CEN/TS 15658:2007

SLOVENSKI STANDARD
01-december-2007
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Advanced technical ceramics - Mechanical properties of ceramic fibres at high
temperature under non-reactive environment - Determination of creep behaviour by the
hot end method
Hochleistungskeramik - Mechanische Eigenschaften von Keramikfasern bei hohen
Temperaturen in einer reaktionsfreien Umgebung - Bestimmung des Kriechverhaltens im
Heißverbindungsverfahren
Céramiques techniques avancées - Propriétés mécaniques des fibres céramiques a
haute température sous environnement non réactif - Détermination du comportement au
fluage par la méthode des mors chauds
Ta slovenski standard je istoveten z: CEN/TS 15658:2007
ICS:
81.060.30 Sodobna keramika Advanced ceramics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN/TS 15658
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
September 2007
ICS 81.060.30
English Version
Advanced technical ceramics - Mechanical properties of ceramic
fibres at high temperature under non-reactive environment -
Determination of creep behaviour by the hot end method
Céramiques techniques avancées - Propriétés mécaniques Hochleistungskeramik - Mechanische Eigenschaften von
des fibres céramiques à haute température sous Keramikfasern bei hohen Temperaturen in einer
environnement non réactif - Détermination du reaktionsfreien Umgebung - Bestimmung des
comportement au fluage par la méthode des mors chauds Kriechverhaltens im Heißverbindungsverfahren
This Technical Specification (CEN/TS) was approved by CEN on 20 August 2007 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15658:2007: E
worldwide for CEN national Members.

Contents Page
Foreword.3
1 Scope .4
2 Normative references .4
3 Terms and definitions .4
4 Principle.7
5 Significance and use .7
6 Apparatus .7
6.1 Test installations.7
6.2 Load train.7
6.3 Adhesive .7
6.4 Test chamber.8
6.5 Set-up for heating .8
6.6 Temperature measurement.8
6.7 Control of deformation.8
6.8 Data recording system .8
7 Test specimens.8
7.1 General.8
7.2 Test specimen preparation.8
7.3 Number of test specimens.9
8 Test Procedure.9
8.1 Determination of the temperature profile.9
8.2 Test set-up: other considerations.9
8.3 Loading considerations .10
8.4 Testing technique .10
8.5 Measurements.11
8.6 Test validity .11
9 Calculation of results .12
9.1 Creep stress .12
9.2 Creep strain at time t .12
9.3 Drawing of the creep curve.12
9.4 Creep strain at rupture .12
9.5 Creep rupture time.12
9.6 Creep strain rate curve.12
10 Test report .13
Bibliography .14

Foreword
This document (CEN/TS 15658:2007) has been prepared by Technical Committee CEN/TC 184 “Advanced
technical ceramics”, the secretariat of which is held by BSI.
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.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
1 Scope
This Technical Specification specifies the conditions for the determination of the tensile creep deformation and
failure behaviour of single filaments of ceramic fibres at high temperature and under test conditions that
prevent changes to the material as a result of chemical reaction with the test environment.
This Technical Specification applies to continuous ceramic filaments taken from tows, yarns, braids and
knitted structures, that have strains to failure less than or equal to 5 %.
2 Normative references
The following referenced documents are indispensable for the application 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.
EN 1007-3, Advanced technical ceramics — Ceramic composites — Methods of test for reinforcement —
Part 3: Determination of filament diameter and cross-section area
EN 1007-4, Advanced technical ceramics — Ceramic composites — Methods of test for reinforcement —
Part 4: Determination of tensile properties of filaments at ambient temperature
CEN/TR 13233:2007 , Advanced technical ceramics — Notations and symbols
EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
(ISO/IEC 17025:2005)
EN 60584-1, Thermocouples — Part 1: Reference tables (IEC 60584-1:1995)
EN 60584-2, Thermocouples — Part 2: Tolerances (IEC 60584-2:1982 + A1:1989)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in CEN/TR 13233:2007 and the following
apply.
3.1
creep
time-dependent increase of gauge length starting from the time when the constant specified level of force is
reached
3.2
gauge length
L
initial distance between the gripped ends of filament
3.3
test temperature
T
temperature of the filament in the gauge length
3.4
initial cross section area
A
initial cross section area of the filament within the gauge length
3.5
applied tensile force
F
constant force applied to the filament during the test
3.6
applied tensile stress
σσσσ
applied tensile force divided by the initial cross sectional area
3.7
longitudinal deformation
∆∆∆∆L
change of the gauge length L caused by creep
3.8
creep rupture time
t
cr,m
time elapsed from the moment when loading is completed until the moment of rupture
3.9
creep strain rate
&
ε
cr(T)
change in creep strain per unit time at time t at the temperature T
3.10 Creep types
3.10.1
primary creep
part of the creep strain versus time curve which presents a decreasing creep strain rate (see Figure 1a and
Figure1b)
3.10.2
secondary creep
part of the creep strain versus time curve which presents a constant creep strain rate (see Figure 1a and
Figure 1b)
3.10.3
tertiary creep
part of the creep strain versus time curve which presents an increasing creep strain rate (see Figure 1a and
Figure 1b)
Figure 1a) — Creep strain versus time

Figure 1b) — Creep strain rate versus time
Key
&
1 creep strain ε 6 creep strain rate ε (creep strain with time)
cr cr
7 time
2 time t
3 primary creep 8 primary creep
4 secondary creep 9 secondary creep
5 tertiary creep 10 tertiary creep
Figure 1 — Creep strain and creep strain rate versus time curve
4 Principle
A ceramic filament is heated to the test temperature and loaded in tension until a specified level of force. This
force is maintained at a constant level for a specified time or until rupture. The variation in the ceramic filament
length is recorded in relation to time.
The filament is heated over its total length. The temperature is uniform over the gauge length. However
subjecting the whole length of a filament to temperatures well above 1 000 °C may make it difficult to fix the
ends of the test specimen into appropriate temperature proof extensions. However experimental solutions
based on electric heating of fibre allow this difficulty to be alleviated at temperatures above 1 000 °C.
5 Significance and use
Creep tests allow the determination of data that characterize the deformation rate of materials under constant
load at high temperatures. These are useful for the design of industrial parts with close control of tolerances
for high temperature applications.
6 Apparatus
6.1 Test installations
6.1.1 General
Two different types of installation can be used, as described in 6.1.2 and 6.1.3.
6.1.2 Test machine
The machine shall be equipped with a system for measuring the force applied to the test specimen and a
-3
system for monitoring the applied load. The machine shall have a load cell with a resolution of 10 N for the
applied force. This shall prevail during actual test conditions (pressure, temperature).
-3
Care shall be taken to ensure that the force applied to the filament remains constant to within 10 N, even
when the material properties change and the environmental conditions (temperature, pressure) fluctuate.
6.1.3 Creep testing rig
When a creep testing rig is
...