IEC 61788-6:2008

IEC 61788-6
Edition 2.0 2008-01
INTERNATIONAL
STANDARD
Superconductivity –
Part 6: Mechanical properties measurement – Room temperature tensile test of
Cu/Nb-Ti composite superconductors

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC 61788-6
Edition 2.0 2008-01
INTERNATIONAL
STANDARD
Superconductivity –
Part 6: Mechanical properties measurement – Room temperature tensile test of
Cu/Nb-Ti composite superconductors

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
S
ICS 29.050; 77.040.10 ISBN 2-8318-9529-4

– 2 – 61788-6 © IEC:2008(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative references .6
3 Terms and definitions .6
4 Principle .7
5 Apparatus.7
5.1 Conformity.7
5.2 Testing machine .7
5.3 Extensometer .8
6 Specimen preparation.8
6.1 Straightening the specimen .8
6.2 Length of specimen .8
6.3 Removing insulation .8
6.4 Determination of cross-sectional area (S ) .8
o
7 Testing conditions .8
7.1 Specimen gripping.8
7.2 Pre-loading and setting of extensometer .8
7.3 Testing speed.8
7.4 Test.9
8 Calculation of results .9
8.1 Tensile strength (R ) .9
m
8.2 0,2 % proof strength (R and R ) .9
p0,2A p0,2B
8.3 Modulus of elasticity (E and E ) .9
o a
9 Uncertainty.10
10 Test report.10
10.1 Specimen .10
10.2 Results.10
10.3 Test conditions.11

Annex A (informative) Additional information relating to Clauses 1 to 10 .13
Annex B (informative) Uncertainty considerations .18

Bibliography.21

Figure 1 – Stress-strain curve and definition of modulus of elasticity and 0,2 % proof
strengths .12
Figure A.1 – An example of the light extensometer, where R1 and R3 indicate the
corner radius .16
Figure A.2 – An example of the extensometer provided with balance weight and
vertical specimen axis.17

61788-6 © IEC:2008(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
SUPERCONDUCTIVITY –
Part 6: Mechanical properties measurement –
Room temperature tensile test of Cu/Nb-Ti
composite superconductors
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61788-6 has been prepared by IEC technical committee 90:
Superconductivity.
This second edition cancels and replaces the first edition published in 2000. It constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– the minimum distance between grips was changed from 100 mm to 60 mm;
– accuracy and precision statement were converted to uncertainty statements.

– 4 – 61788-6 © IEC:2008(E)
The text of this standard is based on the following documents:
FDIS Report on voting
90/207/FDIS 90/209/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61788 series, published under the general title Superconductivity,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this standard may be issued at a later date.

61788-6 © IEC:2008(E) – 5 –
INTRODUCTION
The Cu/Nb-Ti superconductive composite wires currently in use are multifilamentary
composite material with a matrix that functions as a stabilizer and supporter, in which ultrafine
superconductor filaments are embedded. A Nb-40~55 mass % Ti alloy is used as the
superconductive material, while oxygen-free copper and aluminium of high purity are
employed as the matrix material. Commercial composite superconductors have a high current
density and a small cross-sectional area. The major application of the composite
superconductors is to build superconducting magnets. While the magnet is being
manufactured, complicated stresses are applied to its windings and, while it is being
energized, a large electromagnetic force is applied to the superconducting wires because of
its high current density. It is therefore indispensable to determine the mechanical properties of
the superconductive wires, of which the windings are made.

– 6 – 61788-6 © IEC:2008(E)
SUPERCONDUCTIVITY –
Part 6: Mechanical properties measurement –
Room temperature tensile test of Cu/Nb-Ti
composite superconductors
1 Scope
This part of IEC 61788 covers a test method detailing the tensile test procedures to be carried
out on Cu/Nb-Ti superconductive composite wires at room temperature.
This test is used to measure modulus of elasticity, 0,2 % proof strength of the composite due
to yielding of the copper component, and tensile strength.
The value for percentage elongation after fracture and the second type of 0,2 % proof
strength due to yielding of the Nb-Ti component serves only as a reference (see Clauses A.1
and A.2).
The sample covered by this test procedure has a round or rectangular cross-section with an
2 2
area of 0,15 mm to 2 mm and a copper to superconductor volume ratio of 1,0 to 8,0 and
without the insulating coating.
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.
IEC 60050-815, International Electrotechnical Vocabulary (IEV) – Part 815: Superconductivity
ISO 376, Metallic materials – Calibration of force-proving instruments used for the verification
of u
...