ISO 4255:2025

Fine ceramics (advanced ceramics, advanced technical ceramics) — Mechanical properties of ceramic composites at high temperature — Determination of axial tensile properties of tubes

This document specifies the conditions for determination of the axial tensile properties of ceramic matrix composite (CMC) tubes with continuous fibre-reinforcement at elevated temperature in air, vacuum and inert gas atmospheres. The applicability of this document is specific to tubular geometries because fibre architecture and specimen geometry factors in composite tubes are distinctly different from those in flat specimens. This document provides information on the axial tensile properties and stress-strain response in temperature, such as axial tensile strength, axial tensile strain at failure and elastic constants. The information can be used for material development, control of manufacturing (quality insurance), material comparison, characterization, reliability and design data generation for tubular components. This document addresses, but is not restricted to, various suggested test piece fabrication methods. This document is primarily applicable to ceramic matrix composite tubes with a continuous fibrous-reinforcement: unidirectional (1D, filament winding and tape lay-up), bi-directional (2D, braid and weave) and multi-directional (xD, with x > 2), tested along the tube axis.

Céramiques techniques — Propriétés mécaniques des composites céramiques à haute température — Détermination des propriétés en traction axiale de tubes

General Information

• Status: Published
• Publication Date: 07-Jul-2025
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: ISO/TC 206 - Fine ceramics
• Drafting Committee: ISO/TC 206 - Fine ceramics
• Current Stage: 6060 - International Standard published
• Start Date: 08-Jul-2025
• Due Date: 08-Dec-2025
• Completion Date: 08-Jul-2025

Relations

• Consolidates: ISO 230-10:2022 - Test code for machine tools — Part 10: Determination of the measuring performance of probing systems of numerically controlled machine tools
• Effective Date: 11-Nov-2023

Standards Content (Sample)

International
Standard
ISO 4255
First edition
Fine ceramics (advanced ceramics,
2025-07
advanced technical ceramics) —
Mechanical properties of ceramic
composites at high temperature
— Determination of axial tensile
properties of tubes
Céramiques techniques — Propriétés mécaniques des composites
céramiques à haute température — Détermination des propriétés
en traction axiale de tubes
Reference number
© 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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 4
5 Apparatus . 5
5.1 Testing machine . .5
5.2 Gripping system . .5
5.2.1 Test specimen gripping.5
5.2.2 Location and temperature of grips .5
5.2.3 Load train couplers .6
5.3 Test chamber and heating set-up .6
5.4 Heating apparatus .7
5.5 Strain measurement .7
5.5.1 General .7
5.5.2 Extensometers.7
5.5.3 Digital image correlation .8
5.6 Temperature measurement devices .8
5.7 Data recording system .8
5.8 Dimension-measuring devices .9
6 Tubular test specimen . 9
6.1 Specimen specifications .9
6.1.1 General .9
6.1.2 Dimension .9
6.1.3 Geometry commonly used .9
6.1.4 Tolerances and variability .11
6.2 Specimen preparation .11
6.2.1 General .11
6.2.2 As-fabricated .11
6.2.3 Application-matched machining .11
6.2.4 Customary practices . 12
6.2.5 Standard procedure . . . 12
6.3 End collars and alignment issue . 12
6.4 Test count and test specimens sampling .14
7 Test procedure . 14
7.1 Temperature considerations .14
7.1.1 General .14
7.1.2 Controlled temperature zone .14
7.1.3 Temperature measurement .14
7.2 Test set-up: other considerations .14
7.3 Testing technique . 15
7.3.1 Measurement of test specimen dimensions . 15
7.3.2 Instrumentation of the test specimen . 15
7.3.3 Specimen mounting . 15
7.3.4 Setting-up of strain measurement means . 15
7.3.5 Setting-up of inert atmosphere .16
7.3.6 Heating of test specimen and temperature control .16
7.3.7 Measurements .16
7.3.8 Post-test analyses .17
7.4 Test validity .17
8 Calculation of results . 17
8.1 Test specimen origin .17

iii
8.2 Engineering axial tensile stress and strain .18
8.3 Tensile strength .18
8.4 Strain at maximum tensile force .19
8.5 Tensile modulus .19
8.5.1 Calculation of tensile modulus .19
8.5.2 Calculation of tensile elastic modulus with linear region . 20
8.5.3 Stress for materials with non-linear stress-strain curve . 20
8.6 Poisson’s ratio (optional) . 20
8.7 Statistics . 20
9 Test report .21
9.1 General .21
9.2 Testing information . .21
9.3 Test specimen and material .21
9.3.1 Tubular test specimen drawing or reference .21
9.3.2 Description of the test material .21
9.4 Equipment and test parameters .21
9.4.1 Testing machine type and configuration .
...

International
Standard
ISO 4255
First edition
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Mechanical properties of ceramic
composites at high temperature
— Determination of axial tensile
properties of tubes
PROOF/ÉPREUVE
Reference number
© 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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 4
5 Apparatus . 5
5.1 Testing machine . .5
5.2 Gripping system . .5
5.2.1 Test specimen gripping.5
5.2.2 Location and temperature of grips .5
5.2.3 Load train couplers .6
5.3 Test chamber and heating set-up .6
5.4 Heating apparatus .7
5.5 Strain measurement .7
5.5.1 General .7
5.5.2 Extensometers.7
5.5.3 Digital image correlation .8
5.6 Temperature measurement devices .8
5.7 Data recording system .8
5.8 Dimension-measuring devices .9
6 Tubular test specimen . 9
6.1 Specimen specifications .9
6.1.1 General .9
6.1.2 Dimension .9
6.1.3 Geometry commonly used .9
6.1.4 Tolerances and variability .11
6.2 Specimen preparation .11
6.2.1 General .11
6.2.2 As-fabricated .11
6.2.3 Application-matched machining .11
6.2.4 Customary practices . 12
6.2.5 Standard procedure . . . 12
6.3 End collars and alignment issue . 12
6.4 Test count and test specimens sampling .14
7 Test procedure . 14
7.1 Temperature considerations .14
7.1.1 General .14
7.1.2 Controlled temperature zone .14
7.1.3 Temperature measurement . 15
7.2 Test set-up: other considerations . 15
7.3 Testing technique . 15
7.3.1 Measurement of test specimen dimensions . 15
7.3.2 Instrumentation of the test specimen .16
7.3.3 Specimen mounting .16
7.3.4 Setting-up of strain measurement means .16
7.3.5 Setting-up of inert atmosphere .16
7.3.6 Heating of test specimen and temperature control .16
7.3.7 Measurements .17
7.3.8 Post-test analyses .17
7.4 Test validity .17
8 Calculation of results .18
8.1 Test specimen origin .18
PROOF/ÉPREUVE
iii
8.2 Engineering axial tensile stress and strain .18
8.3 Tensile strength .19
8.4 Strain at maximum tensile force . 20
8.5 Tensile modulus . 20
8.5.1 Calculation of tensile modulus . 20
8.5.2 Calculation of tensile elastic modulus with linear region . 20
8.5.3 Stress for materials with non-linear stress-strain curve .21
8.6 Poisson’s ratio (optional) .21
8.7 Statistics .21
9 Test report .22
9.1 General . 22
9.2 Testing information . . 22
9.3 Test specimen and material . 22
9.3.1 Tubular test specimen drawing or reference . 22
9.3.2 Description of the test material . 22
9.4 Equipment and test parameters . 22
9.4.1 Testing machine type and configuration . 22
9.4.2 Temperature and force measurement description .
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ISO/DISPRF 4255:2024(en)
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ISO /TC 206/WG 4
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Secretariat: JISC
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Date: 2024-08-192025-05-21
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Fine ceramics (advanced ceramics, advanced technical
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temperature — Determination of axial tensile properties of tubes
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Céramiques techniques (céramiques avancées, céramiques techniques avancées) — Propriétés mécaniques
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des céramiques composites à haute température — Détermination des propriétés en traction axiale de
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PROOF
ISO/PRF 4255:2025(en)
Formatted: Font: Bold
Formatted: HeaderCentered
Formatted: Default Paragraph Font
Formatted: Adjust space between Latin and Asian text,
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
Adjust space between Asian text and numbers
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
Formatted: English (United Kingdom)
Formatted: English (United Kingdom)
Fax: [phone]
EmailE-mail: [e-mail]
Formatted: zzCopyright address, Adjust space between
Website: www.iso.orgwww.iso.org
Latin and Asian text, Adjust space between Asian text
and numbers
Published in Switzerland
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ii
ISO/DISPRF 4255:20242025(en) Formatted: Font: 11 pt
Formatted: Font: 11 pt
Formatted: Font: 11 pt
Contents
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Foreword . Error! Bookmark not defined.
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1 Scope . Error! Bookmark not defined.
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2 Normative references . Error! Bookmark not defined.
3 Terms and definitions . Error! Bookmark not defined.
4 Principle. Error! Bookmark not defined.
5 Apparatus . Error! Bookmark not defined.
5.1 Testing machine . Error! Bookmark not defined.
5.2 Gripping system . Error! Bookmark not defined.
5.3 Test chamber and heating set-up . Error! Bookmark not defined.
5.4 Heating apparatus . Error! Bookmark not defined.
5.5 Strain measurement . Error! Bookmark not defined.
5.6 Temperature measurement devices . Error! Bookmark not defined.
5.7 Data recording system . Error! Bookmark not defined.
5.8 Dimension-measuring devices . Error! Bookmark not defined.
6 Tubular test specimen . Error! Bookmark not defined.
6.1 Specimen specifications . Error! Bookmark not defined.
6.2 Specimen preparation . Error! Bookmark not defined.
6.3 End collars and alignment issue . Error! Bookmark not defined.
6.4 Test count and test specimens sampling . Error! Bookmark not defined.
7 Test procedure . Error! Bookmark not defined.
7.1 Temperature considerations . Error! Bookmark not defined.
7.2 Test set-up: other considerations . Error! Bookmark not defined.
7.3 Testing technique . Error! Bookmark not defined.
7.4 Test validity . Error! Bookmark not defined.
8 Calculation of results . Error! Bookmark not defined.
8.1 Test specimen origin . Error! Bookmark not defined.
8.2 Engineering axial tensile stress and strain . Error! Bookmark not defined.
8.3 Tensile strength . Error! Bookmark not defined.
8.4 Strain at maximum tensile force . Error! Bookmark not defined.
8.5 Tensile modulus . Error! Bookmark not defined.
8.6 Poisson’s ratio (optional) . Error! Bookmark not defined.
8.7 Statistics . Error! Bookmark not defined.
9 Test report . Error! Bookmark not defined.
9.1 General . Error! Bookmark not defined.
9.2 Testing information . Error! Bookmark not defined.
9.3 Test specimen and material . Error! Bookmark not defined.
9.4 Equipment and test parameters . Error! Bookmark not defined.
9.5 Test results . Error! Bookmark not defined.
10 Uncertainties . Error! Bookmark not defined.
(informative) Illustration of tensile modulus. Error! Bookmark not defined. Formatted: Font: 10 pt
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Foreword . 4
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1 Scope . 0
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iii
ISO/PRF 4255:2025(en)
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2 Normative references . 0
3 Terms and definitions . 1
Figure 1 — Cylindrical coordinate system used for the CMC tubes . 3
4 Principle . 3
5 Apparatus . 4
5.1 Testing machine . 4
5.2 Gripping system . 4
5.2.1 Test specimen gripping . 4
5.2.2 Location and temperature of grips . 4
Figure 2 — Example of “cold grip” configuration for the determination of the axial properties of
CMC tubes at high temperature . 5
5.2.3 Load train couplers . 5
5.3 Test chamber and heating set-up . 5
5.4 Heating apparatus . 5
5.5 Strain measurement . 5
5.5.1 General. 5
5.5.2 Extensometers . 6
5.5.3 Digital image correlation . 6
5.6 Temperature measurement devices . 7
5.7 Data recording system . 7
5.8 Dimension-measuring devices . 7
6 Tubular test specimen . 7
6.1 Specimen specifications . 7
6.1.1 General. 7
6.1.2 Dimension . 8
6.1.3 Geometry commonly used . 8
Figure 3 — “Generic” straight-side tube test specimen . 8
Table 1 — Dimensional requirements for straight-side tube test specimen type . 8
Figure 4 — “Generic” contoured gauge tube test specimen . 8
Table 2 — Dimensional requirements for contoured gauge tube test specimen type . 8
6.1.4 Tolerances and variability . 9
6.2 Specimen preparation . 9
6.2.1 General. 9
6.2.2 As-fabricated .
...