Process for producing ultrafine multifilamentary Nb3(Al, Ge) or Nb3(Al, Si) superconducting wire

摘要

A process for producing an ultrafine multifilamentary superconducting Nb₃(Al,Ge) or Nb₃(Al,Si) wire capable of generating a high critical current density comprising: preparing a composite core material comprising an Al-(2 - 30)at.% Ge or Si alloy 1 µm or less in thickness uniformly incorporated into a Nb matrix at a volume ratio in a range of 1:2.5 to 1:3.5 fabricating a composite wire by embedding several tens to several millions of the resulting composite core materials in a cylindrical matrix material containing Nb; forming a A15-phase filament having a lower order in crystallinity inside the composite wire by a rapid heating and quenching treatment comprising rapidly heating the composite wire to a temperature of 1,700 °C or higher in 2 seconds, followed by continuously introducing it into a molten metal; coating the composite wire in the state above with copper (Cu) which functions as a superconductivity stabilizing material; and applying a post heat treatment in the temperature range of from 650 to 900 °C to the resulting product to recover the degree of crystallinity of the Nb₃ (Al,Ge) in the A15 compound.