Method for producing Nb3Sn superconducting wire, precursor for Nb3Sn superconducting wire, and Nb3Sn superconducting wire using same

Patent metadata

Field	Value
Publication number	US-11476017-B2
Application number	US-201816494378-A
Country	US
Kind code	B2
Filing date	Feb 26, 2018
Priority date	Apr 27, 2017
Publication date	Oct 18, 2022
Grant date	Oct 18, 2022

Abstract

In the production of an internal-tin-processed Nb3Sn superconducting wire, the present invention provides a Nb3Sn superconducting wire that is abundant in functionality, such as, the promotion of formation of a Nb3Sn layer, the mechanical strength of the superconducting filament (and an increase in interface resistance), the higher critical temperature (magnetic field), and the grain size reduction, and a method for producing it. A method for producing a Nb3Sn superconducting wire according to an embodiment of the present invention includes a step of providing a bar 10 that has a Sn insertion hole 12 provided in a central portion of the bar 10 and a plurality of Nb insertion holes 14 provided discretely along an outer peripheral surface of the Sn insertion hole 12, and that has an alloy composition being Cu-xZn-yM (x: 0.1 to 40 mass %, M=Ge, Ga, Mg, or Al, provided that, for Mg, x: 0 to 40 mass %), a step of mounting an alloy bar with an alloy composition of Sn-zQ (Q=Ti, Zr, or Hf) into the Sn insertion hole 12 and inserting Nb cores into the Nb insertion holes 14, a step of subjecting the bar 10 to diameter reduction processing to fabricate a Cu-xZn-yM/Nb/Sn-zQ composite multicore wire with a prescribed outer diameter, and a step of subjecting the composite multicore wire to Nb3Sn phase generation heat treatment.

First claim

The invention claimed is:

1. A method for producing a Nb 3 Sn superconducting wire comprising:
a step of providing a bar, wherein the bar has a Sn insertion hole provided in a central portion of the bar and a plurality of Nb insertion holes provided discretely along an outer peripheral surface of the Sn insertion hole, and wherein the bar has an alloy composition of Cu-xZn-yGa, wherein x=0.1 to 40 mass %, and y=10 to 21 mass %;
a step of mounting an alloy bar into the Sn insertion hole and inserting Nb cores into the Nb insertion holes, wherein the alloy bar has an alloy composition of Sn-zQ, wherein z=0.5 to 4 mass %, and Q=Ti, Zr, or Hf;
a step of subjecting the bar to diameter reduction processing to fabricate a Cu-xZn-yGa/Nb/Sn-zQ composite multicore wire; and
a step of subjecting the composite multicore wire to Nb 3 Sn phase generation heat treatment at 650° C. to 800° C.

2. The method for producing a Nb 3 Sn superconducting wire according to claim 1 , wherein, before the Nb 3 Sn phase generation heat treatment, the composite multicore wire is subjected to preliminary heating to promote mutual diffusion of Zn and Sn.

3. The method for producing a Nb 3 Sn superconducting wire according to claim 1 , wherein, in the step of mounting the alloy bar into the Sn insertion hole and inserting the Nb cores into the Nb insertion holes, the Nb cores are inserted in the Nb insertion holes to obtain a Cu-xZn-yGa/Nb complex, the Cu-xZn-yGa/Nb complex is subjected to process annealing, and then the alloy bar is mounted into the Sn insertion hole.

4. A precursor for a Nb 3 Sn superconducting wire comprising:
a bar, wherein the bar has a Sn insertion hole provided in a central portion of the bar and a plurality of Nb insertion holes provided discretely along an outer peripheral surface of the Sn insertion hole, and wherein the bar has an alloy composition of Cu-xZn-yGa, wherein x=0.1 to 40 mass %, and y=10 to 21 mass %;
an alloy bar portion mounted in the Sn insertion hole, wherein the alloy bar portion has an alloy composition of Sn-zQ, wherein z=0.5 to 4 mass %, and Q=Ti, Zr, or Hf; and
Nb core portions inserted in the Nb insertion holes.

5. The precursor for a Nb 3 Sn superconducting wire according to claim 4 , wherein, in the Nb core portions, one or more elements selected from the group consisting of Ti, Hf, Zr, and Ta are contained at 0 to 5 mass %.

6. The precursor for a Nb 3 Sn superconducting wire according to claim 4 , wherein a space factor of the Nb core portions inserted in the bar is 5 to 80%.

7. A Nb 3 Sn superconducting wire made from the precursor for a Nb 3 Sn superconducting wire according to claim 4 subjected to Nb 3 Sn phase generation heat treatment,
wherein, an Nb 3 Sn layer having a thickness of 0.1 to 500 μm is formed when Sn is diffused in a Nb core, and part or all of Q, which is Ti, Zr, or Hf, contained in the alloy bar portion is dissolved as solid solution, and
wherein, after Sn contained in the alloy bar portion is diffused in the Cu matrix of the bar, the wire has substantially no vacancies.

Assignees

• Nat Inst Materials Science

Inventors

• Banno Nobuya
• Tachikawa Kyoji

Classifications

• Y02E40/60

  Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment · CPC title

• C22C9/00

  Alloys based on copper · CPC title

• C22C13/00

  Alloys based on tin · CPC title

• C22C9/01 Primary

  with aluminium as the next major constituent · CPC title

• Y10T428/12819

  Group VB metal-base component · CPC title