Multifilament superconductors

Claim 1

A composite superconductor which comprises: multifilaments of an alloy selected from the group consisting of a vanadium-gallium alloy with a gallium content from 0.4 at. % to 12.5 at. %, a niobium-tin alloy with a tin content from 0.1 to 12 at. % and a vanadium-silicon alloy with a silicon content of 0.5-10 at. %; a matrix sheath of an alloy selected from the group consisting of a copper-gallium alloy with a gallium content from about 0.4 to about 22 at. %, a copper-tin alloy with a tin content from about 1 to about 11 at. %, a copper-silicon alloy with a silicon content from about 0.5 to 14 at. %, so that the matrix alloy has the same metal solute as the core alloy; and an intermediate layer of an A-15 compound produced by a solid state reaction between said core rod and said matrix sheath.

Claim 7

A method for fabricating a composite superconductor which comprises: homogenization-annealing filament rods of an alloy selected from the class consisting of a vanadium-gallium (V--Ga) alloy with a gallium content from 0.4 at. % to 12.5 at. %, a niobium-tin (Nb--Sn) alloy with a tin content from 0.1 at. % to 12.0 at. %, and a vanadium-silicon (V--Si) alloy with a silicon content from 0.5 at. % to 10 at. % and a matrix sheath rod of an alloy selected from the class consisting of a copper-gallium (Cu--Ga) alloy with a gallium content from 0.4 at. % to 22 at. %, a copper-tin (Cu-Sn) alloy with a tin content from 1 at. % to 11 at. % and a copper-silicon (Cu-Si) alloy with a silicon content from 0.5 at. % to 14 at. %, reducing said rods by mechanical technique, boring said matrix rod to form a multicavity matrix sheath, forming an end plug having axial grooves about its periphery, annealing said filament rods from about 2 to about 16 hours at a temperature from about 750° C to about 850° C if V--Ga or V--Si is selected, and at a temperature from about 1050° C to about 1150° C if Nb--Sn is selected, annealing said matrix sheath at a temperature from about 500° to about 800° C for at least about 1 hour, etching said filament rods with an etching solution, placing said filament rods within said matrix sheath whereby a binary multicavity composite of an alloy combination selected from the class consisting of (V--Ga)-(Cu--Ga), (V--Si)-(Cu--Si), and (Nb--Sn)-(Cu--Sn) is formed having an annular air space between said matrix sheath and said filament rods, placing said end plug into said matrix sheath, subjecting said composite to a vacuum, sealing said composite while under a vacuum, reducing the diameter of said composite by 20%, annealing said composite at a temperature from about 500° to about 525° C for at least 1 hour, reducing the diameter of said composite by 20%, annealing said composite at a temperature from about 500° to about 525° C for at least one hour, reducing the diameter of said composite by 20%, annealing said composite at a temperature from about 550° to about 575° C for at least 1 hour, repeating the previous reduction steps until the desired diameter of the composite is obtained, and heating said composite at about 475° to about 700° C if said composite is V--Ga, Cu--Ga or V--Si, Cu--Si, whereas if said composite is Nb--Sn, Cu--Sn, the temperature is to be about 525° to about 850° C.

Claim 8

A method for fabricating a composite superconductor which comprises: homogenization-annealing filament rods of an alloy selected from the class consisting of a vanadium-gallium (V--Ga) alloy with a gallium content from 0.4 at. % to 12.5 at. %, a niobium-tin (Nb--Sn) alloy with a tin content from 0.1 at. % to 12.0 at. %, and a vanadium-silicon (V--Si) alloy with a silicon content from 0.5 at. % to 10 at. % and a matrix sheath rod of an alloy selected from the class consisting of a copper-gallium (Cu--Ga) alloy with a gallium content from 0.4 at. % to 22 at. %, a copper-tin (Cu-Sn) alloy with a tin content from 1 at. % to 11 at. % and a copper-silicon (Cu-Si) alloy with a silicon content from 0.5 at. % to 14 at. %, reducing said rods by mechanical technique, boring said matrix rod to form a multicavity matrix sheath, forming an end plug having axial grooves about its periphery, annealing said filament rods from about 2 to about 16 hours at a temperature from about 750° C to about 850° C if V--Ga or V--Si is selected, and at a temperature from about 1050° C to about 1150° C if Nb--Sn is selected, annealing said matrix sheath at a temperature from about 500° to about 800° C for at least about 1 hour, etching said filament rods with an etching solution, placing said filament rods within said matrix sheath whereby a binary multicavity composite of an alloy combination selected from the class consisting of (V--Ga)-(Cu--Ga), (V--Si)-(Cu--Si), and (Nb--Sn)-(Cu--Sn) is formed having an annular air space between said matrix sheath and said filament rods, placing said end plug into said matrix sheath, subjecting said composite to a vacuum, sealing said composite while under a vacuum, reducing the diameter of said composite by 20%, annealing said composite at a temperature from about 500° to about 525° C for at least 1 hour, reducing the diameter of said composite by 20%, annealing said composite at a temperature from about 500° to about 525° C for at least one hour, reducing the diameter of said composite by 20%, annealing said composite at a temperature from about 550° to about 575° C for at least 1 hour, repeating the previous reduction steps until the desired diameter of the composite is obtained, and heating said composite at about 475° to about 700° C if said composite is V--Ga, Cu--Ga or V--Si, Cu--Si, whereas if said composite is Nb--Sn, Cu--Sn, the temperature is to be about 525° to about 850° C.