SIST EN 1892:2005

SLOVENSKI STANDARD
SIST EN 1892:2005
01-september-2005
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SIST ENV 1892:2000
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Advanced technical ceramics - Mechanical properties of ceramic composites at high
temperature under inert atmosphere - Determination of tensile properties
Hochleistungskeramik - Mechanische Eigenschaften von keramischen
Verbundwerkstoffen bei hoher Temperatur in inerter Atmosphäre - Bestimmung der
Eigenschaften unter Zug
Céramiques techniques avancées - Propriétés mécaniques des céramiques composites
a haute température sous atmosphere neutre - Détermination des caractéristiques en
traction
Ta slovenski standard je istoveten z: EN 1892:2005
ICS:
81.060.30 Sodobna keramika Advanced ceramics
SIST EN 1892:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 1892:2005

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SIST EN 1892:2005



EUROPEAN STANDARD
EN 1892

NORME EUROPÉENNE

EUROPÄISCHE NORM
April 2005
ICS 81.060.30 Supersedes ENV 1892:1996
English version
Advanced technical ceramics - Mechanical properties of ceramic
composites at high temperature under inert atmosphere -
Determination of tensile properties
Céramiques techniques avancées - Propriétés mécaniques Hochleistungskeramik - Mechanische Eigenschaften von
des céramiques composites à haute température sous keramischen Verbundwerkstoffen bei hoher Temperatur in
atmosphère neutre - Détermination des caractéristiques en inerter Atmosphäre - Bestimmung der Eigenschaften unter
traction Zug
This European Standard was approved by CEN on 15 March 2005.

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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.

CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1892:2005: E
worldwide for CEN national Members.

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SIST EN 1892:2005
EN 1892:2005 (E)
Contents
Page
Foreword.3
1 Scope .4
2 Normative references .4
3 Terms, definitions and symbols.4
4 Principle.6
5 Apparatus .6
6 Test specimens.8
7 Test specimen preparation.15
8 Test procedures.15
9 Calculation of results .17
10 Test report .19
Annex A (informative) Test specimen for use with optical extensometry.20
Bibliography .21

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SIST EN 1892:2005
EN 1892:2005 (E)
Foreword
This document (EN 1892:2005) has been prepared by Technical Committee CEN/TC 184 “Advanced
technical ceramics”, the secretariat of which is held by BSI.
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 October 2005, and conflicting national standards shall be withdrawn at
the latest by October 2005.
This document supersedes ENV 1892:1996.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
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SIST EN 1892:2005
EN 1892:2005 (E)
1 Scope
This document specifies the conditions for determination of tensile properties of ceramic matrix composite
materials with continuous fibre reinforcement for temperatures up to 2 000 °C under vacuum or a gas
atmosphere which is inert to the material under test.
NOTE The use of these environments is aimed at avoiding changes of the material to be tested due to chemical
reaction with its environment during the test.
This document applies to all ceramic matrix composites with a continuous fibre reinforcement, unidirectional
(1D), bidirectional (2D), and tridirectional (xD, with 2 < x ≤ 3), loaded along one principal axis of reinforcement.
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 10002-4; Metallic materials - Tensile test - Part 4: Verification of extensometers used in uniaxial testing
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)
EN ISO 7500-1, Metallic materials — Verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Verification and calibration of the force-measuring system. (ISO
7500-1:2004)
ISO 3611, Micrometer callipers for external measurement
3 Terms, definitions and symbols
For the purposes of this document, the following terms, definitions and symbols apply.
3.1
test temperature, T
temperature of the test piece at the centre of the gauge length
3.2
calibrated length, l
part of the test specimen which has uniform and minimum cross-section area
3.3
gauge length, L
o
initial distance between reference points on the test specimen in the calibrated length
3.4
controlled temperature zone
part of the calibrated length including the gauge length where the temperature is controlled to within 50 °C of
the test temperature
3.5
initial cross-section area, S
o
initial cross-section area of the test specimen within the calibrated length, at test temperature
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SIST EN 1892:2005
EN 1892:2005 (E)
3.6
longitudinal deformation, A
increase in the gauge length between reference points under a tensile force.
3.7
longitudinal deformation under maximum tensile force, A
m
increase in the gauge length between reference points under maximum tensile force
3.8
tensile strain, ∈∈∈∈
relative change in the gauge length defined as the ratio A/L
o
3.9
tensile strain under maximum tensile force, ∈∈∈∈
m
relative change in the gauge length defined as the ratio A/L corresponding to the maximum force
o
3.10
tensile stress, σσσσ
tensile force supported by the test specimen at any time in the test divided by the initial cross-section area
3.11
maximum tensile force, F
m
highest recorded tensile force in a tensile test on the test specimen when tested to failure
3.12
tensile strength, σσσσ
m
ratio of the maximum tensile force to the initial cross-section area
3.13
proportionality ratio or pseudo-elastic modulus EP
slope of the linear section of the stress-strain curve, if any.
NOTE Examination of the stress-strain curves for ceramic matrix composites allows definition of the following cases:
a) material with a linear section in the stress-strain curve;
For ceramic matrix composites that have a mechanical behaviour characterised by a linear section, the
proportionality ratio is defined as:
()σ −σ
2 1
EP()σ ,σ = (1)
1 2
()∈ − ∈
2 1
where
(∈ , σ ) and (∈ , σ ) lie near the lower and the upper limits of the linear section of the stress-strain curve.
1 1 2 2
The proportionality ratio or pseudo-elastic modulus is termed the elastic modulus, E, in the single case where the linearity
starts near the origin.
b) material with no-linear section in the stress-strain curve.
In this case only stress-strain couples can be fixed.
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SIST EN 1892:2005
EN 1892:2005 (E)
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 1 The test duration is limited to reduce creep effects.
NOTE 2 When constant loading rate is used in the non-linear 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.
5 Apparatus
5.1 Test machine
The test machine shall be equipped with a system for measuring the force applied to the test specimen
conforming to grade 1 or better according to EN ISO 7500-1.
This shall apply 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 attachment fixtures shall align the test specimen axis with the applied force direction.
NOTE 1 The alignment should be verified and documented, according to, for example the procedure described in the
HTMTC code of practice [1].
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;
 cooled grips where the grips are outside the hot zone.
NOTE 2 The choice of gripping system will depend on material, on test specimen design and on alignment
requirements.
NOTE 3 The hot grip technique is limited in temperature because of the nature and strength of the materials that can
be used for grips.
NOTE 4 In the cooled 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 gas tight and shall allow proper control of the test specimen environment in the
vicinity of the test specimen during the test.
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SIST EN 1892:2005
EN 1892:2005 (E)
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 extensometry.
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.
5.4 Set-up for heating
The set-up for heating shall be constructed in such a way that the temperature gradient within the gauge
length is less than 20 °C at test temperature.
5.5 Extensometer
The extensometer shall be capable of continuously recording the longitudinal deformation at test temperature
and conforming to class 1 or better, in accordance with EN 10002-4.
NOTE 1 The use of an extensometer with the greatest gauge length is recommended.
The linearity tolerances shall be lower than 0,05 % of the extensometer range used.
Two commonly used types of extensometer are the mechanical extensometer and the electro-optical
extensometer.
Using a mechanical extensometer, the gauge length is the longitudinal distance between the two locations
where the extensometer rods contact the test specimen.
The rods may be exposed to temperatures higher than the test specimen temperature. Temperature and/or
environment induced structural changes in the rod material shall not affect the accuracy of deformation
measurement. The material used for the rods shall be compatible with the test specimen material.
NOTE 2 Care should be taken to correct for changes in calibration of the extensometer that may occur as a result of
operating under conditions different from calibration.
NOTE 3 Rod pressure onto the test specimen should be the minimum necessary to prevent slipping of the
extensometer rods.
In the case of an electro-optical extensometer, electro-optical measurements in transmission require reference
marks on the test specimen. For this purpose rods or flags shall be attached to the surface perpendicularly to
its axis. The gauge length shall be the distance between the two reference marks. The material used for
marks (and adhesive if used) shall be compatible with the test specimen material and the test temperature
and shall not modify the stress field in the specimen.
NOTE 4 The use of integral flags as parts of the test specimen geometry is not recommended because of stress
concentration induced by such features.
5.6 Temperature measurement devices
For temperature measurement, either thermocouples conforming to EN 60584-1 and EN 60584-2 shall be
used, or, where thermocouples not conforming to EN 60584-1 and EN 60584-2 or pyrometers are used,
calibration data shall be annexed to the test report.
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SIST EN 1892:2005
EN 1892:2005 (E)
5.7 Data recording system
A calibrated recorder may be u
...