IEC 61788-6:2000

INTERNATIONAL IEC
STANDARD
61788-6
First edition
2000-12
Superconductivity –
Part 6:
Mechanical properties measurement –
Room temperature tensile test of Cu/Nb-Ti
composite superconductors
Supraconductivité –
Partie 6:
Mesure des propriétés mécaniques –
Test de tension à température ambiante
des composites supraconducteurs de Cu/Nb-Ti

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INTERNATIONAL IEC
STANDARD
61788-6
First edition
2000-12
Superconductivity –
Part 6:
Mechanical properties measurement –
Room temperature tensile test of Cu/Nb-Ti
composite superconductors
Supraconductivité –
Partie 6:
Mesure des propriétés mécaniques –
Test de tension à température ambiante
des composites supraconducteurs de Cu/Nb-Ti

 IEC 2000  Copyright - all rights reserved
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– 2 – 61788-6 © IEC:2000(E)
CONTENTS
Page
FOREWORD . 3

INTRODUCTION .4

Clause
1 Scope . 5

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

Annex A (informative) Additional information relating to clauses 1 to 10 . 12
Bibliography . 17
Figure 1 – Stress-strain curve and definition of modulus of elasticity and 0,2 %
proof strengths . 11
Figure A.1 – An example of the light extensometer, where R1 and R3 indicate
the corner radius . 15
Figure A.2 – An example of the extensometer provided with balance weight and
vertical specimen axis .16

61788-6 © IEC:2000(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
SUPERCONDUCTIVITY –
Part 6: Mechanical properties measurement –

Room temperature tensile test of Cu/Nb-Ti composite superconductors

FOREWORD
1) The IEC(International Electrotechnical Commission) is a world-wide organization for standardization comprising
all national electrotechnical committee ( IEC National Committees). The object of the 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, the IEC publishes International Standards. 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 organization liaising with
the IEC also participate in this preparation. The 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 the IEC on technical matters, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested National Committee.
3) The documents produced have the form of recommendations for international use and are published in the
form of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standards and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provided no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The 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.
The text of this standard is based on the following documents:
FDIS Report on voting
90/82/FDIS 90/88/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 3.
Annex A is for information only.
The committee has decided that the contents of this publication will remain unchanged until
2005. 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.

– 4 – 61788-6 © IEC:2000(E)
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. An Nb-40~55 mass% Ti alloy is used as the

superconductive material, while oxygen free copper and aluminum 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.
61788-6 © IEC:2000(E) – 5 –
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 shall serve only as a reference (see clauses A.1 and
A.2).
The sample covered by this test procedure should have a round or rectangular cross-section
2 2
with an area of 0,15 mm to 2 mm and a copper to superconductor volume ratio of 1,0 to 8,0
without the insulating coating.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 61788. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of IEC 61788 are encouraged to investigate the possibility of applying the
most recent edition of the normative document indicated below. For undated references, the
latest edition of the normative document referred to applies. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60050-815:2000, International Electrotechnical Vocabulary (IEV) – Part 815: Super-
conductivity
ISO 6892:1998, Metallic materials – Tensile testing at ambient temperature

ISO 376:1999, Metallic materials – Calibration of force-proving instruments used for the
verification of uniaxial testing machines
ISO 7500-1:1999, Metallic materials – Verification of static uniaxial testing machines – Part 1:
Tension/compression testing machines – Verification and calibration of the force-measuring
system
ISO 9513:1999, Metallic materials – Calibration of extensometers used in uniaxial testing

– 6 – 61788-6 © IEC:2000(E)
3 Terminology
For the purposes of this part of IEC 61788, the definitions given in IEC 60050-815 and

ISO 6892, as well as the following, apply.

3.1
tensile stress
tensile force divided by the original cross-sectional area at any moment during the test

3.2
2)
tensile strength (R )
m
tensile stress corresponding to the maximum testing force
3.3
extensometer gauge length
length of the parallel portion of the test piece used for the measurement of elongation by
means of an extensometer
3.4
distance between grips (L )
g
length between grips that hold a test specimen in position before the test is started
3.5
3)
0,2 % proof strength (R ) (see figure 1)
p0,2
stress value where the cop
...