JPH0471115A - Manufacture of multiple-conductor superconducting wire of nb3al - Google Patents

Abstract

PURPOSE:To enable heat treatment at a high temperature to thereby increase generating volume of Nb3Al and to improve characteristics by dispositioning high fusing point Ta around sheath materials and each filaments. CONSTITUTION:A Nb tube and an Al rod are accommodated inside of a Ta tube and a Cu-Ni alloy tube is plated outside of the Ta tube to form a composite body A. The composite body A is formed in hexagonal cross section shape, and the an outside Cu-Ni alloy tube is removed, to manufacture a composite wire B in the hexagonal cross section shape. The composite wire B is accommodated in the Nb tube and the Cu-Ni alloy tube is placed outside of the Nb tube to form a composite body C. The composite body C is formed in the hexagonal cross section shape, and then an outside Cu-Ni alloy tube is removed, to manufacture a composite wire D in the hexagonal cross section shape. The composite wire D is accommodated in the Nb tube, and the Ta and Cu-Ni alloy tube are placed outside of the Nb tube to form a composite body E. The composite body E is formed in the hexagonal cross section shape, and then an outside Cu-Ni alloy tube is removed, to manufacture a composite wire F. Electronic beams are radiated to the composite wire F to manufacture a Nb3Al multiple-conductor superconducting wire.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a superconducting wire, and more particularly to a method for manufacturing a Nb3 Al multicore superconducting wire that has excellent properties due to heat treatment at high temperatures.

[Prior art] Compound-based superconducting materials have superior superconducting properties compared to alloy-based superconducting materials, and it is known that Nb and Al in particular have a high upper critical magnetic field and excellent mechanical properties. However, there are problems in that the generation temperature is high and the heat treatment takes a long time.

A jelly roll method and a powder method are known as methods for improving such heat treatment conditions.

In the above method, the heat treatment conditions are improved by finely dispersing Nb in Al and allowing grain boundary diffusion to proceed dominantly, but the formation of a stable compound phase at high temperatures of 1700°C or higher There is a problem that the amount is small and sufficient properties as a wire cannot be obtained.

For this reason, various methods of heat treatment at high temperatures have been studied in the past [Problem to be solved by the invention] However, heat treatment at high temperatures, such as high energy density irradiation by laser beam irradiation, electron beam irradiation, etc., has not been applied to wire rods. When this process is applied, the Nb and Cu alloys that are commonly used as sheath materials for wire rods melt and the wire rods are significantly deformed, making it almost impossible to put them into practical use. It is.

The present invention was made to solve the above-mentioned problems, and by arranging high-melting-point Ta on the sheath material and the outer periphery of each filament, heat treatment at high temperatures is made possible.

[Means for Solving the Problems] In order to solve the above problems, Nb, Al of the present invention
The method for manufacturing multicore superconducting wires consists of (a) arranging a large number of Ta tubes in a matrix whose outer layer is coated with Ta;
a step of accommodating Nb or a Nb-based alloy and Al or an Al-based alloy inside a tube to form a composite; (b) a step of manufacturing a wire rod by subjecting the composite to area-reducing processing; and (c)
The wire is irradiated with a high energy density beam or heat-treated at a temperature higher than the melting point of Nb.
Alternatively, a Nb-based alloy is reacted with Al or an Al-based alloy.

The present invention can be applied to a powder method, a tube method, a jelly roll method, etc., as well as a clad chip method and an infiltration method.

In the above powder method, Nb or Nb is added inside the Ta tube.
A base alloy and a mixed powder of Al or Al-based alloy are accommodated, and in the tube method, Nb or Nb
An Al or Al-based alloy rod coated with a base alloy is accommodated.

On the other hand, in the jelly roll method, an Nb sheet and an Al sheet with many slits are wound, and then the Ta
It is housed inside a tube, and in any case, it is made into a wire rod by surface reduction processing such as hydrostatic extrusion processing, swaging processing, and wire drawing processing.

As the beam irradiated to the wire, a high energy density beam such as an electron beam or a laser beam is used.

[Function] In the method of the present invention, Nb producing a superconducting compound
Or the Nb-based alloy and Al or the Al-based alloy are Nb
T with a high melting point (2850°C) approximately 900°C higher than the melting point of
Since Nb3Al is coated with a and Ta is also arranged on the outer layer, it is possible to perform heat treatment at a higher temperature than conventional methods, that is, irradiation with a high energy density beam or heat treatment at a temperature higher than the melting point of Nb. Since the amount of produced increases, characteristics such as critical current density (Jc) can be improved.

[Example] An embodiment of the present invention will be described below.

An outer diameter of 3 mm is inside a Ta tube with an outer diameter of 411+6 and an inner diameter of 3.1 mm.

A Nb tube with an inner diameter of 2.11mm and an Al0 tube with an outer diameter of 2+ms are housed, and a Cu-N1 alloy tube with an outer diameter of 5.5o+a and an inner diameter of 4.1cm is placed outside this Ta tube to form a composite (A).
was formed. Next, this composite (A) was subjected to area reduction processing and formed into a hexagonal cross section, and then the outer Cu-Ni alloy tube was removed with nitric acid to obtain a composite wire (with a hexagonal cross section with a distance between parallel surfaces of 1.0+gm B) was produced.

The 931 pieces of the above composite wire (B) are housed in a Nb tube with an outer diameter of 38 mm and an inner diameter of 33 + g + t with their sides abutted, and the outer diameter of the wire is 4511% and the inner diameter H1,1 is placed outside the Nb tube.
A composite (C) was formed by placing 11 m of Cu-N1 alloy tubes.

This composite (C) was subjected to hydrostatic extrusion processing and wire drawing processing to form a hexagonal cross section, and then the outer Cu-Ni alloy tube was removed with nitric acid so that the distance between parallel surfaces was 1. A composite wire (D) with a hexagonal cross section of Oev was manufactured. 9 of the above compound line (D)
31 pieces are brought into contact with their sides and have an outer diameter of 381 mm and an inner diameter of 33 m5.
It is housed in a Nb tube with an outer diameter of 40111%, an inner diameter of 38.1 mm on the outside of this Nb tube, and a Ta tube with an outer diameter of 45 mm.
A composite (E) was formed by arranging Cu-Ni alloy tubes with an internal diameter of 40.1*+g. This composite (E) was subjected to hydrostatic extrusion and wire drawing to form a hexagonal cross section, and then the outer Cu-1 alloy tube was removed with nitric acid to give an outer diameter of 1.0.
■ A composite wire (F) of φ was manufactured.

The above composite wire (F) is subjected to electron beam irradiation to produce Nb3
An Al multicore superconducting wire was manufactured.

The electron beam irradiation conditions were: Accelerating voltage: 80 kV Irradiation current: 7 mA Beam diameter: 2.7 - Irradiation speed - 1500 ms/sin The resulting critical current of the multicore superconducting wire Density is 5500 OA/cd at 12T (Tesla), 1
It was 47000A/c- at 7T.

[Effects of the Invention] As described above, according to the present invention, by disposing high melting point Ta on the sheath material and the outer periphery of each filament,
Since heat treatment at a high temperature is possible, the amount of Nb3^1 produced can be increased, and as a result, a multicore superconducting wire with excellent characteristics can be manufactured.

Claims (4)

[Claims] (1) (a) A large number of Ta tubes are arranged in a matrix whose outer layer is coated with Ta, and inside these Ta tubes there is Nb or N.
a step of accommodating a b-based alloy and Al or an Al-based alloy to form a composite; (b) a step of manufacturing a wire by subjecting the composite to area reduction processing; and (c) providing the wire with a high energy density. A method for manufacturing a Nb_3Al multicore superconducting wire, characterized in that the Nb or Nb-based alloy and Al or Al-based alloy are caused to react at high temperature by irradiating a beam of. (2) Nb or Nb-based alloy and Al or Al-based alloy housed inside the Ta tube are Al or Al-based alloy rods coated with Nb or Nb-based alloy.
The method for manufacturing the Nb_3Al multicore superconducting wire described above. (3) The Nb_3Al multicore superconductor according to claim 1, wherein the Nb or Nb-based alloy and Al or Al-based alloy housed inside the Ta tube are mixed powders of Nb or Nb-based alloy powder and Al or Al-based alloy powder. Method of manufacturing wire. (4) (a) A large number of Ta tubes are arranged in a matrix whose outer layer is coated with Ta, and inside the Ta tubes there is Nb or N.
a step of accommodating a b-based alloy and Al or an Al-based alloy to form a composite; (b) a step of producing a wire rod by subjecting the composite to an area reduction process; and (c) a step of applying the melting point of Nb to the wire rod. A method for producing a Nb_3Al multicore superconducting wire, characterized in that the Nb or Nb-based alloy is reacted with Al or the Al-based alloy by heat treatment at a temperature above.