DE3905805C2 - A method of making a wire-form superconducting composite article - Google Patents

Description

The invention relates to a method for producing a wire-shaped superconducting composite article. This composite article contains Nb₃Al as superconducting compound and includes, but not limited to, excellent Superconducting characteristics or characteristics in high magnetic fields and AC magnetic fields.

Superconducting wire-shaped composite articles for high magnetic fields, in which Nb₃Sn and V₃Ga as a linear superconducting Material used, have been used previously. also is used as a superconducting material for alternating current Superconducting multifilamentary Nb-Ti wire in practice used. For example, it refers to "Superconductor Materials Science, Metallurgy, Fabrication and Application "(NATO ADVANCED STUDY INSTITUTES SERIES, Series B; Physics), edited by Simon Fonder and Brian B. Schwartz, Chapter 2; "Practical Superconducting Materials", Pages 63-67, noted.

The composite articles, the Nb₃Sn and V₃Ga as linear superconducting Matrial are by a method made pulling a composite or Composites, the or a copper alloy (Cu-Sn alloy or Cu-Ga alloy) and Nb or V is composed, while an intermediate annealing in vacuum at temperatures is carried out in the range of 500 to 600 ° C, these Is repeated several times, and  after that, the product becomes a heat treatment for a diffusion reaction exposed.

During drawing, oxygen-free copper stabilizes compounded in the linear material, but that makes the insertion of tantalum foil, niobium foil etc. into spaces among the linear materials as a diffusion barrier necessary to initiate a diffusion reaction between the to avoid oxygen-free copper and the copper alloy.

Therefore, the manufacturing method of previously known wire-shaped composite articles, the Nb₃Sn and V₃Ga contain, as described above, very arduous fabrication steps, and a reduction in production costs These composite objects are difficult. also is the upper critical magnetic field strength the superconducting material obtained thereby, containing Nb₃Sn and V₃Ga, only about 20 T, and the Ability of these composite objects to high magnetic fields deliver is limited.

On the other hand, a first practical ultrafine multifilament was Composite wire, the extremely low AC losses showed, by the use of Nb-Ti alloy made available. However, the critical temperature is this Nb-Ti alloy 9 K, and when in liquid Helium (4.2 K) is the temperature margin only 4.8 K. Wired composite objects of such a small Temperature latitudes are not very beneficial for use as superconducting magnets for alternating current, because in the magnet is always a constant amount during operation heat generation occurs and because at temperatures, which are adjacent to the critical temperature or these exceed the magnetic performance deteriorates  becomes or stagnates.

On the other hand, it is known that the Nb₃Al compound has critical temperatures (T _c ) which are in the range of 15 to 19 K and an upper critical magnetic field of 30 T, the aforementioned temperature margin of at least 10 K and superior superconducting characteristics to either of the aforementioned Nb₃Sn-V₃Ga composite articles or to the aforesaid Nb-Ti alloy ultrafine multi-filamentary wire.

However, the Nb₃Al compound has been a serious one so far Disadvantage in terms of their practical use insofar, when it was very difficult to make a wire-shaped material, in particular a homogeneous wire-shaped material with ultrafine thickness. That is, it was about results from laboratory-scale experiments of compression a powdery mixture of Nb and Al to one Solids, solid-state drawing and heat treatment the same reported that the obtained, relatively short composite wire-shaped article excellent superconducting characteristics or -kenndaten, as described above, showed. However, it is extremely difficult, a long, thread-like Product, in particular a long, ultrafine and homogeneous form filamentary product from this Nb₃Al compound, and because of this, this connection has not been made yet exploited commercially.

The above facts are the following refer to:

• (i) "Advances in Cryogenic Engineering", Vol. 34, "Materials," pages 461-468;  
• (ii) "IEEE Transactions on Magnetics", Vol. Mag-21, No. 2, pp. 756-759 (1985);
• (iii) "IEEE Transactions on Magnetics", Vol. Mag-23, No. 2, pp. 653-656 (1987).

One of the reasons why a wire made of Nb₃Al compound, produced by the Pulverfahren in laboratory scale test has been, as mentioned above, despite its excellent Superconducting properties not commercialized lies in the extreme difficulties of preventing oxidation of Nb and Al powders known as Serving starting material, and controlling their particle sizes.

On the other hand, the production of wires was also from Nb₃Al compound through the steps of forming Filaments or thin films of Nb and pure Al, the Compounding the same, the cold drawing of the composite material and the heat treatment of the same tries. Because of the lower hardness, which is the pure aluminum compared to the Hardness of Nb, however, aluminum shows an abnormal deformation while pulling, which sometimes causes a break of the wire is effected. As a result, one can fine and homogeneous filamentous product not obtained As a result, the process has not been commercialized.

Furthermore, from DE-OS 22 00 769 a method for manufacturing a wire-shaped superconducting composite article known, comprising the following method steps:

• (1) collecting a number of strand-like composite elements, which
  • (a) either an aluminum core and a sheath of niobium directly surrounding it, or
  • (b) a niobium core and an aluminum sheath directly surrounding it
• and each have a further, outer sheath possess, made of a stretchable material good Heat and electricity conductor features, such as for example, made of copper;
• (2) insert this number of composite elements into one Tube made of the same material as the outer one Sheathing of the individual composite elements, for example, in a copper pipe;
• (3) Pull the pipe together with the composite elements to a composite article; and
• (4) heat-treating the obtained composite article to form the superconducting compound Nb₃Al.

Problematic in this method according to DE-OS 22 00 769 in particular, that by, for example, copper existing and for the stabilization of the composite article considered as indispensable outer sheath of the individual Composite elements the final achievable packing density the resulting in the heat treatment superconducting Strands of Nb₃Al is significantly limited.  

Finally, from DE-OS 21 65 130 a method for Production of a wire-shaped superconducting composite article known with an aluminum coating, in which a strand of three or more superconducting wires in a tube high purity aluminum is used and this pipe then in another tube made of an aluminum alloy with a predetermined minimum hardness is used, to thereby form a triple layer structure, which then is pulled to a superconductor unit which is opposite to the Triple layer structure to less than 5% in the surface is reduced, after which a plurality of such superconductor units bundled and twisted or intertwined and the outer surface of the thus formed multiple superconductor with an aluminum alloy layer is surrounded.

In this method according to DE-OS 21 65 130 is indeed a Aluminum alloy in a wire-shaped superconducting composite article however, this aluminum alloy will be used in combination with high-purity aluminum as the wrapping material used for the actual superconducting material, because high purity aluminum in terms of electrical Stabilization of the superconductor brings benefits, during aluminum alloy during mechanical processing and the damping of eddy currents more favorable properties having. The aluminum alloy is according to DE-OS 21 65 130 but not as one of the starting materials for production used the actual superconducting material.

The object of the invention is a process for the preparation a wire-shaped superconducting composite article having Nb₃Al to provide as a superconducting compound, which allows superconductors with extremely fine superconducting Produce filaments.  

This object is achieved according to the invention by a method which has the features of claim 1 or 2.

With this method according to the invention can be industrial to produce useful wire-shaped composite articles whose extremely fine and homogeneous filaments of Nb₃Al excellent Have superconducting characteristics or characteristics.

In particular, those with the inventive method manufactured wire-shaped superconducting composite objects only a few AC losses with excellent mechanical Strength and high resistance to bending stress, and they are for use as materials suitable for AC superconducting devices, for example for superconducting transformers and superconducting Generators.

The method provided by the invention is otherwise a practical and economical procedure for the production of ultrafine superconducting filaments consisting of Nb₃Al composite objects.

Further developments of the method according to the invention and the preferred Use of the wire-shaped Superconducting composite articles are in the subclaims specified.

According to the investigations carried out in the context of the present invention were carried out, it was found that the above stated advantages of the present invention as well as the solution the above object, on which the invention is based, achieved by the method specified in claim 1 or 2 which will allow a long,  wire-shaped composite article, in particular characterized in that a large number of composite filaments at a distance from each other in a continuous Layer consisting of copper, a copper alloy, Niobium, tantalum or vanadium exists, with each one the composite filaments has such a structure that at least a strand of an aluminum alloy or niobium sheathed is and essentially of extremely fine, thread-like Superconducting Nb₃Al compound is made, the one average diameter of about 0.03 microns to about 1 micron.

With the method according to the present invention, as above, a long, wirelike superconducting composite article made in which a large number of filaments made of ultrafine, filamentary Nb₃Al with a middle Diameters of about 0.03 microns to about 1 micron are present, which composite article as a part for superconducting devices serves and excellent superconducting characteristics or characteristics and high industrial value, which also makes these superconducting devices excellent superconducting characteristics and high industrial value Get value. In particular, this wire-shaped Composite article a durability or durability to tensile or tensile stress, at least about three times larger than that of conventional superconducting composite articles, not only that Installation in superconducting facilities facilitates, but the built-in wire-shaped composite article has in an advantageous Also a high mechanical strength.

Furthermore, the method according to the present invention relatively simple, as can be seen from the explanation given later is, and it does not require the use of such parts  like tantalum or niobium foil, which is expensive and easy to handle are cumbersome. As a result, the economic value of the present invention is indeed large.

In the produced according to the invention long, wire-shaped Composite article is a large number of filamentary Nb₃Al compound along its longitudinal direction present. The mean diameter the thread-shaped Nb₃Al compound is in the range from about 0.03 μm to about 1 μm, preferably in the range from about 0.05 μm to about 0.5 μm. The Nb₃Al compound is characterized by their extreme fineness and high homogeneity. With the "diameter" as given here is the diameter of a hypothetical circle of the Area meant by a single strand of filamentary Nb₃Al compound in the cross section of wire-shaped composite article, cut perpendicular to the longitudinal direction of the composite article becomes. Therefore, with the term "mean diameter" the arithmetic mean or the arithmetic mean the diameter of the large number of filamentary Nb₃Al- Compound present in the mentioned cross-section meant.

The configuration of the cross section of the filamentary Nb₃Al- Connection is not critical, which configuration for example circular, elliptical, rectangular or triangular  can be, being a circular or elliptical Configuration is generally preferred.

The above filamentary Nb₃Al compound is covered by an aluminum alloy or niobium. This means that the cross section has an appearance as shown in FIG . 1 (a) or in particular in FIG . Figure 1 (b) illustrates where 1 denotes the Nb₃Al compound, while 2 denotes aluminum alloy or niobium, with 1 and 2 together forming the composite filament.

In such a composite filament contains the aluminum alloy preferably at least one metal selected from the group is selected, which consists of Cu, Mg, Zn, Li and Ag, and more preferably in a content of 15 atomic% of such other metals or other metals (derived from the group selected above). The most preferred aluminum alloy contains of about 0.1 to about 15 atomic%, preferably from about 2 to about 15 atomic%, inter alia, from about 3 to about 10 atomic%, of at least one metal consisting of Mg, Zn, Li and Ag existing group, or it is an aluminum-copper alloy, from about 0.5 to about 3 atomic%, preferably from about 1 to about 2 atomic%, of Cu.

The aluminum alloy or niobium may further contain up to about 4 atomic percent Si and / or Ge. When such an additional component is included or when such additional components are included, the composite article having an improved critical temperature (T _c ) and improved critical current density (J _c ) can be obtained.

In the wire-shaped superconducting composite article produced by the method according to the present invention, a large number of composite filaments having such a structure that at least one strand of the filamentary Nb₃Al compound encased in an aluminum alloy or niobium is in a continuous layer consisting of copper, copper alloy, niobium, tantalum or vanadium, spaced apart. The cross-sections of this composite article can be schematically in particular as shown in FIGS . 2 (a), 2 (b) or 2 (c), wherein 3 and 4 denote the composite elements, while 5 and 6 designate the tube which is there to form a continuous copper, copper alloy, niobium, tantalum or vanadium layer has become.

In the wire-shaped manufactured according to the present invention Superconducting composite article is advantageous a large number of the mentioned composite filaments parallel along the longitudinal direction of the composite article present, and at a distance from each other, preferably without contact with each other at any point, and more preferably in the same distance relationship to one another, especially at equal and uniform intervals from each other.

So that a large number of composite filaments in the invention manufactured wire-shaped composite article is present at a distance from each other, it is necessary that Copper, a copper alloy, niobium, tantalum or vanadium one forms continuous layer. Copper or a copper alloy is preferred as a continuous layer material. As such, copper or such copper alloy can be oxygen-free copper, copper-nickel and copper-manganese  Alloy can be specified, among which oxygen-free Copper and copper-nickel are preferred.

The configuration of the cross section, transverse to the longitudinal direction of the composite filament is not critical, they may be circular, elliptical, rectangular, for example or triangular, where generally the configuration of a circular or elliptical cross-section is preferred.

In the wire-shaped superconducting composite article, the produced by the method according to the present invention is at least about 100,000, preferably about 100,000 to about 100,000,000 strands of composite filaments included, thus ensuring better utility and usability results. Further, it is more practical that the wire-shaped Composite article is manufactured so that it has a average diameter, which is generally from about 0.2 mm is about 5 mm, in particular in the range of about 0.3 mm is about 4 mm.

In the method according to the invention, the aforementioned extremely fine and homogeneous filamentary Nb₃Al compound an aluminum alloy and niobium as the base materials used. This is a composite material, the is composed of an aluminum alloy and niobium, in particular a strand-shaped composite element of the one-core Type in which one of the two components forms the core and the other surrounds the core, in particular shrouded, as used the starting material, which is pulled until the Thickness (diameter if the material is wire-formed) of the strand Aluminum alloy has been reduced to not more than 1 micron and thereafter becomes a heat treatment at high temperatures carried out.  

In the method of the invention described above it by using an aluminum alloy instead the previously known pure aluminum made possible the extremely fine and homogeneous filamentary Nb₃Al compound form and the wire-shaped composite object to obtain a high resistance to elongation or tensile stress has.

As the aluminum alloys, for the inventive Are useful, those are suitable, the one Hardness which is higher than that of pure aluminum is and is relatively close to that of niobium. When such aluminum alloy are those which are preferred Aluminum and at least one metal are assembled, which is selected from the group consisting of Cu, Mg, Zn, Li and Ag exists (it should be noted that everywhere where in the context of the present description and in the Claims of "at least one metal" or "at least a part "in connection with a group the question is, from which this metal or this part or component is selected, always means that off at least one metal or part or Component is selected, but also several metals or parts or components of the in question Group can be selected, in extreme cases all Components of the group can be used simultaneously). In particular, such aluminum alloys are preferred, not more than about 15 atomic% of such another Metal or other metals. As part of the description and the claims mean "at.%" atomic%, d. H. a percentage value of the atomic ratio of each of the metals to the entire metals, which is the alloy put together.  

Particularly advantageous aluminum alloys are those which from about 0.1 to about 15 at.%, preferably about 2 to about 15 at.%, more preferably about 3 to about 10 at.%, containing at least one metal selected from the group is selected, which consists of Mg, Zn, Li and Ag, or those from about 0.5 to about 3 at.%, more preferably from about 1 to about 2 at.%, of Cu.

The aluminum alloy can only one of the aforementioned metals or more than one of these metals. Examples of possible combinations in the alloys Cu-Al, Mg-Al, Zn-Al, Li-Al, Ag-Al, Cu-Mg-Al, Cu-Mg-Li-Al, Cu-Mg-Li-Ag-Al, Mg-Li-Al and Zn-Ag-Al. There is no critical limitation on the combination of elements.

These combinations and the respective amount of addition of each component are chosen to be aluminum alloys the hardness and hardening rate under cold working which approximates the same as those of Nb and within the range for the superconducting characteristics or characteristics of the filamentary Nb₃Al- Compound is not harmful.

It is also possible to pre-compound the aluminum alloy same with niobium a solution treatment, quenching and annealing to increase the hardness of the aluminum alloy to subjugate. By performing such treatments can the amount of other metal or other metals, which is to be added to the aluminum alloy or are diminished.

Below are preferred embodiments of the method according to the invention with reference to the figures the drawing explained in more detail; it shows

Fig . 1 (a) and (b) are cross sections illustrating examples of Nb-Al alloy composite members used in the production method of the present invention; and

Fig . 2 (a), (b) and (c) are cross-sections of a plurality of strand-like composite elements spaced apart in a continuous layer, each consisting of oxygen-free copper, copper-nickel or oxygen-free copper and copper-nickel.

In the figures of the drawing, the reference numerals each following:

1 a matrix of niobium or aluminum alloy 2 Strands of aluminum alloy or niobium 3 and 4 composite elements 5 Tube made of oxygen-free copper 6 Tube made of copper-nickel

As shown in FIG . 1 (a) and (b), first composite members 3 and 4 composed of a matrix 1 of Nb and a strand 2 of aluminum alloy are produced. These materials are cold drawn into a composite filament until the thickness (diameter) of the strand 2 is reduced to not more than 1 μm. Then, the composite members 3 and 4 drawn into a composite filament are heat-treated at high temperatures of, for example, about 700 ° C to about 2300 ° C. This produces the filamentary Nb₃Al superconducting material having a thickness (diameter) which does not exceed about 1 μm, which has excellent high magnetic field properties and AC characteristics.

It should be further to the Fig . 1 (a) and (b) and noted that the composition of Nb and the aluminum alloy can be reversed. That is, the composite members 3 and 4 may be such that 1 is an aluminum alloy matrix and 2 is a niobium strand. However, it is preferred to start from a composite element in which 1 is a niobium matrix and 2 is an aluminum alloy strand.

More specifically, first, as strand 2, one or more aluminum alloy rods having approximately the same degree of hardening rate in processing as that of Nb are inserted into a Nb tube as matrix 1 and pulled together, in particular cold drawing, so that they are stretched into a composite element 3 or 4 in the form of a long round bar.

The cold-drawing rod or wire production can be carried out with a composite basic rod of multi-layer structure obtained by inserting the composite member 3 or 4 into an oxygen-free copper pipe or a copper-nickel pipe 6 or a pipe formed of these two. as shown in Figs . 2 (a), 2 (b) and 2 (c), said pipe material serving as a stabilizing material (a low electrical resistance material necessary for a high capacitance conductor) or as a coupling current. Breaking material (a material of high electrical resistance necessary for an AC conductor). Although, as explained above with FIGS. 5 and 6, a tube made of oxygen-free copper or copper-nickel is designated to simplify the explanation, it should be noted that each of these tubes is also made of copper-manganese alloy, niobium, tantalum or vanadium can be with the same effect.

In addition, as mentioned above, in Figs . 1 (a) and 1 (b) 1 also be a matrix of an aluminum alloy and 2 also a strand of niobium. If, in a composite member composed of an aluminum alloy and niobium in the above manner, the filiform body is formed of niobium and the continuous aluminum alloy layer, then the periphery of the composite member must be coated with niobium, tantalum, vanadium or a mixture thereof and the whole as the composite elements 3 and 4 of FIG . 2 are used. Namely, if such a coating were omitted and the aluminum alloy exposed uncoated, it would come into direct contact with oxygen-free copper, copper-nickel or copper-manganese alloy, which would cause a diffusion reaction of the aluminum and copper during the heat treatment process step described below.

Oxygen-free copper, copper-nickel, copper-manganese alloy, niobium, tantalum or vanadium as a continuous layer of the pipe 5 and 6 in FIG . 2 not only have the rate of cold working similar to that of aluminum alloy and niobium, but also reduce the frictional resistance between the matrix continuous layer and the composite elements during drawing, thus facilitating the processing.

More specifically, several tens to several hundreds of the composite members 3 or 4 composed of a matrix 1 of Nb and a strand 2 of aluminum alloy are bundled and inserted into a tube 5 of oxygen-free copper or a tube 6 of copper-nickel, and this multi-core structured composite material is processed into a composite filament of a long, thread-like shape by drawing, in particular cold drawing. The composite filament obtained as a product is further cut into a plurality of strands of appropriate length, and several tens or hundreds of the strands are bundled and re-inserted into a tube 5 of oxygen-free copper or a tube 6 of copper-nickel and made into a long, processed thread-like shape. In this way, a multi-core structured new composite filament having several thousand to several tens of thousands of strands of aluminum alloy cores is obtained. The resulting novel composite filament is further processed through the process steps described above to finally obtain a wire-form composite article having several hundred thousand to several tens of millions strands of aluminum alloy cores.

One of the remarkable features of the present method is that the wire-shaped composite article as the final product in which the aluminum alloy cores each have a diameter, not greater than about 1 μm, and a homogeneous composition, can be obtained with ease.

When pure aluminum is used in the above drawing processing is used instead of aluminum alloy is the material is too soft to be processed to a diameter to be able to be no larger than 1 micron. If vice versa the aluminum alloy is too hard, the drawing processing becomes difficult.  

In the case where an aluminum alloy is used which is too hard becomes an intermediate annealing at a temperature low enough that they do not have a diffusion reaction caused at the Nb-Al interface, for example at 300 to 400 ° C, and indeed about half the processing.

The resulting composite wire-like article becomes at temperatures between about 700 to about 2300 ° C, preferably about 750 to about 2000 ° C, heat treated to a diffusion reaction between the aluminum alloy and niobium for training effect of filamentary Nb₃Al compound.

According to the investigations carried out in the context of the present invention were carried out, it was found that if the heat treatment of the aforementioned composite article in a higher part of the above temperature range during a very short period of time, wire-shaped Composite objects can be obtained which even more the critical current density in high magnetic Fields surpass.

This high temperature short term heat treatment is during a very short period of time of not more than about 10 Seconds, preferably not longer than about 5 seconds, carried out at temperatures ranging from about 1100 ° C to about 2300 ° C, preferably in the range of about 1400 ° C to about 2000 ° C, lie. As the heat treatment at such high temperatures only for a short time be executed, will be funds for this Purpose suitable, applied. In preferred embodiments For example, the composite wire-wound article may be by means of direct Heating by electric current, by means of induction heating,  by radiation heating or by combination These types of heating are heated, followed by an immediate cooling. Generally, the heat treatment by continuous heating and cooling of the composite article during transport of the wire-shaped composite article be performed. This heat treatment is preferably in an inert gas atmosphere and / or in liquefied Inert gas performed.

When the composite wire-formed article after the above high-temperature short-time heat treatment further a Nachwärmebehandlung at about 600 to about 800 ° C, can its characteristics in high magnetic fields even more improved.

In general, this heat treatment is advantageously for at least 1 hour, preferably in the range of 20 to 200 hours, performed.

Furthermore, if the wire-shaped composite article during the above high-temperature short-time heat treatment surrounded by copper or a copper alloy, in particular sheathed, the copper or the copper alloy would be melted, giving a shape retention of the Material would make impossible. In this case it is necessary for the shape retention, the wire-shaped composite article with a substance of high melting point, such as niobium, Tantalum or vanadium, to enclose.

By performing the high-temperature short-time heat treatment to form an ultrafine, filamentary, superconducting Nb₃Al makes it possible to wire-shaped composite objects to obtain the excellent superconducting characteristics or characteristics in high magnetic fields or in alternating current magnetic fields.  

According to the present method, as stated above obtained a long composite wire-shaped article, such a Structure has an extremely large number of superfine, filamentary Nb₃Al with a diameter that is not greater than 1 micron, is embedded in a matrix, the made of oxygen-free copper, copper-nickel, copper-manganese Alloy or a mixture of the aforementioned exists, received. The composite article and its manufacturing method according to the present invention Invention have in particular the following advantages and characteristics:

• (i) Since the aluminum alloy is extremely fine Diameter of not greater than about 1 micron, finds the diffusion reaction during a low-temperature heat treatment within a short time (in the case an alloy that has a diameter of the order of magnitude of at least several tens of μm, is one Heat treatment at 1400 to 1800 ° C required), so that in this way filamentary Nb₃Al of ultrafine filament sizes is formed. As a result, a wire of high critical current density, which is an extremely important factor for its practical use.
• (ii) Since the filamentary Nb₃Al a higher upper has a critical magnetic field in comparison with Nb₃Sn or V₃Ga, as a practical superconducting materials of high magnetic Intensity used, it is to achieve high Magnetic fields suitable.
• (iii) Since the method according to claim 1 hardly requires an intermediate annealing, especially the provision a diffusion barrier in the wire during its compounding  required, are the production costs less than those involved in the production of Nb₃Sn or V₃Ga wires result.
• (iv) The produced by the method according to the invention Composite object is a wire, the ultrafine and homogeneous filamentary Nb₃Al with a diameter that is not greater than about 1 micron than the cores contains. Because such a ultrafine multi- or multi-filament wire very low ac losses The product can also be used with alternating current be used by commercial frequencies.
• (v) Because the wire-shaped composite article a higher critical temperature compared with already commercialized ultrafine Nb-Ti multi-filament Wire, it allows a greater temperature margin, when used with alternating current, and is advantageous.

More details are under Reference is made to the working examples given here.

Example 1

Rods of circular cross-section, each of which has a Had outside diameter of 7 mm and each made of Al, Al-0.1 At% Cu, Al-2 At% Cu, Al-3 At% Cu, Al-0.5 At% Cu-10 At% Mg, Al-2 at% Cu-0.5 at% Mg, Al-2 at% Cu-0.5 at% Mg-0.1 At% Zn-0.2 at% Li-0.1 at% Ag or Al-0.5 at% Cu-7 at% Mg-2 at.% Zn-1 at.% Li-1 at.% Ag was composed separately in a niobium tube of 14 mm outside diameter and 7 mm inner diameter inserted to eight types of composite bodies form, which were processed into wires, from each having an outer diameter of 1.14 mm, wherein processing into wires by such means as cold drawing, Grooving, die work, pulling od. Like., Was carried out. 120 strands each of the eight species thus obtained of single-core composite wires were joined together and in a niobium tube of 20 mm outside diameter and 14 mm inside diameter inserted to form composite filaments. Continue were made by corresponding cold drawing multi-core composite wires each got 1.14 mm outside diameter, the 120th Cores contained (hereinafter this product is referred to as "120- Core composite wire ", corresponding designations  are listed on each of the products that are listed below are used). Therefore, the core part had this composite wire has the same composition as those of Al or various aluminum alloys, as for the above specified rods of round cross section were used.

120 strands of the 120 core composite wire of the same composition were each assembled and inserted into a tube of oxygen-free copper of 20 mm outside diameter and 14 mm inside diameter. Composites formed in this manner were cold drawn, as before, into composite wires, each of which was a 1.24 mm OD 120 × 120 core composite wire. Again, 120 strands of each type of composite wire were assembled and each inserted into a tube of oxygen-free copper of 20 mm outside diameter and 14 mm inside diameter. The composites thus obtained were cold drawn as before, each with a 120 x 120 x 120 core composite wire of 0.3 to 10 mm outer diameter. The wires thus obtained were heat-treated at 600 to 1000 ° C to form filamentary Nb₃Al therein (that is, filaments of Nb₃Al). The critical temperature T _c and the critical current density J _{c of} the superconductivity were measured for each of the multi-filament products.

The wire with pure aluminum as the core could not be processed because the core is not its original shape could maintain. Those with Al-0.1 At.% Cu or Al-3 at.% Cu alloy as the core could be processed until the individual core diameter decreases to 1 μm was, but when the core diameter was made smaller, a break of the core took place. Of those who are cores Al-2 at.% Cu alloy, Al-0.5 at.% Cu-10 at.% Mg alloy,  Al-2 at.% Cu-0.5 at.% Mg alloy, Al-2 at.% Cu-0.5 At.% Mg-0.1 at.% Zn-0.2 at.% Li-0.1 at.% Ag alloy and Al-0.5 at.% Cu-7 at.% Mg-2 at.% Zn-1 at.% Li-1 at.% Ag alloy could have multifilament wires from an individual Core diameter of about 0.1 microns are produced.

Within the heat treatment temperature range of 700 to 1000 ° C, high T _c values of at least 14 K were measured. The T _c value was strongly dependent on the core diameter, and the high T _c values of at least 14 K could not be obtained unless the diameter became not larger than 1 μm.

Typical T _c values and J _c values obtained for each of the test samples are shown in Table 1 below. From the result shown in Table 1, it can be seen that the linear composite articles of the present invention have extremely high, practically promising J _c values. Further, it will be appreciated that since a large amount of oxygen-free copper is compounded into the articles, these articles are highly stable electromagnetically and are optimal for use in large-capacity conductors.

Table 1

Typical T _c values and J _c values of ultrafine multi-filament Nb₃Al wires with Al-Cu alloy core

example 2

By the method according to Example 1, one-core composite wires (outer diameter: 1.14 mm) were prepared, each with an Al-Cu alloy core of the composition shown in Table 2 below. 110 strands, each of the same type of wire, were assembled and inserted into a copper-nickel (Cu-20 at.% Ni) tube of 20 mm outer diameter and 14 mm inner diameter. The composite bodies formed in this way were cold-drawn into 110-core composite wire of 1.14 mm outside diameter. Each same type of wire strands was assembled and inserted into a like copper-nickel tube and subjected to cold drawing according to Example 1, and by repeating these compounding-drawing cycles, ultrafine multi-filament wires, each of 110x110x110 Strands of the aluminum alloy core had (individual core diameter: 0.03 microns), successfully produced. In the typical of these wires, T _c and J _c values were measured by the methods approximately similar to those used in Example 1, with the results obtained shown in Table 2. In the ultrafine multi-filament wires in which the matrix is copper-nickel of high electrical resistance as in the present case, coupling current between superconducting filaments is cut off to make AC losses very low. As a result, the wires can be used for AC of commercial frequencies.

Table 2

Typical T _c - and J _c values of ultrafine Multithread wires of Nb₃Al with Al-Cu-based alloy core, compounded with copper-nickel

example 3

Rods of circular cross-section, each of which has a Outer diameter of 6 mm and each of Al, Al-3 At .-% Mg, Al-6 at.% Mg, Al-10 at.% Mg or Al-15 at.% Mg was or existed, were separately in a niobium tube of 12 mm outside diameter and 6 mm inside diameter inserted. The composites formed in this way were converted to wires of 1.14 mm outer diameter such cold drawing means as grooving, die cutting, Pull od. Like., Processed. 110 strands of each of the up This one-core composite wires obtained were assembled and each in a niobium tube of 20 mm outside diameter and 14 mm inner diameter inserted to composite filaments to build. Next were by appropriate cold drawing Multi-core composite wires of 1.14 mm outer diameter, which contained 110 cores (below) Product referred to as "110 core composite wire"). Therefore had the core part of this composite wire the composition, the identical to that of Al or one of the different ones Al-Mg alloys were those specified for the above Rods of round cross section had been used.

110 strands of the 110-core composite wire of the same composition were each assembled and inserted into an oxygen-free copper tube of 20 mm outer diameter and 14 mm inner diameter. The composites formed in this manner were cold drawn as before into composite wires, each 110 × 110 core composite wire of 1.14 mm outside diameter. Again, 110 strands of the same type of composite wire were assembled and inserted into an oxygen-free copper tube of 20 mm outside diameter and 14 mm inside diameter. The composites obtained in this manner were cold drawn as before, each with a 110 × 110 × 110 core composite wire of 0.3 to 10 mm outer diameter. The wires thus obtained were heat-treated at 600 to 1000 ° C to form filamentary Nb₃Al therein. The critical temperature T _c and the critical current density J _{c of} the superconductivity of each of the multifacament products were measured.

The wire with pure aluminum as the core could not be cold drawn be because the core was deformed than its Core diameter was reduced beyond 50 microns. The processing of wires with Al-3 at .-% Mg alloy or Al-15 at.% Mg alloy as the core was wearable until possible the individual core diameter was reduced to 1 μm, but when the core diameter was made smaller, found Nuclear break instead. Of those containing nuclei of Al-6 at% Mg- Alloy and Al-10 at.% Mg alloy could have ultrafine Multifabric wires of individual core diameter be prepared, which was in the range of 1 micron to 0.03 microns.

Within the heat treatment temperature range of 700 to 1000 ° C, high T _c values of at least 14 K were measured. As the heat treatment temperature exceeded 1000 ° C, the matrix melted out of oxygen-free copper. The T _c value strongly depended on the core diameter, and the high T _c values of at least 14 K could not be obtained unless the diameter became not larger than 1 μm.

The critical temperatures (T _c ) and critical current densities (J _c ) of typical composite articles obtained from each of these samples were measured, with the results shown in Table 3 below. It can be seen from the data in this Table 3 that these composite articles had extremely high, industrially valuable J _c values. Further, since the wires have been compounded with a large amount of oxygen-free copper, they are electromagnetically highly stabilized, and they are suitable as large-capacity conductors.

Table 3

Typical T _c and J _c values of ultrafine multifilament wires of Nb₃Al with Al-Mg alloy cores

example 4

Using rods of circular cross-section, each having an outer diameter of 6 mm and each consisting of Al-3 at.% Mg, Al-6 at.% Mg, Al-10 at.% Mg or Al. 15 at.% Mg were combined, one-core composite wires (1.14 mm outside diameter) were prepared in the manner corresponding to Example 3. 110 strands each of the same type of single-core composite wire were assembled and each inserted into a tube of copper-nickel (Cu-20 at.% Ni alloy) of 20 mm in outer diameter and 14 mm in inner diameter to form composite materials. which were processed by cold drawing to 110 core composite wires of 1.14 mm outside diameter. Further repetition of the compounding into a copper-nickel tube and cold drawing cycle according to Example 2, ultrafine multifilament wires each having 110 × 110 × 110 strands of the aluminum alloy cores (core diameter: about 0.03 μm) , successfully produced. The wires had T _c and J _c values as shown in Table 4. In such ultrafine multifacament wires having a copper-nickel matrix of high electrical resistance, coupled currents flowing between superconducting filaments are cut off, so that the AC losses are drastically reduced. As a result, the wires become usable for alternating current of commercial frequencies.

Table 4

Typical T _c and J _c values of ultrafine multifilament wires of Nb₃Al with Al-Mg base alloy core compounded with copper-nickel

example 5

Using rods of circular cross section, each of which had an outer diameter of 6 mm and each made of the following alloys: Al-3 at% Zn, Al-5 at% Zn, Al-7 at% Zn, Al-10 at% Zn, Al-3 at% Li, Al-6 at% Li, Al-10 at% Li, Al-15 at% Li, Al-3 at% Ag, Al-5 at% Ag, Al-7 at% Ag or Al-10 at% Ag, were compound processing cycles according to the example 3 repeated. In this way composite wires, each of which is 110x110x110 strands of respective ones Aluminum alloy cores had been made. As Al-3 At% Zn, Al-10 at% Zn, Al-3 at% Li, Al-15 at% Li, Al-3 at.% Ag and Al-10 at.% Ag alloys used as the core However, the composite wires showed fractures during cold drawing, after the core diameter to less was reduced by 1 μm, and it was no further Pulling possible. On the other hand, when Al-5 at.% Zn, Al-7 at.% Zn, Al-5 at.% Li, Al-6 at.% Li, Al-10 at.% Li, Al-5 at.% Ag. and Al-7 at.% Ag alloys are used as the core material cold drawing was possible until the core diameter about 0.03 microns.

When the wires were heat treated at temperatures ranging from 700 to 1000 ° C, high T _c values of at least 14 K were obtained. Exceeding the heat treatment temperature of 1000 ° C, the oxygen-free copper matrix was melted, and the T _c value strongly depended on the core diameter, with high T _c values of at least 14 K being obtainable only at the core diameters were reduced to not more than 1 μm in accordance with the phenomenon observed with Al-Mg alloy cores.

Typical T _c and J _c values obtained in each of the tests are given in Table 5 below. From the results given in Table 5, it can be seen that the wires had very high and industrially useful J _c values. Further, similarly, in the case of the products obtained in Example 5, these wires are suitable for use as large-capacity conductors because they are electromagnetically due to the presence of a large amount of oxygen-free copper compounded therein are highly stabilized.

Table 5

Typical T _c and J _c values of ultrafine multi-filament Nb₃Al wires with Al-Cu, Al-Li, and Al-Ag alloy cores

example 6

The most important point in the production of Nb-Al composite objects that the ultrafine structure like the product according to the invention by compounding processing, is that the aluminum alloy the curing characteristics or -kenndaten should, which those of niobium similar in processing. The investigation of the hardening Characteristics of aluminum based Al-Mg-Zn-Li-Ag alloys showed that when the added amounts of each of the elements are small, the cure characteristics by the total amount of addition of these other elements to aluminum be determined. If, in turn, this total of the Add addition of other elements exceeds 4 at.% the hardening characteristics of the alloy considerably depending on the type of element, of the largest amount was added. It became a Ten denz observes that the alloys then, if two to four types of elements were added, became tougher as in the case of adding a single element.

Bars of circular cross section each composed of the following alloy: Al-6 at.% Mg-1 at.% Zn-1 at.% Li-1 at.% Ag, Al-1 at.% Mg-4 at.% Zn-1 at.% Li-1 at.% Ag, Al-1 at.% Mg-1 at.% Zn-6 at.% Li-1 at. % Ag or Al-1 at.% Mg-1 at.% Zn-1 at.% Li-4 at.% Ag was used separately as the core and through the repeated compounding / drawing cycles According to Example 3, composite wires were prepared each having 110 × 110 × 110 strands of aluminum alloy core (core diameter: 0.1 μm). By heat-treating these wires at 800 ° C. for 1 hour, T _c and J _{c were} obtained as shown in Table 6 below.

Table 6

T _c and J _c values of multi-filament Nb₃Al wires with various five-component aluminum alloys

example 7

Using a rod of circular cross-section and 6 mm outer diameter, each made of one of the following alloys: Al-2 at.% Cu-2 at.% Ge, Al-2 at.% Cu-4 At% Ge, Al-2 At% Cu-2 At% Si, Al-2 At% Cu-4 At% Si or Al-2 At% Ge-2 At. % Si, and tubes of 14 mm in outer diameter and 7 mm in inner diameter each composed of Nb-3 at% Ge alloy or Nb-3 at% Si alloy were compounded by means of the method described in U.S. Pat each of which had 120 × 120 × 120 strands of aluminum alloy core (core diameter: 0.1 μm). When the composite wires were heat-treated at 800 ° C. for 5 hours, high T _c and J _c values were obtained as shown in Table 7 below.

Table 7

Typical T _c - and J _c values of multi-strands wires of Nb₃Al, which Si and Ge are added

example 8

Using a rod of circular cross section and 6 mm outer diameter, each made of one of the following alloys: Al-6 At .-% Mg-2 At .-% Ge, Al-6 At .-% Mg -4 at.% Ge, Al-6 at.% Mg-2 at.% Si, Al-6 at.% Mg-4 at.% Si or Al-6 at.% Mg-2 At .-% Ge-2 at.% Si, and tubes of 12 mm outer diameter and 6 mm inner diameter, each composed of Nb-3 at.% Ge alloy or Nb-3 at.% Si alloy Composite wires were made by the method according to Example 3, each of which had 110 × 110 × 110 strands of aluminum alloy core (core diameter: 0.1 μm). When the composite wires were heat-treated at 800 ° C. for 1 hour, high T _c and J _c values were obtained as shown in Table 8 below. Further, when 5 at.% Or more of Si and Ge were added in total to the aluminum alloy or niobium, the workability of the system deteriorated, and the multi-filament ultrafine wire could not be produced.

Table 8

Typical T _c - and J _c values of multi-strands wires of Nb₃Al, which Si and Ge are added

example 9

When the amounts of other components that contribute to the formation alloy added to aluminum are relatively small such as Al-0.1 at.% Cu, Al-2.5 at.% Mg, Al-2.5 at.% Zn, Al-2.5 at.% Li, Al-2.5 at.% Ag, Al-1 at.% Ag-0.7 at.% Ge, Al-1 at.% Mg-0.7 at.% Si, could have its Vickers hardness of about  50 to 100, if these alloys one Solution treatment at 400 to 550 ° C for at least 1 Hour and then quenching in water and annealing at room temperature to 200 ° C for at least 1 hour were subjected. In this way their hardness became equivalent that of Nb, and the alloys could as core until be processed to the core diameter of 0.1 microns.

Table 9

Typical T _c and J _c values of ultrafine multi-filament Nb₃Al wires using tempered aluminum alloy

example 10

The manufacturing steps of Example 3 were repeated, except that a rod of circular cross-section was used as the core composed of Al-7 at.% Mg alloy. In this way, a wire-shaped composite article was obtained, which had filamentary Nb₃Al cores, each having a diameter of 0.1 microns. The outer diameter of this article was 0.7 mm. When a tensile stress was applied to this article and the J _c value was measured, no occurrence of a crack was observed in the Nb₃Al filaments up to the elongation of 1.3 to 1.5%, and the deterioration in the superconducting characteristics and Key data was small. This value shows a very excellent characteristic of the product of the invention in comparison with other commercial superconducting Nb₃Sn or V₃Ga wires which showed cracks in the superconducting filaments under an elongation of about 0.6% and a rapid deterioration in their superconducting characteristics or characteristic values. As a result, the composite articles of the present invention have excellent resistance to tensile stress, which is a very advantageous property for industrial use.

example 11

A rod of circular cross section and 6 mm outer diameter composed of Al-6 at.% Mg was inserted into a niobium tube of 12 mm in outer diameter and 6 mm in inner diameter to form a composite body, which became a wire of 1.14 mm outside diameter by such cold drawing means, such as grooved rolls, die processing, drawing od. Like., Was processed. 110 strands of this single core composite wire were assembled and inserted into a niobium tube of 20 mm outside diameter and 14 mm inside diameter to form a multi-core composite, which was then cold drawn into a 1.114 mm outside diameter 110 core composite wire was processed. Repeating the steps of assembling 110 strands of this 110-core composite wire twice, inserting the composition into a niobium tube, and drawing the resulting multi-core composite body was a 110 × 110 × 110 core composite wire of 0.3 to 10 mm outer diameter receive. This wire was heat-treated by direct electric current conduction in liquid nitrogen while being agitated to be subjected to heating at 1 to 100 kW / cm³ and at least about 1400 ° C for 0.01 to 10 seconds and thereafter cooled immediately Nb₃Al filaments were formed in the wire. In this way, a plurality of wires in which the cores each had a diameter of not more than 0.5 μm were prepared. For each of the wires, the critical temperature T _c and the critical current density J _{c of} the superconductivity were measured. The results are shown in Table 10 below.

Table 10

When the core diameter was 0.3 μm or less, a high T _c of at least 17 K was obtained when the energy applied in the heating time was of the order of 100 kJ / cm 3. When the wires were given a post-heat treatment of several days at about 700 ° C, they exhibited an even higher T _c value of at least 18 K. The J _c value depended on the core diameter, and a high J _c value of at least 10⁵ A / cm³ (4.2 K, 10 T) was not obtained unless the core diameter was reduced to 0.3 μm or less. The samples that had T _c <18 K showed H _c2 (4.2 K, <30 T).

These wires had extremely high superconducting characteristics characteristics and if after the post-heating treatment copper plated, they showed a very high electromagnetic Stability.

example 12

The Al-6 at.% Mg rod used in Example 11 was replaced in each run by a rod of circular cross section, each having the following composition: Al-3 at.% Mg, Al. 10 at.% Mg, Al-15 at.% Mg, Al-5 at.% Zn, Al-10 at.% Zn, Al-5 at.% Li, Al-10 at.% Li, Al-4 at.% Ag, Al-8 at.% Ag, Al-2 at.% Cu, Al-5 at.% Cu, Al-5 at.% Mg-5 At. % Zn, Al-5 at% Zn-5 at% Li, Al-5 at% Ag-2 at% Cu or Al-3 at% Ag-2 at% Ge, and ultrafine multi-core wires having a core diameter of not more than 0.5 μm from the structure that aluminum alloy filaments were inserted into a niobium matrix were prepared by the method according to Example 11. The wires were heat treated by direct current passage for a very short period of not more than 10 seconds. When the wires were further post-baked at 700 ° C, all of them had a T _c of at least 17 K, an H _c2 of at least 30 T, and a J _c (4.2 K, 10 T) of at least 1 × 10⁵ A / cm².

example 13

A rod of circular cross-section of 6 mm outer diameter, which was composed of Al-6 at.% Mg was in a niobium tube of 12 mm outer diameter and 6 mm inner diameter to form a composite body inserted, which to a wire of 1.14 mm outside diameter by such  Cold drawing means, such as grooving, die-cutting, Pull od. Like., Has been processed. 110 strands of this One-core composite wire was assembled and put into one Tantalum tube of 20 mm outer diameter and 14 mm inner diameter inserted to form a multi-core composite body, then to a 1.11 mm 110 core composite wire Outer diameter was processed by cold drawing. By a twofold repetition of the steps of composing of 110 strands of this 110-core wire, inserting the composition into a tantalum tube and pulling the resulting Multi-core composite body became a 110 × 110 × 110 core Composite wire of 0.3 to 10 mm outside diameter obtained. This wire, which has a core diameter of not larger than 0.5 microns, was through direct current passage heat treated in liquid nitrogen, while he was moved to a heat during Exposed for 0.2 seconds and then immediately cooled to be formed so that Nb₃Al filaments in the wire were.

After a post-heat treatment of these wires at 700 ° C, their critical temperature T _c and their critical current density J _c of superconductivity were measured. In this example, the results were also approximately the same as those of Example 11 in which niobium tubes were used. When the tantalum tubes were again replaced by vanadium tubes, the superconducting characteristics of the resulting wires remained almost unchanged.

example 14 (Measurement of maximum allowable elongation)

Example 1 was repeated but with the modification that a rod of circular cross-section of 7 mm outer diameter and a composition of Al. 5 At .-% Mg alloying tion was used to form a composite wire. This composite wire was heat treated at 750 ° C for 20 hours, and its J _c value was measured under tension in a magnetic field of 7T at 4.2K. With a tensile elongation of 0.5%, the J _c value of this wire showed a reduction of 4%. This is a far lower rate of the wearer, compared to the strong decrease of about 15%, which showed ultrafine Nb3Sn multi-core wire under the same tensile strain. When even higher elongation was used, the maximum allowable elongation at which the filaments of the superconducting compound broke and could no longer be used was 1.2 to 2% in this ultrafine Nb₃Al multi-core wire, while that of ultrafine Nb₃ Sn multi-core wire is about 0.5 to 0.8%. This small decrease of the J _c -value under tensile elongation or the voltage and the large maximum permissible elongation show that, when the composite articles according to the present invention supra direct the magnets used, there is less necessity of considering the influence of the electromagnetic force That is, the design of the magnet is easier, and further, it is also easier because of the handling of the wires, and the practical value of the present invention is extremely high.

Claims (21)

A method of making a wire-shaped superconductive composite article comprising the steps of:

• 1) collecting a number of strand-like Verbundele elements ( 3 , 4 ), which consist of a matrix ( 1 ) of niobium containing one or more strands ( 2 ) of an aluminum alloy, which has a higher hardness than aluminum;
• 2) inserting said plurality of composite elements ( 3 , 4 ) into a tube ( 5 , 6 ) of copper, a copper alloy, niobium, tantalum or vanadium;
• 3) pulling the tube ( 5 , 6 ) together with the Verbundele elements ( 3 , 4 ) to a composite filament;
• 4) inserting a number of composite filaments into a tube of copper, a copper alloy, niobium, tantalum or vanadium;
• 5) pulling the tube together with the composite filaments into a new composite filament;
• 6) repeating the process steps ( 4 ) and ( 5 ) until the strand ( 2 ) of the aluminum alloy has a thickness of 1 μm or less; and
• 7) heat-treating the obtained composite article to form the superconducting compound Nb₃Al.

2. A method of making a wire-shaped superconductive composite article comprising the steps of:

• 1) collecting a number of strand-like Verbundele elements ( 3 , 4 ), which consist of a matrix ( 1 ) of aluminum alloy containing one or more strands ( 2 ) of niobium, wherein the Aluminiumle alloy has a higher hardness than aluminum, and surrounding the composite element ( 3 , 4 ) with a coating of niobium, tantalum, vanadium or a mixture of at least two thereof;
• 2) inserting said plurality of composite elements ( 3 , 4 ) into a tube ( 5 , 6 ) of copper, a copper alloy, niobium, tantalum or vanadium;
• 3) pulling the tube ( 5 , 6 ) together with the Verbundele elements ( 3 , 4 ) to a composite filament;
• 4) inserting a number of composite filaments into a tube of copper, a copper alloy, niobium, tantalum or vanadium;
• 5) pulling the tube together with the composite filaments into a new composite filament;
• 6) repeating process steps ( 4 ) and ( 5 ) until the strand ( 2 ) of niobium has a thickness of 1 μm or less; and
• 7) heat-treating the obtained composite article to form the superconducting compound Nb₃Al.

3. Method of making a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the aluminum alloy we at least one metal consisting of Cu, Mg, Zn, Li and Ag contains the group. 4. Method of making a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the copper or the copper Alloy made of oxygen-free copper, copper-nickel, Copper-manganese alloy and copper-magnesium alloy best group has been selected. 5. Method of making a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the aluminum alloy from about 0.1 to about 15 at% of at least one of selected from Mg, Zn, Li and Ag group selected metal contains. 6. Method of making a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the aluminum alloy from about 2 to about 15 atomic% of at least one of the Mg, Zn, Li and Ag existing group selected metal ent holds. 7. Method of making a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the aluminum alloy from about 3 to about 10 at% of at least one of selected from Mg, Zn, Li and Ag group selected metal contains.   8. Method of making a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the aluminum alloy contains about 0.5 to about 3 atomic% of Cu. 9. Method of making a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the aluminum alloy contains about 1 to about 2 atomic% of Cu. 10. Method of making a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the aluminum alloy contains not more than 4 atom% of Si and / or Ge. 11. Method of making a wire-shaped supra conductive composite article according to any one of the preceding claims, characterized characterized in that the niobium is not more than 4 atom% Si and / or Ge contains. 12. Method of making a wire-shaped supra conductive composite article according to any one of the preceding claims, characterized characterized in that the pulling by cold pulling is effected. 13. Method of making a wire-shaped supra conductive composite article according to any one of the preceding claims, characterized characterized in that the heat treatment at Temperatures between about 700 ° C and about 2300 ° C causes becomes. 14. Method of making a wire-shaped supra conductive composite article according to claim 13, characterized  characterized in that the heat treatment at Temperatures between about 750 ° C and about 2000 ° C causes becomes. 15. Method for producing a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the heat treatment is internal for about 10 seconds at temperatures between about 1100 ° C and about 2300 ° C is effected. 16. Method of making a wire-shaped supra composite conductive article according to claim 1 or 2, characterized characterized in that the heat treatment is internal half of about 5 seconds at temperatures between about 1400 ° C and about 2000 ° C is effected. 17. A method for producing a wire-shaped supra-conductive composite article according to any one of the preceding claims, characterized in that the process steps ( 4 ) and ( 5 ) are repeated until the obtained in step ( 7 ) superconducting compound Nb₃Al Fila elements with an average diameter of 0.03 microns to 1 micron. 18. A method for producing a wire-shaped supra-conductive composite article according to claim 17, characterized in that the process steps ( 4 ) and ( 5 ) are repeated until the obtained in step ( 7 ) superconducting compound Nb₃Al filaments with a mean diameter from about 0.05 μm to about 0.5 μm. 19. A method for producing a wire-shaped supra-conductive composite article according to any one of the preceding claims, characterized in that the process steps ( 4 ) and ( 5 ) are repeated until the composite article obtained in process step ( 7 ) has an arrangement of about 100,000 to about 10 000 000 filaments of Nb₃Al contains. 20. Method for producing a wire-shaped supra conductive composite article according to any one of the preceding claims, characterized characterized in that the composite article is in a mean diameter of about 0.2 mm to about 5 mm ago is provided. 21. Use of one of claims 1 to 20 manufactured composite article in a superconducting Transformer, in a superconducting generator, in one superconducting energy storage device, in a supra conductive magnet for a nuclear fusion furnace, in one superconducting magnets for a precision magnetic field or in a superconducting magnet for alternating current.