JPS61264609A - Manufacture externally reinforced compound superconductor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method for manufacturing an externally reinforced compound superconducting wire, and more particularly to a method for manufacturing an externally reinforced compound superconducting wire with excellent quality by diffusion bonding.

[Prior art] Conventionally, superconducting wires such as NbzSn, V3G a, etc.
It has been put into practical use as a wire for generating high magnetic fields of T or higher.
Further, it is being developed as a wire rod to be used as a large-capacity conductor for large magnets such as those used in nuclear fusion reactors.

In the case of such large-capacity conductors, because a large electromagnetic force acts on the conductor, they are reinforced with oxygen-free copper, stainless steel, molybdenum, etc. whose strength is increased by cold working to improve stress resistance. .

In addition, superconducting multicore wires based on compounds such as Nb*Sn are inherently brittle, so in small magnets, wires that have not been heat-treated to produce compounds such as Nb3Sn are used to build magnets. After winding, heat treatment is performed to generate a compound (Wi
and React method).

On the other hand, in consideration of practicality, it is difficult to adopt the Wind and React method described above for large magnets, and therefore magnet wires are wound using conductors that have been heat-treated to generate compounds (React method). and wind method).

In the case of this React and Wind method, there are two types: internal reinforcement method and external reinforcement method.The conductor structure that is generally put into practical use by the external reinforcement method has a cross-sectional shape as shown in Figure 1. Many have a gate-shaped copper-embedded conductor structure, and the manufacturing method for this structure is generally to add superconducting multifilamentary wires that have been heat-treated to form a compound in cold-worked gate-shaped oxygen-free copper material (four parts). Long materials are manufactured by joining them by soldering.

The gate-shaped oxygen-free copper in this structure is required to have high strength and high electrical conductivity.

When manufacturing such a gate-shaped copper-embedded conductor using a compound-based multicore wire, the wire rod, which has been heat-treated to form a compound, is usually buried in the recess of the gate-shaped copper strip and soldered at the same time. ing. During this soldering, it is necessary to solder the gate-shaped copper strip at as low a temperature as possible and in a short time to avoid softening.

Furthermore, the composite multi-filament wire material produced by heat treatment is extremely brittle, making it difficult to work with when embedding it in gate-shaped copper strips. Specifically, the wire material is subject to a strain of approximately 0.5% or more. It is known that the superconducting properties of the wire will deteriorate over time. Therefore, when embedding and soldering the wire, it is necessary to avoid applying strain of 0.5% or more to the wire.

Furthermore, during soldering, air bubbles often remain in the solder layer between the gate-shaped copper strip and the superconducting multifilamentary wire, resulting in insufficient cooling of the wire and impairing the superconducting properties.

[Problems to be Solved by the Invention] As explained above, the present invention solves various problems in embedding and soldering of gate-shaped copper strips and superconducting multicore wires in the prior art, As a result of repeated research and consideration by the present inventor, we have found that by using copper in which A1□03 is dispersed as the external reinforcing material, and by using non-diffusion heat-treated superconducting multifilamentary wire, it has been found that the embedding and soldering We have developed a method for manufacturing externally reinforced compound superconducting wires that does not cause deterioration of superconducting properties due to corrosion.

[Means for Solving the Problems 1] The method for manufacturing an externally reinforced compound superconducting wire according to the present invention is characterized by using A1□03 dispersion-strengthened copper as an external reinforcing material, and combining this with non-diffused heat-treated superconducting wire. The purpose of this method is to integrate the composite core wire into a composite and then perform a diffusion heat treatment.

The method for manufacturing an externally reinforced compound superconducting wire according to the present invention (hereinafter sometimes simply referred to as the method according to the present invention) will be described in detail below.

The Al2O3 dispersion-strengthened copper used in the method of the present invention has about 0.1 to 5 wt% of A I 203 dispersed in the shell, and the copper powder and A! 20:+
The copper powder is manufactured by a powder metallurgy method, the copper powder is complex-treated to form an Al2O3 film on the surface of the copper powder, or the copper powder is manufactured by a complex method in which an Al2O3 film is generated on the surface of the copper powder, or the internal oxidation method is applied to Cu-A1-based ingot material. Manufacture.

As shown in FIG. 2, this Al2O and dispersion-strengthened copper exhibits little decrease in strength even when subjected to heat treatment at high temperatures. This is clear when compared with oxygen-free copper, which is also shown in FIG. Further, as shown in FIG. 3, the electrical conductivity remains approximately the same as that at room temperature even after high-temperature heat treatment.

For this reason, A1203 dispersion-strengthened copper is an optimal material as a stabilizing material and reinforcing material for compound superconducting wires, NbTi alloy superconducting wires, and the like.

In the method according to the invention, the composite integration comprises A1201
Both the dispersion-strengthened copper and the non-diffusion heat-treated superconducting composite multifilament wire are assembled and integrated by brazing or by reducing the area by plastic working such as cold-open drawing or rolling of about 30% or less.

In addition, in the method according to the present invention, the diffusion heat treatment differs depending on the compound to be produced, but Nb3Sn and V3
In the case of Ga, etc., it is recommended to carry out the reaction at a temperature of 500 to 900'C.

A method for manufacturing an externally reinforced compound superconducting wire according to the present invention will be explained.

(1) Wire drawing processing of compound superconducting core wire.

(2) Processing of gate-shaped A1 20-dispersed copper strip.

(3) Gate type A 1203 Assembled by embedding multifilamentary compound superconducting multifilamentary wires in an undiffused heat-treated state in the four parts of dispersed copper,
Perform brazing or surface reduction adhesion processing.

(4) This structure is subjected to diffusion heat treatment to generate a compound.

Since the method according to the present invention can produce an externally reinforced superconducting wire through such steps, there is no need to perform diffusion heat treatment after drawing a compound superconducting multifilamentary wire as in the conventional method, and there is no need for diffusion heat treatment during assembly. There is no need to be very careful in handling the core wire, and there is no problem of deterioration of superconducting properties.

In addition, in the method according to the present invention, since the superconducting multifilamentary wire is assembled in an unreacted, undiffused heat-treated state where no compounds are generated, there is no risk of deterioration of the superconducting properties, and the unreacted superconducting multifilamentary wire is not heated by brazing or cold working. Since the superconducting multifilamentary wire in the diffusion heat-treated state and the gate-shaped ALO3 dispersion-strengthened copper are in close contact with each other, it is possible to produce an externally reinforced compound superconducting wire of extremely excellent quality by diffusion bonding by heat treatment.

[Example 1] An example of the method for manufacturing an externally reinforced compound superconducting wire according to the present invention will be described.

Example As shown in Figure 1, Nb with an outer diameter of 1.5 x 4.0 mm2
3Sn superconducting multicore wire 1 (10,285 cores, bro
nze/N b= 2, 8, Cu/noncu=
0,33) and Wi=4.2mm, ti=1.5m
n+, W = 10.0mm, t”4.5mmn+ portal type Al2O, after assembling with dispersion strengthened copper 2, perform surface reduction processing and embed portal type copper with 4.15 x 9.2mm opening. It was used as a conductor.

This conductor was heat treated in 660'CX300HrAr gas to produce a product.

AI as a reinforcing material used here. The amount of A1□03111t% in the 03 dispersion-strengthened shell was 0.8u+t%, and the powder produced by the complex treatment method was compressed and filled into an oxygen-free copper case, sealed in a vacuum, and then heated at a temperature of 800'C. The hot isostatically extruded material was drawn into a gate-shaped strip.

The tensile strength of the A I 203 dispersion strengthened copper part after heat treatment is 3
2kg/mm2.The specific resistance at 4.2K is 1.05X
The residual resistance at IO”ΩcIII, IIT is 15°9
It was μΩm.

The superconducting composite multifilamentary wire and the gate-shaped A l 20 ] dispersion-strengthened copper reinforcing material were completely diffusion-bonded.

Further, the assembled conductor was subjected to heat treatment at 700° C. for 100 hours to generate Nb and Sn.

The tensile strength of Al2O3 dispersion strengthened copper after heat treatment is 30kg
/mm2.The specific resistance at 4.2K is 8.9×10-8
The residual resistance at Ωcm and 11T was 11.5μ52m.

[Effect of the invention 1] As explained above, since the method for manufacturing an externally reinforced compound superconducting wire according to the present invention has the above-mentioned configuration, the superconducting properties can be prevented from deteriorating due to handling or brazing of the superconducting multifilamentary wire. Furthermore, the superconducting multifilamentary wire and the A I 203 dispersion-strengthened copper are integrated into a composite structure, which has the effect of producing products with excellent strength and electrical conductivity.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the method for manufacturing an externally reinforced compound superconducting wire according to the present invention, and FIGS. 2 and 3 are illustrations of A as a reinforcing material in the method for manufacturing an externally reinforced compound superconducting wire according to the present invention.
FIG. 1 is a diagram showing the annealing temperature, tensile strength, and electrical conductivity of 1□03 dispersion-strengthened copper.

Claims (1)

[Claims] A method for producing an externally reinforced compound superconducting wire, which comprises using Al_2O_3 dispersion-strengthened copper as an external reinforcing material, integrating the same with a non-diffusion heat-treated superconducting composite multifilamentary wire, and then performing diffusion heat treatment.