EN ISO 14574:2025

SLOVENSKI STANDARD
01-marec-2025
Fina keramika (sodobna keramika, sodobna tehnična keramika) - Mehanske
lastnosti keramičnih kompozitov pri visoki temperaturi - Ugotavljanje nateznih
lastnosti (ISO 14574:2025)
Fine ceramics (advanced ceramics, advanced technical ceramics) - Mechanical
properties of ceramic composites at high temperature - Determination of tensile
properties (ISO 14574:2025)
Hochleistungskeramik - Mechanische Eigenschaften von keramischen
Verbundwerkstoffen bei hoher Temperatur - Bestimmung der Eigenschaften unter Zug
(ISO 14574:2025)
Céramiques techniques - Propriétés mécaniques des céramiques composites à haute
température - Détermination des caractéristiques en traction (ISO 14574:2025)
Ta slovenski standard je istoveten z: EN ISO 14574:2025
ICS:
81.060.30 Sodobna keramika Advanced ceramics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 14574
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2025
EUROPÄISCHE NORM
ICS 81.060.30 Supersedes EN ISO 14574:2016
English Version
Fine ceramics (advanced ceramics, advanced technical
ceramics) - Mechanical properties of ceramic composites
at high temperature - Determination of tensile properties
(ISO 14574:2025)
Céramiques techniques - Propriétés mécaniques des Hochleistungskeramik - Mechanische Eigenschaften
composites à matrice céramique à haute température - von keramischen Verbundwerkstoffen bei hoher
Détermination des caractéristiques en traction (ISO Temperatur - Bestimmung der Eigenschaften unter Zug
14574:2025) (ISO 14574:2025)
This European Standard was approved by CEN on 18 January 2025.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14574:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 14574:2025) has been prepared by Technical Committee ISO/TC 306 "Foundry
machinery" in collaboration with Technical Committee CEN/TC 184 “Advanced technical ceramics” the
secretariat of which is held by DIN.
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 July 2025, and conflicting national standards shall be
withdrawn at the latest by July 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 14574:2016.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 14574:2025 has been approved by CEN as EN ISO 14574:2025 without any modification.

International
Standard
ISO 14574
Second edition
Fine ceramics (advanced ceramics,
2025-01
advanced technical ceramics) —
Mechanical properties of ceramic
composites at high temperature —
Determination of tensile properties
Céramiques techniques — Propriétés mécaniques des composites
à matrice céramique à haute température — Détermination des
caractéristiques en traction
Reference number
ISO 14574:2025(en) © ISO 2025
ISO 14574:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 14574:2025(en)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Apparatus . 4
5.1 Test machine .4
5.2 Load train .4
5.3 Test chamber .4
5.4 Set-up for heating .5
5.5 Strain measurement .5
5.5.1 General .5
5.5.2 Strain gauges.5
5.5.3 Extensometer .5
5.6 Temperature measurement devices .6
5.7 Data recording system .6
5.8 Dimension-measuring devices .6
6 Test specimens . 7
6.1 General .7
6.2 Test specimens commonly used .7
7 Test specimen preparation .11
7.1 Machining and preparation .11
7.2 Number of tests specimens .11
8 Test procedures .12
8.1 Test set-up: Temperature considerations . 12
8.1.1 General . 12
8.1.2 Controlled-temperature zone . 12
8.1.3 Temperature calibration . 12
8.2 Test set-up: Other considerations . 12
8.2.1 Displacement rate . 12
8.2.2 Measurement of test specimen dimensions . 12
8.3 Testing technique . 13
8.3.1 Specimen mounting . 13
8.3.2 Setting of extensometer . 13
8.3.3 Setting of inert atmosphere . 13
8.3.4 Heating of test specimen . 13
8.3.5 Measurements . 13
8.4 Test validity .14
9 Calculation of results . 14
9.1 Test specimen origin .14
9.2 Tensile strength .14
9.3 Strain at maximum tensile force . 15
9.4 Tensile modulus . 15
9.4.1 Calculation of tensile modulus . 15
9.4.2 Calculation of tensile modulus with linear behaviour at the origin .16
9.4.3 Calculation of tensile modulus with non-linear behaviour .16
10 Test report .16
11 Uncertainties . 17
Annex A (informative) Illustration of tensile modulus .18

iii
ISO 14574:2025(en)
Annex B (informative) Calibration method of test temperature by using a cartographic
specimen equipped with thermocouples .21
Bibliography .26

iv
ISO 14574:2025(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 206, Fine ceramics, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 184, Advanced technical
ceramics, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
This second edition cancels and replaces the first edition (ISO 14574:2013), which has been technically
revised.
The main changes are as follows:
— alignment of the terms and definition with the vocabulary standard ISO 20507;
— addition of illustration of tensile modulus in Annex A;
— addition of a calibration method of the test temperature by using a cartographic specimen equipped with
thermocouples in Annex B.
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.

v
International Standard ISO 14574:2025(en)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Mechanical properties of ceramic composites at
high temperature — Determination of tensile properties
1 Scope
This document specifies procedures for determination of the tensile behaviour of ceramic matrix composite
materials with continuous fibre reinforcement at elevated temperature in air, vacuum and inert gas
atmospheres.
This method applies to all ceramic matrix composites with a continuous fibre reinforcement, uni-directional
(1D), bidirectional (2D) and multi-directional (xD, with x> 2), tested along one principal axis of reinforcement
or off axis conditions for 2D and xD materials. This method also applies to carbon-fibre-reinforced carbon
matrix composites (also known as carbon/carbon or C/C).
NOTE In most cases, ceramic matrix composites to be used at high temperature in air are coated with an anti-
oxidation coating.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 3611, Geometrical product specifications (GPS) — Dimensional measuring equipment — Design and
metrological characteristics of micrometers for external measurements
ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Calibration and verification of the force-measuring system
ISO 9513, Metallic materials — Calibration of extensometer systems used in uniaxial testing
ISO 19634, Fine ceramics (advanced ceramics, advanced technical ceramics) — Ceramic composites — Notations
and symbols
ISO 20507, Fine ceramics (advanced ceramics, advanced technical ceramics) — Vocabulary
IEC 60584-1, Thermocouples — Part 1: EMF specifications and tolerances
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 20507, ISO 19634 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
test temperature
T
temperature of the test piece at the centre of the gauge length

ISO 14574:2025(en)
3.2
calibrated length
l
part of the test specimen that has uniform and minimum cross-section area
[SOURCE: ISO 20504:2022, 3.1]
3.3
gauge length
L
initial distance between reference points on the test specimen in the calibrated length
[SOURCE: ISO 20504:2022, 3.2, modified title and definition, words before initiation of the test deleted]
3.4
controlled-temperature zone
part of the calibrated length, including the gauge length, where the temperature is within a range of 50 °C of
the test temperature
3.5
initial cross-section area
S
o
cross-section area of the test specimen within the calibrated length, at room temperature before testing
3.5.1
apparent cross-section area
S
o app
area of the cross section
3.5.2
effective cross-section area
S
o eff
area corrected by a factor, to account for the presence of a coating
3.6
longitudinal deformation
A
increase in the gauge length under a tensile force in the load direction
Note 1 to entry: The longitudinal deformation corresponding to the maximum tensile force is denoted as A .
m
3.7
tensile strain
ε
ratio of deformation to initial gauge length defined as the ratio A/L
Note 1 to entry: The tensile strain corresponding to the maximum tensile force is denoted as ε .
m
3.8
tensile force
F
uniaxial force carried by the test specimen at any time during the tensile test
3.9
tensile stress
σ
tensile force (3.8) supported by the test specimen at any time in the test divided by the initial cross-sectional
area (3.5) such that σ = F/S
o
ISO 14574:2025(en)
3.9.1
apparent tensile stress
σ
app
ratio of the tensile force (3.8) supported by the test piece to the apparent cross-section area (3.5.1)
3.9.2
effective tensile stress
σ
eff
ratio of the tensile force (3.8) carried by the test piece to the effective cross-section area (3.5.2)
3.10
maximum tensile force
F
m
highest force recorded or force at failure during a tensile test
3.11
tensile strength
σ
m
greatest tensile stress (3.9) applied to a test specimen when tested to failure
3.11.1
apparent tensile strength
σ
m app
ratio of the maximum tensile force (3.10) to the apparent cross-section area (3.5.1)
3.11.2
effective tensile strength
σ
m eff
ratio of the maximum tensile force (3.10) to the effective cross-section area (3.5.2)
3.13
tensile modulus
E
slope of the linear section of the stress-strain curve at or near the origin
Note 1 to entry: It is possible that a linear part does not exist or does not start at the origin. The different situations are
then described in the Annex A.
3.13.1
apparent tensile modulus
E
app
slope of the linear part of the stress-strain curve at or near the origin when the apparent tensile stress
(3.9.1) is used
3.13.2
effective tensile modulus
E
eff
slope of the linear part of the stress-strain curve at or near the origin, when the effective tensile stress
(3.9.2) is used
4 Principle
A test specimen of specified dimensions is heated to the test temperature, and loaded in tension. The test is
performed at constant crosshead displacement rate, or constant deformation rate (or constant loading rate).
Force and longitudinal deformation are measured and recorded simultaneously.
NOTE The test duration is limited to reduce creep effects.
When constant loading rate is used in the nonlinear region of the tensile curve, only the tensile strength can
be obtained from the test. In this region, constant crosshead displacement rate or constant deformation rate
is recommended to obtain the complete curve.

ISO 14574:2025(en)
5 Apparatus
5.1 Test machine
The test machine shall be equipped with a system for measuring the force applied to the test specimen that
shall conform to grade 1 or better in accordance with ISO 7500-1.
This should prevail during actual test conditions of, e.g. gas pressure and temperature.
5.2 Load train
The load train configuration shall ensure that the load indicated by the load cell and the load experienced by
the test specimen are the same.
The load train performance, including the alignment system and the force transmitting system, shall not
change because of heating.
The load train shall align the specimen axis with the direction of load application without introducing
bending or torsion in the specimen. The misalignment of the specimen shall be verified at room temperature
and documented. Several standards address this topic but it is recommended to comply with the procedure
−6
described in ISO 17161. The percent bending strain shall not exceed 5 % at an average strain of 500×10 .
The attachment fixtures shall align the test specimen axis with the applied force direction.
The grip design shall prevent the test specimen from slipping.
There are two types of gripping systems:
— hot grips where the grips are in the hot zone of the furnace;
— cold grips where the grips are outside the hot zone.
The choice of gripping system will depend on material, on test specimen design and on alignment
requirements.
The hot grip technique is limited in temperature because of the nature and strength of the materials that
can be used for grips.
In the cold grip technique, a temperature gradient exists between the centre which is at the prescribed
temperature and the ends which are at the same temperature as the grips.
5.3 Test chamber
The test chamber shall be as gas-tight as possible and shall allow proper control of the test specimen
environment in the vicinity of the test specimen during the test.
The installation shall be such that the variation of the load due to the variation of pressure is less than 1 % of
the scale of the load cell being used.
Where a gas atmosphere is used, the gas atmosphere shall be chosen depending on the material to be tested
and on test temperature. The level of pressure shall be chosen depending: on the material to be tested, on
temperature, on the type of gas, and on the type of extensometer.
Where a vacuum chamber is used, the level of vacuum shall not induce chemical and/or physical instabilities
of the test specimen material, and of extensometer rods, when applicable. Primary vacuum (typically 1 Pa
pressure) is recommended.
ISO 14574:2025(en)
5.4 Set-up for heating
The set-up for heating shall be constructed in such a way that:
— the test coupon maximal temperature will never exceed the desired test temperature of more than 5 °C,
— the gauge length is actually included in the controlled temperature zone.
NOTE 1 When tests are performed in vacuum or inert gas atmospheres, this maximal temperature gradient of 50 °C
in the controlled temperature zone is considered to be low enough to avoid large discrepancy of material behaviour in
the gauge length and then to bias the material properties determination.
NOTE 2 This value of 50 °C is a maximum value of the temperature gradient of the controlled temperature zone
especially for very high temperature test in cold grip configuration. If tests are performed at lower temperature,
temperature gradient lower than 50 °C can be easily achieved.
If the tests are performed under oxidative environment, for CMC materials which are sensitive to oxidative
degradation, the test duration and the controlled temperature zone thermal gradient parameters are to be
set at the lowest values as possible in order to limit the impact on the material properties of the oxidative
degradation. For instance, for material such as CMC including a carbon interphase which are sensitive to
chemical degradation it is recommended to not exceed ±5 °C below 500 °C for the temperature gradient
within the controlled temperature zone.
NOTE 3 An example of calibration method of test temperature and temperature gradient determination is described
in the Annex B.
5.5 Strain measurement
5.5.1 General
For continuous measurement of the longitudinal deformation as a function of the applied force at high
temperature, either suitable contacting or non-contacting extensometer may be used. Measurement of
longitudinal deformation over a length as long as possible within the controlled-temperature zone of the
test specimen is recommended.
5.5.2 Strain gauges
Strain gauges are used for the verification of the alignment on the test specimen at room temperature. They
are not recommended to determine longitudinal deformation during testing at high temperature.
5.5.3 Extensometer
5.5.3.1 General
The extensometer shall be capable of continuously recording the longitudinal deformation at test
temperature. The use of an extensometer with the greatest gauge length is preferable.
Extensometers shall meet the requirements of class 1 or less (class 0,5) in accordance with ISO 9513. Types
of commonly used extensometers are described in 5.5.3.2 and 5.5.3.3.
5.5.3.2 Mechanical extensometer
For a mechanical extensometer, the gauge length shall be the initial longitudinal distance between the two
locations where the extensometer rods contact the t
...