JPH11250748A - Manufacture of nb3al based superconducting wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire rod which is free from disconnection even if it is elongated by severe digressive and plastic works, has a high critical magnetic field, and is superior in distortion resistance by constituting a wire rod in such a state that an Nb-Al bond integral composite sheet which is composed of an Nb sheet and an Al sheet of a prescribed molecular weight ratio is wound around an Nb rod. SOLUTION: An Nb sheet layer 1 is cladded on both surfaces of an Al sheet layer 2 so that an Nb-Al bond integral composite sheet composed of an Nb-Al 3-layer clad sheet 4 is provided. This composite sheet can be formed by welding or sticking the Nb sheet to the Al sheet by adhesive. In this case, it is preferable that the thicknesses of the Nb sheet and the Al sheet are so constituted as to be Nb/Al=3.0-4.5/1 in terms of the molecular weight ratio. This Nb-Al 3-layer clad sheet 4 is wound around the Nb rod by being used as a forming material of Nb3 Al and the obtained Nb-Al composite sheet winding wire body is degressively and plastically worked to be a wire rod, heat treated, and diffusedly reacted so that the Nb3 Al based superconducting wire can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an Nb ₃ Al-based superconducting wire. More specifically, the present invention relates to N used as a superconducting wire for magnet coils such as a fusion magnet coil, an energy storage magnet coil, and a high magnetic field magnet coil for studying physical properties.
The present invention relates to a method for manufacturing a b ₃ Al-based superconducting wire.

[0002]

2. Description of the Related Art Superconducting wires are roughly classified into metal-based superconducting wires and ceramic-based superconducting wires.

[0003] Although ceramic-based superconducting wires that can be used at room temperature are being found, their superconducting stability on the other hand is lacking, and it is difficult to increase the capacity in terms of capacity.

On the other hand, metal-based superconducting wires are roughly classified into alloy-based superconducting wires and intermetallic compound-based superconducting wires.

[0005] Alloy-based superconducting wires include Zr-containing Nb-based superconducting wires and Ti-containing Nb-based superconducting wires. Since this kind of alloy-based superconducting wire is an alloy, it can be easily drawn to an arbitrary size, so that it is widely used.

As an intermetallic compound superconducting wire, Nb ₃ A
l system there is a superconducting wire or Nb ₃ Sn-based superconducting wire.

This intermetallic compound superconducting wire has excellent superconducting stability, and can have a large capacity. In particular, the Nb ₃ Al-based superconducting wire has a higher critical magnetic field than the Nb ₃ Sn-based superconducting wire, the Zr-containing Nb-based superconducting wire, the Ti-containing Nb-based superconducting wire, and can withstand use up to a high magnetic field. Excellent strain resistance.

For these reasons, Nb ₃ Al superconducting wires are suitable as superconducting wires for large-capacity, high-magnetic-field gnet coils, such as nuclear fusion magnet coils and energy storage magnet coils, and their practical use is strongly desired. I have.

However, this Nb ₃ Al-based superconducting wire is an intermetallic compound-based superconducting wire, and thus it is difficult to uniformly form the intermetallic compound, and this greatly hinders practical use. That when you try drawing from making advance Nb ₃ Al intermetallic compound, the Nb ₃ Al intermetallic compound is difficult because of poor drawing properties. vice versa,
A metal wire composed of two layers of metal Nb and metal Al is manufactured in advance, then drawn to a predetermined size, and heat-treated to give Nb ₃
When an intermetallic compound of Al is produced, it is difficult to control the ratio of the two layers of metal Nb and metal Al, and it is also difficult to uniformly produce the intermetallic compound.

That is, as a conventional method for producing a Nb ₃ Al-based superconducting wire, a jelly roll method is known. (For example, JP-A-4-132113, JP-A-6-366)
An outline of the jelly roll method is as follows.

First, a first sheet layer made of an Nb sheet or a sheet containing Nb is overlapped with a second sheet layer made of an Al sheet or a sheet containing Al to produce an Nb · Al overlap sheet.

The thickness ratio of the first sheet layer made of an Nb sheet or a sheet containing Nb to the second sheet layer made of an Al sheet or a sheet containing Al is Nb ₃ A.
The atomic weight ratio is set to 3: 1 so that 1 can be obtained.

Next, the Nb · Al laminated sheet obtained above is wound around a metal bar, or the Nb · Al
-Obtain an Al wrapped sheet wrap.

FIG. 7 is a cross-sectional explanatory view showing a state in which an Nb / Al wrapped sheet is manufactured by winding an Nb / Al wrapped sheet around the outer periphery of a metal rod.

In FIG. 7, 1 is an Nb sheet layer and 2 is Al
The sheet layer 3 is an Nb bar.

Next, by inserting the Nb · Al wrapped sheet obtained in the above into a long metal tube,
-Obtain an Al overlapping sheet bus.

Next, the Nb · Al laminated sheet wire obtained by the above is extruded, reduced in surface area such as drawing, and plastically processed to form a Nb · Al laminated sheet wire of a predetermined size.

Finally, Nb of a predetermined size obtained by
A first sheet layer made of an Nb sheet or a sheet containing Nb and a second sheet layer made of an Al sheet or a sheet containing Al are subjected to a diffusion reaction by thermally treating the Al laminated sheet wire at a predetermined temperature, and ₃ Al-based superconducting wire.

However, the second sheet layer made of an Al sheet or a sheet containing Al in the above-mentioned surface reduction and plastic working step needs to be thinned to about 100 nm in order to increase the diffusion reactivity. In this way, the surface reduction and plastic working to reduce the thickness to about 100 nm is extremely severe,
_This is a major obstacle to the practical use of 3Al-based superconducting wires.

That is, with respect to the Nb · Al laminated sheet bus, the second sheet composed of the Al sheet or the sheet containing Al is used.
Severe surface reduction such as thinning the sheet layer to about 100 nm,
If an Nb / Al laminated sheet wire having a predetermined dimension is formed by plastic working, disconnection or the like frequently occurs in the process, and as a result, a long Nb / Al laminated sheet wire having a predetermined dimension cannot be obtained.

[0021]

SUMMARY OF THE INVENTION The present invention has been made in view of such a point, and an object of the present invention is to solve the above-mentioned drawbacks of the prior art and to carry out severe surface reduction and plastic working. Even if the wire does not break, a long wire can be formed as a result, and the obtained wire has a high critical magnetic field and can withstand use up to a high magnetic field, and furthermore has excellent strain resistance Nb ₃ Al-based material. An object of the present invention is to provide a method for manufacturing a superconducting wire.

[0022]

SUMMARY OF THE INVENTION The gist of the present invention is to use an Nb / Al joint integrated composite sheet obtained by joining and integrating an Nb sheet and an Al sheet as a material for forming Nb ₃ Al. In the method for producing an Nb ₃ Al-based superconducting wire.

In the present invention, as the Nb / Al bonded integrated composite sheet, a sheet formed by cladding an Nb sheet and an Al sheet, a sheet formed by welding an Nb sheet and an Al sheet, and a sheet formed by welding an Nb sheet and an Al sheet are used. For example, there is one bonded by an adhesive.

In the present invention, the Nb / Al bonded integrated composite sheet may be an Nb sheet layer of 3.0 to 4.5 / A.
It is preferable to use a layer whose thickness is adjusted so as to have an atomic weight ratio of 1 sheet layer 1.0.

Now, when the Nb / Al composite sheet bus bar is extruded as described above, and the surface of the Nb / Al composite sheet wire having a predetermined size is formed by reducing the area by drawing or the like and performing plastic working, the workability is as follows. Depends on factors.

(1) Uniformity of the material of each constituent material Each constituent material has a non-metallic intervening compound which deteriorates workability,
It is important that no intermetallic compound, foreign matter or the like is mixed.

(2) Similarity of Mechanical Properties between Constituent Materials As for the workability, the more similar the mechanical properties of each constituent material, such as deformation resistance and elongation, the more uniform the deformation.

For example, there is a large difference in deformation resistance between Nb and Al, and it is difficult to flow uniformly. Therefore, a non-uniform flow portion occurs in the longitudinal direction, and as a result, Nb · Al
Breakage of the composite sheet wire is likely to occur frequently.

(3) Adhesion between constituent materials In order to uniformly apply a processing stress between the constituent materials via a working tool, it is desirable that the constituent materials are in good contact with each other.

When a processing stress is applied between constituent materials having poor adhesion via a processing tool, slip occurs between the constituent materials, and a uniform material flow cannot be achieved. In particular, when there are many interfaces as in the jelly roll method, slippage is likely to occur between the constituent materials, and as a result, disconnection of the Nb / Al composite sheet wire tends to occur frequently.

That is, the method for producing an Nb ₃ Al-based superconducting wire of the present invention solves the above-mentioned problems (1) to (3) at once by using an Nb / Al bonded integrated composite sheet as the Nb / Al composite sheet. It is a solution.

In other words, when manufacturing the Nb / Al composite sheet wound wire, instead of winding an independent Nb sheet and an independent Al sheet, an integrated Nb sheet and an Al sheet are wound in advance. It is manufactured.
In other words, the Nb / Al clad sheet can solve the above-mentioned problems (1) to (3) at once because a metallic bond is obtained between Nb and Al and can be processed as a single metal sheet.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method for producing an Nb ₃ Al-based superconducting wire according to the present invention will be described with reference to the drawings.

Example 1 (1) First, an Nb / Al three-layer clad sheet was obtained by cladding an Nb sheet layer on both sides of an Al sheet layer.

FIG. 1 shows the thus obtained N of the present invention.
Nb used in Example 1 of the method for producing a b ₃ Al-based superconducting wire
-It is the longitudinal cross-sectional view which showed the Al three-layer clad sheet. In FIG. 1, 1 is an Nb sheet layer, 2 is an Al sheet layer, and 4 is an Nb.Al clad sheet.

That is, the Nb · Al three-layer clad sheet 4 used in one embodiment of the method for producing an Nb ₃ Al-based superconducting wire of the present invention is formed by cladding one layer of an Nb sheet on both sides of an Al sheet layer 2. It is. Where Nb / Al / Nb
Is 1.5 / 1.0 / 1.5 in atomic weight ratio.

This Nb.Al three-layer clad sheet 4 was rolled to a thickness of 0.23 mm.

N rolled to a thickness of 0.23 mm
Each thickness of the b · Al three-layer clad sheet 4 is Nb0.1
mm / Al 0.03 mm / Nb 0.1 mm. That is, 0.
The Nb / Al three-layer clad sheet 4 rolled to 23 mm is formed by cladding a 0.1 mm Nb sheet layer 1 on both sides of a 0.03 mm thick Al sheet layer 2. .

(2) Next, the thus obtained 0.03 mm
Nb · A clad on both sides of a thick Al sheet layer 2 by sandwiching it with a 0.1 mm Nb sheet layer 1
l The three-layered clad sheet 4 is formed with a diameter of 6 mm and a length of 150 mm.
Was wound around an Nb rod to obtain an Nb / Al composite sheet wound wire.

FIG. 2 is an explanatory sectional view showing the winding state.

FIG. 3 is a cross-sectional view of the obtained Nb / Al composite sheet wound wire.

2 and 3, 1 is an Nb sheet layer,
Reference numeral 2 denotes an Al sheet layer, 3 denotes an Nb rod, 4 denotes an Nb / Al three-layer clad sheet, and 5 denotes an Nb / Al composite sheet wound wire.

(3) Next, the outer diameter φ28.5 mm and the inner diameter φ2
A Cu-coated Nb tube was obtained by inserting a Nb tube having an outer diameter of 24.6 mm, an inner diameter of 22.3 mm, and a length of 150 mm into a Cu tube having a length of 5 mm and a length of 170 mm.

Next, the Nb / Al composite sheet wrapping wire 5 obtained in the above (2) was inserted into the Cu-coated Nb tube thus obtained to obtain an Nb / Al composite sheet bus. .

FIG. 4 is a cross-sectional view of the bus bar of the Nb / Al composite sheet thus obtained.

In FIG. 4, reference numeral 5 denotes a wire wound around an Nb / Al composite sheet, 6 denotes a Cu tube, 7 denotes an Nb tube, and 8 denotes a bus of an Nb / Al composite sheet.

(4) Next, both ends of the obtained Nb / Al composite sheet bus 8 were sealed to obtain a monofilament billet.

(5) Next, the monofilament billet obtained in the above (4) was subjected to hydrostatic extrusion at room temperature to obtain a monofilament wire having a diameter of 12 mm.

(6) Next, the monofilament wire obtained in the above (5) was drawn with a hexagonal die to have a side length of 2.7.
A 7 mm hexagonal section monofilament wire was obtained. Then, the obtained hexagonal cross-section monofilament wire was straightened and straightened, cut into a length of 150 mm, further washed and dried.

(7) Next, a copper wire having a diameter of φ12 mm was prepared and drawn with a hexagonal die to obtain a hexagonal section copper wire having a side length of 2.77 mm. Then, the hexagonal section copper wire obtained here was straightened, cut to a length of 150 mm, and further washed,
Dried.

(8) Next, the multifilament is obtained by arranging 48 hexagonal cross-section monofilament wires obtained in (6) around one copper wire in hexagonal cross section obtained in (7) above. I got

(9) Next, the outer diameter φ28.5 mm and the inner diameter φ2
In a 3.4 mm, 170 mm long multi-Cu tube, the above (8)
The multifilament billet was obtained by inserting the multifilament obtained in the above.

FIG. 5 is an explanatory perspective view of the multifilament thus obtained.

In FIG. 5, reference numeral 9 denotes a hexagonal cross-section monofilament wire, 10 denotes a multi-coated Cu tube 11 denotes a multi-filament.

(10) Next, the multifilament billet obtained in the above (9) was heated to 400 ° C. and then extruded with hydrostatic pressure to have an outer diameter of 12 mm.

(11) Next, the outer diameter φ1 obtained in the above (10)
A 2 mm multi-filament billet was drawn through a wire drawing machine to obtain a multi-filament wire having an outer diameter of 0.6 mm and a length of 260 m.

(12) Next, the multifilament wire obtained in the above (11) was subjected to a diffusion reaction at 800 ° C. to obtain an Nb ₃ Al-based superconducting wire of Example 1.

(13) The Nb ₃ Al-based superconducting wire of Example 2 thus obtained is as long as 260 m.
In addition, although not shown as data, it has a high critical magnetic field and can withstand use up to a high magnetic field, and furthermore, has exhibited excellent resistance to distortion.

(Example 2) (1) First, an Al sheet and an Nb sheet are clad and rolled by a rolling roll so that the thickness ratio of Al / Nb becomes 1/3, thereby forming an Nb / Al double-layer clad sheet. I got

FIG. 2 shows the thus obtained N of the present invention.
Nb used in Example 2 of the method for producing b ₃ Al-based superconducting wire
-It is the longitudinal cross-sectional view which showed the Al two-layer clad sheet.

In FIG. 2, 1 is an Nb sheet layer, 2 is Al
The sheet layer 12 is a Nb.Al two-layer clad sheet.

The Nb / Al two-layer clad sheet 12 was rolled so as to have a thickness of 0.23 mm.

N rolled to a thickness of 0.23 mm
b · Al double-layer clad sheet 12 has a thickness of Al0.
03 mm / Nb 0.20 mm.

(2) Next, the thus obtained Nb · Al
The two-layer clad sheet 12 is formed into a sheet having a diameter of 6 mm and a length of 150 mm
Was wound around an Nb rod to obtain an Nb / Al composite sheet wound wire.

(3) Next, outer diameter φ28.5 mm, inner diameter φ2
A Cu-coated Nb tube was obtained by inserting a Nb tube having an outer diameter of 24.6 mm, an inner diameter of 22.3 mm, and a length of 150 mm into a Cu tube having a length of 5 mm and a length of 170 mm.

Next, the Nb / Al composite sheet wound wire 5 obtained in the above (2) was inserted into the Cu-coated Nb tube obtained here to obtain an Nb / Al composite sheet bus. .

(4) Next, both ends of the obtained Nb / Al composite sheet bus were sealed to obtain a monofilament billet.

(5) Next, the monofilament billet obtained in the above (4) was subjected to hydrostatic extrusion at room temperature to obtain a monofilament wire having a diameter of 12 mm.

(6) Next, the monofilament wire obtained in the above (5) was drawn with a hexagonal die, and the side length 2.7 was obtained.
A 7 mm hexagonal section monofilament wire was obtained. Then, the obtained hexagonal cross-section monofilament wire was straightened and straightened, cut into a length of 150 mm, further washed and dried.

(7) Next, a copper wire having a diameter of φ12 mm was prepared and drawn with a hexagonal die to obtain a hexagonal cross-section copper wire having a side length of 2.77 mm. Then, the hexagonal section copper wire obtained here was straightened, cut to a length of 150 mm, and further washed,
Dried.

(8) Next, the multifilament is obtained by arranging 48 hexagonal cross-section monofilament wires obtained in (6) around one hexagonal cross-section copper wire obtained in (7) above. I got

(9) Next, the outer diameter φ28.5 mm and the inner diameter φ2
A multifilament billet was obtained by inserting the multifilament obtained in the above (8) into a 3.4 mm, 170 mm long Cu tube.

(10) Next, the multifilament billet obtained in the above (9) was heated to 400 ° C. and then extruded with hydrostatic pressure to have an outer diameter of 12 mm.

(11) Next, the outer diameter φ1 obtained in the above (10)
A 2 mm multi-filament billet was drawn through a wire drawing machine to obtain a multi-filament wire having an outer diameter of 0.6 mm and a length of 260 m.

(12) Next, the multifilament wire obtained in (11) was subjected to a diffusion reaction at 800 ° C. to obtain an Nb ₃ Al-based superconducting wire of Example 2.

(13) The Nb ₃ Al-based superconducting wire of Example 2 thus obtained is as long as 260 m.
In addition, although not shown as data, it has a high critical magnetic field and can withstand use up to a high magnetic field, and furthermore, has exhibited excellent resistance to distortion.

In Examples 1 and 2, the Nb / Al composite sheet wound wire was obtained by winding the Nb / Al two-layer clad sheet 12 or the Nb / Al three-layer clad sheet 4 around the Nb rod. However, in the present invention, a Nb / Al composite sheet-wound filament can be obtained without an Nb rod,
And the same excellent effect can be obtained.

[0078]

According to the method for producing an Nb ₃ Al-based superconducting wire of the present invention, a long wire can be obtained, and the obtained wire has a high critical magnetic field and can withstand use up to a high magnetic field. In addition, it has excellent strain resistance and is industrially useful.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an Nb · Al three-layer clad sheet used in one embodiment of a method for producing an Nb ₃ Al-based superconducting wire of the present invention.

FIG. 2 is a cross-sectional explanatory view showing a situation in which an Nb / Al composite sheet wound wire is obtained by winding the Nb / Al three-layer clad sheet of FIG. 1 around an Nb rod.

FIG. 3 is a cross-sectional view of the Nb / Al composite sheet wound wire obtained in FIG. 2;

FIG. 4 is a cross-sectional view of an Nb / Al composite sheet bus corresponding to a first intermediate product obtained by one embodiment of the method for manufacturing an Nb ₃ Al-based superconducting wire of the present invention.

FIG. 5 is a perspective explanatory view of a multifilament corresponding to a second intermediate product obtained by one embodiment of the method for manufacturing an Nb ₃ Al-based superconducting wire of the present invention.

FIG. 6 is a longitudinal sectional view showing an Nb · Al double-layer clad sheet used in another embodiment of the method for producing an Nb ₃ Al-based superconducting wire of the present invention.

FIG. 7 is a cross-sectional explanatory view showing a state in which a Nb · Al laminated sheet wound body is produced by winding an Nb · Al laminated sheet around an outer periphery of an Nb rod in a conventional method for producing an Nb ₃ Al based superconducting wire. It is.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Nb sheet layer 2 Al sheet layer 3 Nb rod 4 Nb / Al three-layer clad sheet 5 Nb / Al composite sheet wrapped wire 6 Cu tube 7 Nb tube 8 Nb / Al composite sheet bus 9 Hexagonal section monofilament wire 10 Multi Coated Cu tube 11 Multifilament 12 Nb / Al double layer clad sheet

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Morio Kimura 3550 Kida Yomachi, Tsuchiura City, Ibaraki Prefecture Within Hitachi Cable, Ltd.System Materials Research Laboratories (72) Kazuhiko Nakagawa 3550 Kida Yomachi, Tsuchiura City, Ibaraki Prefecture Hitachi Cable Co., Ltd. Company System Materials Laboratory

Claims (5)

[Claims] 1. A Nb ₃ Al Nb sheet and the Al sheet and the Nb ₃ Al-based method of manufacturing a superconducting wire, which comprises using a Nb · Al joined and integrated composite sheet formed by integrally bonding as formation material. 2. As an Nb / Al bonded integrated composite sheet,
Nb sheet and the Al sheet and the method according to claim 1 Nb ₃ Al superconducting wire, wherein the use of those made by cladding the. 3. An Nb / Al bonded integrated composite sheet,
Nb sheet and the Al sheet and the method according to claim 1 Nb ₃ Al superconducting wire, wherein the use of those made by welding. 4. An Nb / Al bonded integrated composite sheet,
Nb sheet and the Al sheet and the method according to claim 1 Nb ₃ Al superconducting wire, wherein the use of those made by bonding with an adhesive. 5. An Nb / Al bonded integrated composite sheet,
5. The method according to claim 1, wherein the thickness of the Nb sheet layer and the thickness of the Al sheet layer are configured so that the atomic weight ratio of Nb / Al is 3.0 to 4.5 / 1. The method for producing an Nb ₃ Al-based superconducting wire according to the above.