ISO 14577-6:2025

International
Standard
ISO 14577-6
First edition
Metallic materials — Instrumented
2025-11
indentation test for hardness and
materials parameters —
Part 6:
Instrumented indentation test at
elevated temperature
Matériaux métalliques — Essai d'indentation instrumenté pour
les paramètres de dureté et de matériaux —
Partie 6: Essai d'indentation instrumenté à température élevée
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 2
3.1 Terms and definitions .2
3.2 Symbols .2
4 Principle . 3
4.1 General .3
4.2 Instrument calibration and verification at elevated temperature .3
4.3 Indenter material selection .3
4.4 Test environment .3
4.5 Indentation creep rate at elevated temperature .3
4.6 Assigning the contact temperature .4
5 Testing machine. 4
5.1 Testing machine capability .4
5.2 Traceable calibration of the contact temperature .5
5.3 Traceable calibration of the test machine at operating temperature .5
5.3.1 Method 1 .5
5.3.2 Method 2 .5
5.4 Indirect validation .5
5.5 Test piece heating . .6
5.6 Test environment .6
5.7 Indenter and frame compliance .6
5.7.1 Indenter geometry .6
5.7.2 Indenter area function and frame compliance .6
5.7.3 Indenter tip material selection .6
5.8 Specific requirements for testing at elevated temperature .7
6 Test pieces . 7
7 Test procedure . 7
8 Results . .10
8.1 Data process and analysis .10
8.2 Indentation hardness at elevated temperature .10
8.2.1 Determination of indentation hardness at elevated temperature, H (T) .10
IT
8.2.2 Designation of indentation hardness at elevated temperature, H (T) .10
IT
8.3 Indentation modulus at elevated temperature .10
8.3.1 Determination of indentation modulus at elevated temperature, E (T).10
IT
8.3.2 Designation of indentation modulus at elevated temperature, E (T).11
IT
9 Uncertainty of results . .11
9.1 Uncertainties for testing at elevated temperature.11
9.2 Error in assigned temperature . 12
9.3 Estimation of uncertainty . 12
10 Test report .13
Annex A (informative) Reactivity of indenter and test piece combinations .15
Annex B (informative) Indenter oxidation onset temperature for various indenter materials .16
Annex C (Normative) Temperature calibration procedure . 17
Bibliography .20

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee
SC 3, Hardness testing.
A list of all parts in the ISO 14577 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
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 increase 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 requirement to measure the indent optically. Furthermore, by a variety of techniques, the instrumented
indentation test is able to generate hardness and modulus values at different indentation depths within the
indentation cycle.
This document has been prepared to enable the user to obtain hardness and other materials parameters
using instrumented indentation testing at elevated temperature. The elastic and plastic properties of
material components at elevated temperature are critical for determining the performance representative
of in-service condition above ambient temperature. Typical applications include hard coatings, nuclear
materials, welded materials, fuel cell materials, aerospace materials, etc. In-service properties of wear
surfaces, cutting tool, high friction contacts are also significant applications.
This document covers the instrumented indentation testing systems with independent heating of both
the indenter and test piece with feedback control and equipped with temperature sensing. This typ
...