JPS6173849A - Superconductive cu alloy - Google Patents

Abstract

PURPOSE:To obtain the titled alloy having superior workability, mechanical characteristics and improved electric conductivity by uniformly dispersing fine metallic particles having the 2nd phase in the matrix phase of a Cu alloy contg. a specified amount of Pb, Bi, Tl, Li or Fe. CONSTITUTION:This superconductive Cu alloy ha a structure contg. fine metallic particles having the 2nd phase dispersed uniformly in the matrix phase of a Cu alloy consisting of 1-10atomic% one or more among Pb, Si, Tl, Li and Fe and the balance essentially Cu. The superconductive Cu alloy can be manufactured by melting an alloy having said composition by heating and by solidifying the molten alloy by rapid cooling. The superconductivity is improved by said structure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to Cupu gold having excellent superconducting properties and having a structure in which fine second phase metal particles are uniformly dispersed in the matrix.

Conventionally, superconducting materials include Ntl:+Sn, V, l
Ga+NbTt alloys and the like are well known. but,
However, these superconducting compounds still have some practical and manufacturing problems. The problems include, for example, the difficulty in forming wire rods.

In other words, various uses utilizing superconducting properties.

For example, at present, superconducting materials in the form of wire rods are desired for use in superconducting coils and equipment parts, and materials that are easy to mold, such as 9M construction and processing, and have excellent superconducting properties are preferred.

Previously, in an attempt to achieve the above objective, there were reports on materials that utilized the workability of the base material and tried to improve superconducting properties through the proximity effect, such as CH1 J, R & E, R; Fish (ch, J, R
aub and E, Raub; Z, Ph1s
ik) 186 (1965), 310. In this report, since the Tc (superconducting transition temperature) of the cast material is low, it is further quenched and aged, and the Tc (superconducting transition temperature) is improved by quenching.
It shows the relationship between c and pb particles. Also, Cu-N
Similar research has been conducted on b-alloys and the like. However, these exhibit good Tc only after being subjected to optimal heat treatment conditions, and furthermore, PB and Nb particles precipitate at the grain boundaries due to heat treatment, resulting in significant deterioration of mechanical properties. In other words, these reports attempted to obtain materials with excellent workability and superconducting properties from the good workability of the base material and the proximity effect of PB particles. Although the processability is excellent, the superconducting properties are low, and if the superconducting properties are further quenched and aged, the superconducting properties improve, but the processability decreases significantly, so the intended purpose cannot be achieved at all. and Tc is 1
-2 was of no use at all.

Furthermore, in general superconducting materials, when the superconducting state is broken, a large current flows, which causes abnormal heat generation, boiling the surrounding liquid Lie gas, and causing an explosion due to the vaporized He gas. For these reasons, it is desirable that the conductivity of the superconducting material be as high as possible.

On the other hand, there was a presentation that investigated the superconducting properties of the alloy material obtained by rapidly solidifying a second-phase metal particle-dispersed former-PB alloy using a liquid quenching method [Japan Institute of Metals: Shunho Conference General Overview (April 1984) P2S5).

According to this report, it was possible to uniformly disperse fine PB particles with a particle size of about 40 nm in the matrix, and the superconducting properties were also improved. However, since it is an Al-based alloy, 'J
=N rate was not fully satisfactory.

The present inventors conducted intensive studies with the aim of providing an alloy that easily leaks current even when the superconducting state is broken, that is, has high electrical conductivity.
When a u-based alloy is rapidly solidified.

The above objects have been achieved, and an alloy having a structure in which fine second phase metal particles are uniformly dispersed can be obtained.

The present invention was completed based on the discovery that the obtained alloy was a Cu-based alloy with excellent superconducting properties.

In other words, the two present inventions are Pb, Bi, Tl, l, i,
A small number selected from the group consisting of Fe (each type is 1 to 1
There is a Cu-based superconducting alloy having a U weave in which the content is 0 atomic %, the remainder is substantially Cu, and fine second phase metal particles are uniformly dispersed in the matrix.

To explain the alloy of the present invention, Pb, Bi,
T.I.

It is necessary that at least one selected from the group consisting of L+ and Fe is present in an amount of 1 to 10 atom %, and particularly preferably 2 to 5 atom %. Pb, Bi, Tl,
Li.

At least one selected from the group consisting of Fe is 1 atomic %
In the case of no groove, Tc is very low, less than 1.5.

In addition, if it exceeds 10 atomic %, the second phase metal particles in the matrix of the resulting alloy will not be uniformly dispersed.
c becomes very variable, and mechanical strength also decreases.

In addition, one or more elements selected from the group consisting of Ah, Si, and Sn may be added to the alloy of the present invention in an amount of 4 to 17 atomic % (
When Sn is added (3 to 15 atomic %), preferably 5 to 10 atomic %, the uniformity of the particle size and the dispersion state of the second metal particles remain good, and the matrix is strengthened and the mechanical properties are improved. The effect of improving wear resistance and wear resistance can be seen. especially,
Superconducting alloys have excellent mechanical properties 4.For example, they provide high strength, and when used as lead wires or sensors, tension is applied, but this process has the advantage of being very easy to perform without any problems. It can also be used as a structural material.

In order to produce the alloy of the present invention, the alloy composition described above may be heated and melted in an atmosphere or in a vacuum, and then cooled and solidified. Although there are various methods for rapid cooling, for example, a single roll method, a twin roll method known as a liquid cooling method, a spinning method in a rotating liquid, and the like are particularly effective. In the single roll method and the twin roll method, a thin ribbon material can be produced, whereas in the 9-turn submerged spinning method, a thin wire material can be easily produced continuously and at low cost.

The alloy of the present invention has no segregation in the molten state.

Although the alloy is completely alloyed, by rapidly solidifying it at an appropriate rate, the grain size of
It becomes an m-weave containing very fine second phase metal particles of about n size and uniformly dispersed at intervals of about 1 to 1100 n.

To give a specific example, the second phase metal particle dispersed alloy of the present invention having an alloy composition of 94Cu-6Pb has Pb particles having a particle size of about 20 to 40 nm and an almost perfect spherical shape in a Cu matrix. The particles are dispersed at intervals of about 50 to 80 nm, which is finer than in conventional particle-dispersed alloys.

It has excellent uniformity of dispersion.

Since the Cu-based alloy of the present invention has the structure shown in h, the superconducting properties are improved, especially for Pb, Bi, and TI.

Tc can be controlled freely by changing Li and Fel, and it has good workability and can be cold rolled and drawn, so it can be used as a wiring material for devices used under liquid helium, and for various industrial materials such as liquid level meters. It is very useful as In particular, liquid helium level meters are
A material with a Tc of around 4.2 is used as the reher sensor, and the transition from superconductivity to normal conduction must be sharp, and the alloy of the present invention is particularly excellent in this respect.

The present invention will be specifically explained below using examples.

Examples 1-16. Comparative Examples 1 to 18 Cu-based alloys having various compositions shown in Table 1 were melted in an argon gas atmosphere, and the argon injection pressure was 4.0 kg/cm2.
+ 3 from a ruby spinning nozzle with a hole diameter of 0.12 nuwΦ
A thin wire material having a circular cross section with an average diameter of 0.1 mmΦ is produced by ejecting it into a rotating cooling liquid with a temperature of 4°C and a depth of 2 cm formed in a cylindrical drum with an inner diameter of 500 mmΦ rotating at 2 rpm and rapidly solidifying it. Obtained.

The structure of these thin wire materials was observed using a transmission electron microscope. 1. Mechanical properties were measured using an Instron type tensile tester at room temperature.

As for the superconducting transition temperature (Tc), the sample is mounted inside a cryoskunoto, filled with dilute helium gas, and immersed in liquid helium.1The electrical resistance of the sample is measured using the usual four-terminal method. did.

Also, the limit reduction rate that can be drawn to indicate processed products.

The rapidly solidified wire is continuously cold-drawn using a normal diamond die at a rolling reduction rate of 5% for each die, and the limit rolling reduction rate that can be drawn is calculated from the wire diameter where the break occurs.
% or more was considered to have excellent workability.

Here, the rolling reduction rate is R58, (χ) = (1~-)X1
00R, A, : Reduction ratio So; Cross-sectional area of rapidly solidified wire before drawing (mm”) S;
It refers to the cross-sectional area reduction rate of the wire rod expressed in the cross-sectional area (mm'') of the drawn wire rod after drawing.

Also, for comparison, ch, J, and R described in the prior art
Similar to the experiment conducted by Raub et al., a Cu-2pb alloy was obtained by a normal casting method, and the material was solid-phase quenched in water at 800°C (Comparative Example-1), Table 1- 2 Table-1-3 As is clear from Table 1, Example 1.2.5゜7, 8
．． 9.10.11.12.13. 14.15.16
Comparative Example 3. is a superconducting material with good workability in which secondary metal particles are uniformly dispersed in Cu. 8.10.12
゜14, 17 are Pb, Bi, Tl, Fe, Li
i is small, and Tc does not appear at 1.5 (the following measurements cannot be made at 1.5 on the measuring equipment) L-over-l intersection example 4. 9.
II, 13.15.18 is Pb, 8i.

The amounts of Tl, Fe, and Li were too large, making it difficult for the second phase metal particles to be uniformly dispersed, making the material impractical.

Furthermore, in Examples 3 to 5, the addition of Si, AI, and Sn improved the mechanical properties without deteriorating the superconducting properties. However, in Comparative Examples 5 to
In No. 7.16, Si, AI, and Sn exceeded the appropriate amounts, so the parent phase did not become a Cu solid solution, and a compound phase appeared, reducing workability.

In addition, although Comparative Examples 1 and 2 have the same composition as the present invention,
The number of second phase metal particles was poor, and they were particularly precipitated at grain boundaries, and the workability and Tc were also low, making it completely useless as a superconducting material.

Claims (1)

[Claims] (1) At least one selected from the group consisting of Pb, Bi, Tl, Li, and Fe is present in an amount of 1 to 10 atomic %, and the remainder is substantially Cu, and a fine second phase metal is present in the matrix. A Cu-based superconducting alloy having a structure in which particles are uniformly dispersed.