data sets are directly comparable only if the same indenter and test cycle
(profile) is used. The test profile shall be specified in terms of either applied test force or indentation
displacement as a function of time. The two most common cycles are
a) constant applied test force rate, and
b) constant indentation displacement rate.
The rate of applied test force removal is subject to the requirements that: a sufficient number of data
points for any subsequent analysis are recorded during applied test force removal, and that the total
creep and any residual creep rate is within acceptable limits (see Annex G).
If the drift rate is significant (see 7.1 and Annex G), the force and depth data shall be corrected by use of
the measured drift rate.
7.6 Throughout the test, the testing machine shall be protected from shock and vibration, air movements
and variations in temperature, which can significantly influence the test result.
7.7 It is important that the test results are not affected by the presence of an interface, free surface or
by any plastic deformation introduced by a previous indentation in a series. The effect of any of these
depends on the indenter geometry and the materials properties of the test piece. Indentations shall be
at least three times their indentation diameter away from interfaces or free surfaces and the minimum
distance between indentations shall be at least five times the largest indentation diameter.
The indentation diameter is the in-plane diameter at the surface of the test piece of the circular impression
of an indent created by a spherical indenter. For non-circular impressions, the indentation diameter is
the diameter of the smallest circle capable of enclosing the indentation. Occasional cracking can occur
at the corners of the indentation. When this occurs, the indentation diameter should enclose the crack.
The minimum distances specified are best applicable to ceramic materials and metals such as iron and its
alloys. For other materials, it is recommended that separations of at least 10 indentation diameters be used.
If in doubt, it is recommended that the values from the first indentation are compared with those from
subsequent indentations in a series. If there is a significant difference, the indentations might be too
close and the distance should be increased. A factor of two increases in separation is suggested.
It can be desirable to measure thin coatings in cross-section (e.g. to avoid problems due to surface
roughness). In this case, there might not be enough coating thickness to meet the minimum spacing
requirements as specified above. Smaller spacing can be used if there is experimental evidence that this
does not significantly influence the force/indentation depth/time data sets with respect to correctly
spaced indentations on similar test pieces with thicker coatings.
8 Uncertainty of the results
A complete evaluation of the uncertainty shall be carried out in accordance with ISO/IEC Guide 98-3. A
detailed description of two methods of evaluation of uncertainty is given in Annex H.
Method 1: This approach for determining uncertainty considers only those uncertainties associated
with the overall measurement performance of the testing machine with respect to reference blocks
(abbreviated as CRM below). These performance uncertainties reflect the combined effect of all of the
separate uncertainties (indirect verification). When using this approach, it is important that, during
the test, the individual machine components are operating in the exactly same way and within the
tolerances of the indirect validation being used to estimate the uncertainties.
8 © ISO 2015 – All rights reserved

ISO 14577-1:2015(E)
Method 2: This approach calculates a combined uncertainty from individual contributions. These can be
grouped into random and systematic uncertainties. Individual parameters can contribute one or both
types of uncertainty to the total measurement uncertainty. For example, the uncertainty in measured
displacement can have a random component due to the resolution of the scale used and vibrational
noise, etc., plus a systematic component due to the displacement sensor calibration uncertainty. The
following sources of uncertainty shall be considered:
— zero point assignation;
— measurement of force and displacement (i.e. noise floor, including effects of ambient vibrations and
magnetic field strength changes etc.);
— fitting of the force-removal curve;
— thermal drift rate;
— contact area due to surface roughness;
— force, displacement;
— testing machine compliance;
— indenter area function calibration values;
— calibration drift due to uncertainty in temperature of testing machine and time since last calibration;
— tilt of test surface.
It might not always be possible to individually quantify all of the identified contributions to the random
uncertainty. In this case, an estimate of standard uncertainty can be obtained from the statistical
analysis of repeated indentations into the test material. Care should be taken that systematic standard
uncertainties that can contribute to the random standard uncertainty are not counted twice (see
ISO/IEC Guide 98-3:2008, Clause 4).
A guideline for the evaluation of the uncertainty in determination of hardness and materials parameters
(Annex A) is given in Annex H.
9 Test report
The test report shall include the following information:
a) reference to this part of ISO 14577, i.e. ISO 14577-1:2015;
b) all details necessary for identifying the test piece;
c) material and shape of the indenter and, where used, the detailed area function of the indenter;
d) testing cycle (control method and full description of the cycle profile); this should include
1) set point values,
2) rates and times of force or displacement,
3) position and length of hold points, and
4) data logging frequency or number of points logged for each section of the cycle;
e) result obtained, the total expanded uncertainty and the number of tests;
f) method and functional form of any fit used for the determination of the zero-point;
g) all operations not specified by this part of ISO 14577, or regarded as optional;
ISO 14577-1:2015(E)
h) details of any occurrence that can have affected the results;
i) temperature of the test;
j) date and time of test;
k) analysis methods;
l) if required, all agreed additional information including determined values from the measured
force/indentation depth curve and detailed information about the uncertainty budget.
NOTE It is frequently desirable to describe in the test report the location of the indentation on the test piece
and the unique identifier of the instrument or the specific instrument configuration used to perform the test.
10 © ISO 2015 – All rights reserved

ISO 14577-1:2015(E)
Annex A
(normative)
Materials parameters determined from the force/indentation
depth data set
A.1 General
Instrumented indentation force/indentation depth data sets can be used to derive a number of
materials parameters.
NOTE Using more complex test procedures, like extended cycles (load-partial unload) in an indentation that
increases incrementally in force to obtain many unloading curves referenced to the same zero point, it is possible
to get information about contact compliance at different test forces at a single test site.
1)
A.2 Martens hardness
A.2.1 Determination of Martens hardness, HM
Martens hardness, HM, is measured under applied test force. Martens hardness is determined from the
values given by the force/indentation depth curve during the increasing of the test force, preferably
after reaching the specified test force. Martens hardness includes the plastic and elastic deformation,
thus this hardness value can be calculated for all materials.
Martens hardness is defined for the Vickers and Berkovich pyramidal indenters shown in Figure A.1. It
is not defined for the Knoop indenter or for ball indenters.
Martens hardness is defined as the test force, F, divided by A (h), the surface area of the indenter
s
penetrating beyond the zero-point of the contact, and is expressed in MPa, as given in Formula (A.1).
F
HM= (A.1)
Ah()
s
-3
NOTE The formula gives HM in MPa. To get HM in GPa a factor of 10 is required.
Values of Martens hardness are comparable only if obtained at the same depth.
The designation of angle α for the Vickers and Berkovich indenters is shown in Figure A.1.
The surface area A (h) for the Vickers indenter is given in Formula (A.2) and for the Berkovich indenter
s
in Formula (A.3).
a) Vickers indenter
4×sinα
Ah()= ×h (A.2)
s
cos α
b) Berkovich indenter
33××tanα
Ah()= ×h (A.3)
s
cosα
1) Former designation Universal hardness HU, see Reference [1].
ISO 14577-1:2015(E)
2 2
NOTE 1 A (h) = 26,43 × h for the Vickers indenter (2α = 136°), A (h) = 26,43 × h for the original Berkovich
s s
indenter (α = 65,03°) and A (h) = 26,98 × h for the modified Berkovich indenter (α = 65,27°).
s
NOTE 2 Most Berkovich indenters in use have, in fact, a modified Berkovich geometry.
For an indentation depth h < 6 µm, the area function of the indenter cannot be assumed to be that
of the perfect theoretical shape, since all pointed indenters have some degree of rounding at the tip
and spherically ended indenters (spherical and conical) are unlikely to have a uniform radius. The
determination of the exact area function for a given indenter is particularly important for these
indentation depths, but is beneficial for all indentation depths (see ISO 14577-2:2015, 4.5.1 and 4.6).
For an indentation depth h < 6 µm, the real surface area, A (h), shall be used for the calculation; see
s
Annex C and Reference [2].
NOTE 3 The area function, A (h), is normally expressed as a mathematical function relating the surface area
s
to the distance from the tip of the indenter. Where the area function cannot be described by a relatively simple
(cubic or polynomial) mathematical function, then an estimate can be made either graphically or by using a look-
up table. Alternatively, a different mathematical function can be used to describe different parts of the indenter
[21]
or a spline function adopted.
For the micro and macro ranges, the test forces, 1 N, 2,5 N, 5 N, and 10 N and their decimal multiples
should be chosen for easy comparison of hardness values.
For certain applications, it can be useful to hold the specified test force over a specific time interval. The
duration of the hold period of the test force should be documented to an accuracy of 0,5 s
...