WO1986001677A2 - Multi-filament superconductor wire production - Google Patents
Multi-filament superconductor wire productionInfo
- Publication number
- WO1986001677A2 WO1986001677A2 PCT/US1985/000792 US8500792W WO8601677A2 WO 1986001677 A2 WO1986001677 A2 WO 1986001677A2 US 8500792 W US8500792 W US 8500792W WO 8601677 A2 WO8601677 A2 WO 8601677A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- wires
- metal
- accordance
- composite
- superconductor
- Prior art date
Links
- 239000002887 superconductor Substances 0.000 title claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 229910052751 metal Inorganic materials 0.000 claims abstract description 49
- 239000002184 metal Substances 0.000 claims abstract description 48
- 239000012467 final product Substances 0.000 claims abstract 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 19
- 239000010949 copper Substances 0.000 claims description 19
- 229910052802 copper Inorganic materials 0.000 claims description 19
- 239000004744 fabric Substances 0.000 claims description 19
- 238000000034 method Methods 0.000 claims description 19
- 239000002131 composite material Substances 0.000 claims description 15
- 239000011159 matrix material Substances 0.000 claims description 14
- 239000000047 product Substances 0.000 claims description 11
- 229910045601 alloy Inorganic materials 0.000 claims description 10
- 239000000956 alloy Substances 0.000 claims description 10
- 150000001875 compounds Chemical group 0.000 claims description 8
- 239000011888 foil Substances 0.000 claims description 8
- REDXJYDRNCIFBQ-UHFFFAOYSA-N aluminium(3+) Chemical class [Al+3] REDXJYDRNCIFBQ-UHFFFAOYSA-N 0.000 claims description 7
- 239000003870 refractory metal Substances 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 6
- -1 niobium-titanium alloy Chemical class 0.000 claims description 6
- 238000005096 rolling process Methods 0.000 claims description 6
- 229910000999 vanadium-gallium Inorganic materials 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 229910001275 Niobium-titanium Inorganic materials 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims description 3
- 235000012438 extruded product Nutrition 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims description 2
- 239000000470 constituent Substances 0.000 claims 1
- 238000003780 insertion Methods 0.000 claims 1
- 239000002905 metal composite material Substances 0.000 claims 1
- 150000002739 metals Chemical class 0.000 claims 1
- 238000009941 weaving Methods 0.000 claims 1
- 238000001125 extrusion Methods 0.000 abstract description 17
- 238000000926 separation method Methods 0.000 abstract 2
- 239000010955 niobium Substances 0.000 description 13
- 229910052758 niobium Inorganic materials 0.000 description 12
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 10
- 229910052733 gallium Inorganic materials 0.000 description 6
- 229910000906 Bronze Inorganic materials 0.000 description 5
- 239000010974 bronze Substances 0.000 description 5
- 229910052720 vanadium Inorganic materials 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 229910052718 tin Inorganic materials 0.000 description 4
- ATJFFYVFTNAWJD-UHFFFAOYSA-N tin hydride Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 4
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 3
- 229910020012 Nb—Ti Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 3
- 229910052715 tantalum Inorganic materials 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium(0) Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 229910000951 Aluminide Inorganic materials 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 235000015110 jellies Nutrition 0.000 description 2
- 239000008274 jelly Substances 0.000 description 2
- OZAIFHULBGXAKX-UHFFFAOYSA-N precursor Substances N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 229910001134 stannide Inorganic materials 0.000 description 2
- 206010067484 Adverse reaction Diseases 0.000 description 1
- 210000001503 Joints Anatomy 0.000 description 1
- 229910001257 Nb alloy Inorganic materials 0.000 description 1
- 229910001069 Ti alloy Inorganic materials 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 230000002596 correlated Effects 0.000 description 1
- 230000000875 corresponding Effects 0.000 description 1
- 230000002939 deleterious Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910000657 niobium-tin Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000000737 periodic Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 239000002759 woven fabric Substances 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Definitions
- the present invention relates to production of multifilament superconductive wires of the class comprising 5,000 - 35,000 of such filaments in a wire.
- Another prior art technique is the use of expanded Nb-Ti mesh in a "jelly roll" type billet. While this technique simplifies the manufacture of fine filaments, it has the drawback that there are periodic junctions between filaments which may limit use to d.c. coils. An additional drawback is that non-uniform filiaments are produced for very fine filaments of less than 3 microns size. Under a.c. or ramped conditions, the junctions would probably cause unac- ceptably high losses and magnetization effects.
- the expanded mesh jelly roll technique is described in ⁇ .S. patent 4,262,412 to McDonald (assigned to Tteledyne Industries).
- the objects of the invention are met through a construction of composite superconductor which provides spread and uniformly spaced superconductor filaments.
- the filaments are within the range of 1-
- the average spacing between filaments is between 1 to 5 filament diameters.
- the product is made by rolling up a spiral of a woven wire layer.
- the layer has x - and y - axis wires.
- the x-wires (substan ⁇ tially parallel to the axis of spiral winding) comprise, for the most part or entirely, superconductor or precursor (prior to later heating to form such superconductor) selected from the class consisting of niobium, titanium, zirconium, vanadium, alloys thereof, normal metal coated (e.g. by copper, silver, aluminum, gold, tin or indium or alloys thereof) versions, bronze (copper-tin, copper-gallium, copper-aluminum) coated or cored versions thereof (to produce, e.g.
- niobium stannide or vanadium gallium or niobium aluminide in later heating niobium stannide or vanadium gallium or niobium aluminide in later heating
- suitable forms of niobium stannide or the like e.g. in thin layers trapped between refractory metal layers
- the y-axis layers comprise a normal metal and the weave is pre- ferrably tight enough to assure that x-wires do not slide together. In a loose weave, other means can be provided to avoid contact of wires.
- normal metal is placed between the spiral layers — by interleaved spiral winding therewith using continuous or discontinuous layers of normal metal foil or a normal metal woven layer or by casting low melting normal metal into a loose spiral of the main woven layer containing the x- axis superconductive wires.
- the spiral is wound around a normal metal core of solid or tube form.
- the spiral is solidified by isostatic press action or the like to form a billet, which is extruded to rod, tube or strip form.
- the extruded product which is essentially completely densified, may be further worked to finer cross section.
- the x-wires of superconducting material used in the original woven layer may, per se, be products of extrusion and drawing. Pre- ferrably such wires have normal metal coatings.
- FIG.l is an isometric sketch of billet preparation, a step in practice of a first preferred embodiment of the invention.
- FIG.2 is cross-section view of the same billet after extrusion and further reduction
- FIG.3 shows in cross-section the FIG.1 billet after extrusion into a tube and backfilling with a metal source (for later reaction with filaments, e.g. Sn for reaction with Nb, Ga for reacting with V, Al for reacting with Nb or V) ;
- a metal source for later reaction with filaments, e.g. Sn for reaction with Nb, Ga for reacting with V, Al for reacting with Nb or V
- FIG.4 shows, in cross-section, the FIG 3. product in multiples, hex formed and re-packed, to make a larger assembly which can be further reduced and eventually heat treated;
- FIGS. 5, 5A, 5B and 6 are isometric sketches illustrating further embodiments of the invention.
- FIG.1 shows that a billet 10 is made by wrapping several spiral turns of a woven metal fiber fabric 20 around a mandrel 30.
- the fabric can be in separate sheets for each one turn, or small groups of turns or in a single sheet spirally wound for dozens, or all of, the turns.
- the fabric comprises superconductor wires 22 running in the length direction of mandrel 30 (i.e. essentially parallel to axis 32 of mandrel 30, the ultimate direction E of later extrusion) , although a slight diagonal offset can be applied to introduce a twist into the wires 22.
- Crossing wires 24 of normal electrical conductivity, high thermal conductivity metal 24 are preferrably woven with wires 22.
- the wires 24 run essentially 90 degrees (plus or minus 30 degrees diagonal offset) with respect to longitudinal superconductor wires 22.
- the nature of the weave and its tightness are selected to maximize the number of superconductor wires 22, yet assure that adjacent super conductor wires do not touch (within a spiral fabric layer) .
- Normal metal wires 26 can be interspersed in the longitudinal direction, optionally.
- the spiral fabric layers are interleaved with similar spiral layers of normal metal in foil form, e.g. as shown at 28, or fabric (woven or non-woven) form to assure spacing of superconductor wires in the radial direction when the spiral turns are formed.
- the "superconductor wire” 22 can be a Type II superconductive niobium-alloy or a precursor (e.g. niobium or vanadium) of a compound form Type II superconductive compound, e.g. Ifc- j Sn or V 3 Ga formed by later high temperature reaction with a source of tin or gallium. Niobium aluminide and several other compounds can be formed, similarly.
- the alloy or compound can have two or more than two major components.
- each such superconductor wire 22 is continuous for the length of billet 10.
- Each wire may have a normal metal coating to enhance electrical isolation, subject to the drawback that coatings degrade smoothness over the course of working while bare metal (e.g. Nb) wires 22 would have greater tendency to smoothness and size uniformity in the course of working.
- the normal metal used in wires 24 (and 26, if provided) and. or in a coating, if provided, of wires 22 , and in the spiral interleaving layer 28 is preferrably copper, but may be gold, silver, aluminum, or other elements or a bronze (e.g. a copper-tin or copper-gallium bronze) . Combinations of normal metal can be used.
- wires 22, 24 and 26 are 10-30 mil diameter and a woven fabric form of layers 20 would, therefore, have high spots of 20-60 mils. Coatings if employed are 1-3 mils. If copper foil is used instead of a fabric as layer 28, it would be provided in 5-20 mil thickness and fabric forms of layer 28 would be made of 5-10 mil coppe wire with high spots (at fabric cross-overs) of 10-20 mils.
- the normal metal "wires" 24 layer 20 can be of ribbon form or of round, but lower diameter than 22 so that the fabric layer 20 comprises its component wires 22 essentially in the same (spiralled) plane.
- the rolled up billet 10 is initially 55-65% of theoretical density. It is isostatically pressed in accordance with preferred practice of the invention to 95-99% theoretical density then extruded and drawn to a rod form in a 100 to 1 reduction (area to area reduction, 10 to 1 on a diameter basis) to correspondingly reduce contained wires 22' (of twenty mils diameter, originally) to filaments (of two mils diameter) in a normal metal matrix derived from the normal metal wires and foil of the original billet, as shown in FIG.2. n some instances, it will be desirable to. extrude billet 10 to a tube rather than rod form, backfill the tube hole with tin or gallium or aluminum or an alloy thereof as indicated in FIG.3.
- the resultant rod can be hex formed and packed together with other simi ⁇ larly formed rods as shown in FIG.4, and cold worked as a group *
- thousands or tens of thousands of filaments of the necessary 1-10 micron diameter range can be provided in a single composite conductor with only a single extrusion heating of copper in contact with niobium, or the like in its processing history, to avoid undesired diffusion (that results from prior art dual heating steps) .
- an outer copper layer 42 (FIG.2) separated from the copper matrix 32 by an inert (e.g. tantalum) sheath 44, to form a final rod product 46.
- an inert e.g. tantalum sheath 44
- the core 34 derived from mandrel 30 of FIG.l or alternately a substitute core 34' as in FIG.3
- a copper matrix containing filaments 22' derived from wires 22
- the filaments 22* have essentially no tangential contact with each other — i.e. essentially all of the filaments being separated from each other by at least half of average filament diameter throughout 90% or more of length of rod 40, derived from billet 10 via the extrusion, and at least a micron apart, but not necessarily over 4 micron spacing, in any event.
- the product 46 comprising rod 40 (with its jacket 42 and bar ⁇ rier layer 44, applied before or after extrusion) can further reduced if desired by hot or cold swaging, drawing, rolling or other common metallurgical working techniques with associated heat treatments to optimize size and physical and electrical properties of the end product and its components.
- the 1-2 mil filaments can be reduced further to a .02 mil size (5 microns) or less.
- the assemblage of FIG.4 may include interspersed kinds of component hex rods, e.g. some comprising products of spiral winding and extrusion and having superconductor and a residual bronze therein and others having pure copper protected from diffusion by a tantalum layer.
- component hex rods e.g. some comprising products of spiral winding and extrusion and having superconductor and a residual bronze therein and others having pure copper protected from diffusion by a tantalum layer.
- FIGS. 5 - 6 show two further embodiments of the invention comprising respectively, for FIG. 5, a spiral wrap 110 of a weave of wires 122 (longitudinal or x-axis) with ribbons 124 (lateral or y- axis) and for FIG. 6 a spiral 210 of a lateral series of wires 222 overlaid (or underlaid) with a foil 224.
- the wires 122 and 222 comprise niobium-titanium alloy with a copper coating and an interweaving diffusion barrier layer of niobium or tantalum between the alloy core and the copper coat (to prevent adverse reaction of copper with the titanium component of the alloy) .
- the spiral may be formed as a rod or tube and processed similarly to processing of the spiral in connection with FIGS. 1 - 4 and related text above.
- the wires 122 and 222 are in the range of 5 - 20 mil diameter (typically 10 mils each, of which 8 - 9 mils is alloy and 1 - 2 mils is barrier layer double thicknesses — i.e. 0.5 - 1 mil layer thicknesses appearing twice on a cross section diameter) , with spacing being 1 - 4 mils (usually 2) between wires in FIG. 5.
- 5 - 20 mil diameter typically 10 mils each, of which 8 - 9 mils is alloy and 1 - 2 mils is barrier layer double thicknesses — i.e. 0.5 - 1 mil layer thicknesses appearing twice on a cross section diameter
- spacing being 1 - 4 mils (usually 2) between wires in FIG. 5.
- the wires are preferrably soldered or brazed to each other and/or the foil using the copper coat of the wire as all or part of a soldering or brazing medium effectively made at low heats (100 - 200 C) which do not appreciably advance oxidation of the alloy or at room temperature with pressure or ultrasonic vibration.
- a soldering or brazing medium effectively made at low heats (100 - 200 C) which do not appreciably advance oxidation of the alloy or at room temperature with pressure or ultrasonic vibration.
- the ribbons 124 of FIG. 5 are typically 5 - 10 wire diameters in width, i.e. 0.05 - 0.1 inches.
- the spirals 110 and or 210 can be continuous or segmented (end- to-end in the lateral direction with end joints or overlaps) . There may be as many as 35,000 wires 122 or 222 in the spirals of FIG. 5 or 6 (typically 20 ,000) . A very high proportion, in the ending cross-section of the spiral after compaction and extrusion, is achieved compared to prior art systems.
- FIG. 5A shows a variant of the FIG. 5 construction wherein instead of using discrete ribbon foils 124, a single sheet 125 is slit with multiple through cuts 123 all parallel and lateral, for form component ribbons 124A including end ribbons a . J ⁇ , and Q.
- Each of the ribbon components is corrugated and the corresponding corrugations are offset by one from adjacent ribbon component to adjacent ribbon component.
- a wire 122-1 passes under corrugations a-1 and c-1 while wire 122-2 passes over ribbon components a and c but under corrugation b-1.
- FIG. 5B shows a further aspect of the use of FIG. 5 construction in that wires 122-M of a turn M nest with wires 122-N of the next adjacent turn N of a spiral.
- FIG. 6B shows a forward ribbon 124F and a rear ribbon 124R. But the nesting advantage, for higher packing factor and ultimately high proportion of superconductive niobium alley, is achieved also in the FIG. 5A and
- FIG 6A constructions as well, while gaining the benefits of round wire/filament form for components 122.
- bronze sources of tin, gallium or the like can be correlated with refractory metal for formation of compounds in accordance with state of the art knowledge, shown, e.g., in British patent 1,535,971 (Toshiba) , J. Appl. Phys., 49:6020 (1978) , U.S. patents 3 ,731,374 (Suenega) 3 ,838 ,503 (Suenega) , 3 ,910 ,801 and 802 (Wong/Supercon,Inc.) , 4,043,028 (Showa Electric).
- the extrusion can be supplemented or displaced by other forms of hot or cold working elongation in ⁇ cluding rolling swaging, and drawing.
- he spiral cylinder described above can be flattened — in some applications not requiring central axis symmetry — to provide an elliptical (central plan symmetry) rather than a circular spiral.
- the spiral can be substituted by a fanfold in some instances.
- the invention can be applied to plural superposed layers of fabric which are not part of a continuous layer.
Abstract
A superconductor wire (46) with multi-filaments is made by extrusion of a billet (10) formed by spiral wrapping a woven layer (20) of superconductor wires (22) and normal metal wires (24) to provide an extrusion billet which will maintain separation of component superconductor wires during extrusion and subsequent processing to ensure separation of superconductor filaments in the final product.
Description
MULTI-FILfiMENT SϋPERCOND fCTOR WIRE PRODUCTION BACKGROUND OP USE INVENTION The present invention relates to production of multifilament superconductive wires of the class comprising 5,000 - 35,000 of such filaments in a wire.
Ωie conventional technique of assembling copper-coated super¬ conductors into a billet and extruding is unsuitable for such purpose. Generally these billets are made, under conventional practice by inserting Nb-Ti rods into copper tubes, bundling into a copper billet tube and extruding. Alternatively, a copper billet can be pre-drilled with longitudinal holes, each of which is filled by a Nb-Ti rod (per se or with a coat of copper) The technique is also used with niobium or vanadium rods which can be reacted later to form b3Sn or V3Ga. As the starting billet can be varied only slightly, this requires the manufacturer to make much smaller tubing, with concomitant problems related to straightness, twist and the cleanliness of the inner diameter. While other techniques have been suggested, they all have drawbacks that make their use questionable. One of the earliest suggestions was to assemble a billet with a moderate number of filaments, say 150, extrude and draw this to a size where it could be cut into 150 pieces and assembled into another billet, extruded and drawn to a wire with 150 x 150 or 22500 filaments. Unfortunately, copper and titanium from the l_b-Ti alloy filaments interdiffuse when heated for the second extrusion to an even greater extent than during the first extrusion, to form a deleterious layer around each filament. Even greater complexity is involved in Nb3Sn or V3Ga manufacture by this approach.
Another prior art technique is the use of expanded Nb-Ti mesh in a "jelly roll" type billet. While this technique simplifies the manufacture of fine filaments, it has the drawback that there are periodic junctions between filaments which may limit use to d.c. coils. An additional drawback is that non-uniform filiaments are produced for very fine filaments of less than 3 microns size. Under a.c. or ramped conditions, the junctions would probably cause unac- ceptably high losses and magnetization effects.
The expanded mesh jelly roll technique is described in ϋ.S. patent 4,262,412 to McDonald (assigned to Tteledyne Industries).
It is an object of the invention to provide a means of produ¬ cing fine filament superconductor overcoming the foregoing problems. It is a further object of the invention to provide a superconr- ductor wire with 5,000 - 35,000 filaments therein of high uniformity of cross section, with the filaments being spaced from each other.
SUMMMff OF THE INVEMTION
The objects of the invention are met through a construction of composite superconductor which provides spread and uniformly spaced superconductor filaments. The filaments are within the range of 1-
10 microns diameter and substantially uniform (within 2 microns) in such range. The average spacing between filaments is between 1 to 5 filament diameters. The avoidance of junctions enables usage of the composite for alternating current situations.
The product is made by rolling up a spiral of a woven wire layer. The layer has x - and y - axis wires. The x-wires (substan¬ tially parallel to the axis of spiral winding) comprise, for the most part or entirely, superconductor or precursor (prior to later heating to form such superconductor) selected from the class consisting of niobium, titanium, zirconium, vanadium, alloys thereof, normal metal coated (e.g. by copper, silver, aluminum, gold, tin or indium or alloys thereof) versions, bronze (copper-tin, copper-gallium, copper-aluminum) coated or cored versions thereof (to produce, e.g. niobium stannide or vanadium gallium or niobium aluminide in later heating) and suitable forms of niobium stannide or the like (e.g. in thin layers trapped between refractory metal layers) .
The y-axis layers comprise a normal metal and the weave is pre- ferrably tight enough to assure that x-wires do not slide together. In a loose weave, other means can be provided to avoid contact of wires.
In rolling the woven layer into a spiral, normal metal is placed between the spiral layers — by interleaved spiral winding therewith using continuous or discontinuous layers of normal metal foil or a normal metal woven layer or by casting low melting normal
metal into a loose spiral of the main woven layer containing the x- axis superconductive wires.
The spiral is wound around a normal metal core of solid or tube form. The spiral is solidified by isostatic press action or the like to form a billet, which is extruded to rod, tube or strip form.
The extruded product, which is essentially completely densified, may be further worked to finer cross section.
In the extrusion, through a diameter reduction ratio in the range of 5:1 to 20:1, the x-axis superconducting filaments are cor*- respondingly reduced from typical diameter of millimeter range to final diameter of 1 to 50 microns (and through further working, after extrusion to 1 to 5 microns; 25 microns = .001 inch = 1 mil) .
The x-wires of superconducting material used in the original woven layer may, per se, be products of extrusion and drawing. Pre- ferrably such wires have normal metal coatings.
Other objects, features and advantages will be apparent from the following detailed description of preferred embodiments thereof taken in connection with the accompanying drawing. BRIEF DESCRIPTION OF THE DRWING FIG.l is an isometric sketch of billet preparation, a step in practice of a first preferred embodiment of the invention.
FIG.2 is cross-section view of the same billet after extrusion and further reduction;
FIG.3 shows in cross-section the FIG.1 billet after extrusion into a tube and backfilling with a metal source (for later reaction with filaments, e.g. Sn for reaction with Nb, Ga for reacting with V, Al for reacting with Nb or V) ;
FIG.4 shows, in cross-section, the FIG 3. product in multiples, hex formed and re-packed, to make a larger assembly which can be further reduced and eventually heat treated; and
FIGS. 5, 5A, 5B and 6 are isometric sketches illustrating further embodiments of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIG.1 shows that a billet 10 is made by wrapping several spiral turns of a woven metal fiber fabric 20 around a mandrel 30. The fabric can be in separate sheets for each one turn, or small groups
of turns or in a single sheet spirally wound for dozens, or all of, the turns. In either case the fabric comprises superconductor wires 22 running in the length direction of mandrel 30 (i.e. essentially parallel to axis 32 of mandrel 30, the ultimate direction E of later extrusion) , although a slight diagonal offset can be applied to introduce a twist into the wires 22. Crossing wires 24 of normal electrical conductivity, high thermal conductivity metal 24 are preferrably woven with wires 22. The wires 24 run essentially 90 degrees (plus or minus 30 degrees diagonal offset) with respect to longitudinal superconductor wires 22. The nature of the weave and its tightness are selected to maximize the number of superconductor wires 22, yet assure that adjacent super conductor wires do not touch (within a spiral fabric layer) . Normal metal wires 26 can be interspersed in the longitudinal direction, optionally. The spiral fabric layers are interleaved with similar spiral layers of normal metal in foil form, e.g. as shown at 28, or fabric (woven or non-woven) form to assure spacing of superconductor wires in the radial direction when the spiral turns are formed.
The "superconductor wire" 22 can be a Type II superconductive niobium-alloy or a precursor (e.g. niobium or vanadium) of a compound form Type II superconductive compound, e.g. Ifc-jSn or V3Ga formed by later high temperature reaction with a source of tin or gallium. Niobium aluminide and several other compounds can be formed, similarly. The alloy or compound can have two or more than two major components. Preferrably each such superconductor wire 22 is continuous for the length of billet 10. Each wire may have a normal metal coating to enhance electrical isolation, subject to the drawback that coatings degrade smoothness over the course of working while bare metal (e.g. Nb) wires 22 would have greater tendency to smoothness and size uniformity in the course of working.
The normal metal used in wires 24 (and 26, if provided) and. or in a coating, if provided, of wires 22 , and in the spiral interleaving layer 28 is preferrably copper, but may be gold, silver, aluminum, or other elements or a bronze (e.g. a copper-tin or copper-gallium bronze) . Combinations of normal metal can be used.
Typically wires 22, 24 and 26 are 10-30 mil diameter and a woven fabric form of layers 20 would, therefore, have high spots of 20-60 mils. Coatings if employed are 1-3 mils. If copper foil is used instead of a fabric as layer 28, it would be provided in 5-20 mil thickness and fabric forms of layer 28 would be made of 5-10 mil coppe wire with high spots (at fabric cross-overs) of 10-20 mils.
The normal metal "wires" 24 layer 20 can be of ribbon form or of round, but lower diameter than 22 so that the fabric layer 20 comprises its component wires 22 essentially in the same (spiralled) plane.
The rolled up billet 10 is initially 55-65% of theoretical density. It is isostatically pressed in accordance with preferred practice of the invention to 95-99% theoretical density then extruded and drawn to a rod form in a 100 to 1 reduction (area to area reduction, 10 to 1 on a diameter basis) to correspondingly reduce contained wires 22' (of twenty mils diameter, originally) to filaments (of two mils diameter) in a normal metal matrix derived from the normal metal wires and foil of the original billet, as shown in FIG.2. n some instances, it will be desirable to. extrude billet 10 to a tube rather than rod form, backfill the tube hole with tin or gallium or aluminum or an alloy thereof as indicated in FIG.3. The resultant rod can be hex formed and packed together with other simi¬ larly formed rods as shown in FIG.4, and cold worked as a group* In this way thousands or tens of thousands of filaments of the necessary 1-10 micron diameter range can be provided in a single composite conductor with only a single extrusion heating of copper in contact with niobium, or the like in its processing history, to avoid undesired diffusion (that results from prior art dual heating steps) .
In most embodiments it is desirable to provide an outer copper layer 42 (FIG.2) separated from the copper matrix 32 by an inert (e.g. tantalum) sheath 44, to form a final rod product 46. containing the core 34 (derived from mandrel 30 of FIG.l or alternately a substitute core 34' as in FIG.3) surrounded by a copper matrix containing filaments 22' (derived from wires 22) in
-6-
the copper matrix 32. The filaments 22* have essentially no tangential contact with each other — i.e. essentially all of the filaments being separated from each other by at least half of average filament diameter throughout 90% or more of length of rod 40, derived from billet 10 via the extrusion, and at least a micron apart, but not necessarily over 4 micron spacing, in any event.
The product 46 comprising rod 40 (with its jacket 42 and bar¬ rier layer 44, applied before or after extrusion) can further reduced if desired by hot or cold swaging, drawing, rolling or other common metallurgical working techniques with associated heat treatments to optimize size and physical and electrical properties of the end product and its components. For instance the 1-2 mil filaments can be reduced further to a .02 mil size (5 microns) or less.
The assemblage of FIG.4 may include interspersed kinds of component hex rods, e.g. some comprising products of spiral winding and extrusion and having superconductor and a residual bronze therein and others having pure copper protected from diffusion by a tantalum layer.
FIGS. 5 - 6 show two further embodiments of the invention comprising respectively, for FIG. 5, a spiral wrap 110 of a weave of wires 122 (longitudinal or x-axis) with ribbons 124 (lateral or y- axis) and for FIG. 6 a spiral 210 of a lateral series of wires 222 overlaid (or underlaid) with a foil 224. The wires 122 and 222 comprise niobium-titanium alloy with a copper coating and an interweaving diffusion barrier layer of niobium or tantalum between the alloy core and the copper coat (to prevent adverse reaction of copper with the titanium component of the alloy) . The spiral may be formed as a rod or tube and processed similarly to processing of the spiral in connection with FIGS. 1 - 4 and related text above. The wires 122 and 222 are in the range of 5 - 20 mil diameter (typically 10 mils each, of which 8 - 9 mils is alloy and 1 - 2 mils is barrier layer double thicknesses — i.e. 0.5 - 1 mil layer thicknesses appearing twice on a cross section diameter) , with spacing being 1 - 4 mils (usually 2) between wires in FIG. 5. In FIG. 6 the wires are preferrably soldered or brazed to each other and/or the foil using
the copper coat of the wire as all or part of a soldering or brazing medium effectively made at low heats (100 - 200 C) which do not appreciably advance oxidation of the alloy or at room temperature with pressure or ultrasonic vibration. Such bonding facilitates handling of the assemblage.
The ribbons 124 of FIG. 5 are typically 5 - 10 wire diameters in width, i.e. 0.05 - 0.1 inches.
The spirals 110 and or 210 can be continuous or segmented (end- to-end in the lateral direction with end joints or overlaps) . There may be as many as 35,000 wires 122 or 222 in the spirals of FIG. 5 or 6 (typically 20 ,000) . A very high proportion, in the ending cross-section of the spiral after compaction and extrusion, is achieved compared to prior art systems.
FIG. 5A shows a variant of the FIG. 5 construction wherein instead of using discrete ribbon foils 124, a single sheet 125 is slit with multiple through cuts 123 all parallel and lateral, for form component ribbons 124A including end ribbons a . J≥, and Q. Each of the ribbon components is corrugated and the corresponding corrugations are offset by one from adjacent ribbon component to adjacent ribbon component. Thus a wire 122-1 passes under corrugations a-1 and c-1 while wire 122-2 passes over ribbon components a and c but under corrugation b-1.
FIG. 5B shows a further aspect of the use of FIG. 5 construction in that wires 122-M of a turn M nest with wires 122-N of the next adjacent turn N of a spiral. FIG. 6B shows a forward ribbon 124F and a rear ribbon 124R. But the nesting advantage, for higher packing factor and ultimately high proportion of superconductive niobium alley, is achieved also in the FIG. 5A and
■ FIG 6A constructions as well, while gaining the benefits of round wire/filament form for components 122.
In accordance with the present invention, bronze sources of tin, gallium or the like can be correlated with refractory metal for formation of compounds in accordance with state of the art knowledge, shown, e.g., in British patent 1,535,971 (Toshiba) , J. Appl. Phys., 49:6020 (1978) , U.S. patents 3 ,731,374 (Suenega) 3 ,838 ,503 (Suenega) , 3 ,910 ,801 and 802 (Wong/Supercon,Inc.) ,
4,043,028 (Showa Electric).
It is also contemplated that the extrusion can be supplemented or displaced by other forms of hot or cold working elongation in¬ cluding rolling swaging, and drawing. he spiral cylinder described above can be flattened — in some applications not requiring central axis symmetry — to provide an elliptical (central plan symmetry) rather than a circular spiral. The spiral can be substituted by a fanfold in some instances. Further, the invention can be applied to plural superposed layers of fabric which are not part of a continuous layer.
It will not be apparent to those skilled in the art that other embodiments, improvements, details, and uses can be made consistent with the letter and spirit of the foregoing disclosure and within the scope of this patent, which is limited only by the following claims, construed in accordance with the patent law, including the doctrine of equivalents.
What is claimed is:
Claims
1. An elongated composite comprising a high conductivity nor¬ mal metal matrix with dispersed continuous filaments thereof of T_ηp II superconductor of a uniform diameter in the range of 1 to 10 microns and in a number in the range of 5,000 — 35,000 filaments, as made by elongating a spiral roll array of superconductor wires, which are radially and peripherally spaced.
2. Composite in accordance with claim 1 wherein the spacing is provided by multi-layer of superposed woven array of x-direction superconductive wires with y-direction normal metal elements substantially orthogonal thereto and the layers of such x and y wires being spirally wound.
3. Composite in accordance with claim 2 wherein the normal wires and matrix are made of copper.
4. Composite in accordance with claim 2 wherein the supercon¬ ductive wire is niobium-titanium alloy.
7. Composite in accordance with claim 2 wherein superconduc¬ tive wire is a Nt^Al compound.
8. Composite in accordance with claim 2 wherein the supercon¬ ductive wire composite comprises a bundle of component sub- composites, each of which has a spirally rolled up woven array of x- direction superconductive wires with y-direction normal metal wires.
9. Method of making an elongated metal composite comprising filaments of a refractory metal in a matrix comprising the steps of spirally wrapping a sheet containing wires of the refractory metal extending essentially parallel to each other and substantially hori¬ zontal to the planes of spiral turning, maintaining the wires radially and peripherally spaced from each other in the spiral wrap, providing a matrix metal in the wrap, densifying and extruding the product to elongate the product and its component wires while maintaining the relative spacing of wires and reducing the cross- size thereof substantially uniformly.
10. Method in accordance with claim 9 and comprising the further step of cold work elongation of the extruded product.
11. Method in accordance with claim 9 wherein the matrix is provided at least in part by interleaving turns of spirally wound matrix metal layer with said sheet.
12. Method in accordance with claim 11 wherein the matrix metal layer is a foil.
13. Method in accordance with claim 9 wherein the sheet com¬ prises matrix metal wires cross-woven with the refractory metal 0 wires.
14. Method in accordance with claim 13 wherein the sheet comprises matrix metal wires running parallel to the refractory metal wires and interspersed therewith.
15. Method in accordance with claim 9 and further comprising 5 insertion in the product of a source of further material which is capable of reacting with the refractory metal to form a compund thereof .
16. Method in accordance with claim 15 wherein the source of further material is an alloy of matrix and further material. 0
17. The process of forming a superconductor which comprises the steps of: a) weaving a fabric of a first metal wire and a second metal wire, the first metal wire being selected from the class of metals which are superconductors or which can be converted to 5 superconductors by reaction with another material, the second metal wire being a normal metal; b) rolling said fabric into a spiral to form a tightly compac¬ ted billet, the first metal wires in the fabric spiral being generally parallel to the axis of the billet and being separated ° from each other by a normal metal through substantially all their length; c) elongating said billet in a direction parallel to its axis; d) further reducing said billet to reduce the diameter of the first wires to a size on the order of 1-10 microns. 5
18. Process in accordance with claim 17 and further comprising the step of compacting said spiral to produce a relatively solid
-II -
billet.
19. Process in accordance with claim 17 and further comprising the step of compacting said billet to increase its density.
20. Process in accordance with claim 17 and further comprising the step of reducing the diameter of said billet by swaging, extruding or the like.
21. Process in accordance with claim 17 wherein the first wires are separated from each other throughout their length.
22. Process in accordance with claim 17 wherein the first metal wires are not superconductive as extruded but are reacted with a component in said normal metal to form a superconductor.
23. Process in accordance with claim 17 in which the said normal metal comprises a constituent which will react with the first metal to form a superconductor.
24. Process in accordance with claim 17 in which a multipli¬ city of said first wires is provided in a composite body and further comprising the step of reducing the body to provide a final product having at least 5000 individual superconducting wires therein.
25. Process in accordance with claim 17 in which the product is extruded into the form of a tube and the tube contains material which can react with the metal of the first wires for forming said final superconductor.
26. Process in accordance with claim 17 in which each layer of the fabric spiral is separated from the adjacent such fabric spiral layer by a layer of normal metal.
27. The process of forming a superconductor which comprises the steps of: a) providing a fabric comprising superconducting metal strands which extend in one direction and normal metal strands which extend in a transverse direction; b) forming an assembly of said fabric by superposing a plur¬ ality of layers of said fabric, each layer being separated from the adjacent layer so that a layer of normal metal separates each super¬ conductor strand; c) compacting said assembly and elongating the assembly in the direction of the superconducting strands by one or more of the
working steps of extruding, rolling, drawing, swaging and the like, to provide a final product having elongated superconducting strands with a thickness of 1 to 10 microns.
28. Process in accordance with claim 27 wherein each first metal strand is a niobium-titanium superconductive alley coated with a normal metal of higher thermal conductivity and comprising an interweaving barrier in an aggregate wire form, the second strand is a ribbon of normal metal and the wires of adjacent superposed layers are nested.
29. Process in accordance with claim 28 wherein the ribbon strands are part of a continuous slit foil and comprise corrugations offset by one in adjacent ribbons.
30. A superconductor composite product as made by the process of claim 27.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US60524784A | 1984-04-30 | 1984-04-30 | |
US605,247 | 1984-04-30 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO1986001677A2 true WO1986001677A2 (en) | 1986-03-27 |
WO1986001677A1 WO1986001677A1 (en) | 1986-03-27 |
Family
ID=24422862
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1985/000792 WO1986001677A1 (en) | 1984-04-30 | 1985-04-30 | Multi-filament superconductor wire production |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0190348A1 (en) |
WO (1) | WO1986001677A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5104849A (en) * | 1989-06-06 | 1992-04-14 | The Furukawa Electric Co., Ltd. | Oxide superconductor and method of manufacturing the same |
Family Cites Families (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1054784A (en) * | 1908-02-27 | 1913-03-04 | Western Electric Co | Electric cable. |
US3570118A (en) * | 1967-03-10 | 1971-03-16 | Westinghouse Electric Corp | Method of producing copper clad superconductors |
US3443021A (en) * | 1967-04-28 | 1969-05-06 | Rca Corp | Superconducting ribbon |
US3813764A (en) * | 1969-06-09 | 1974-06-04 | Res Inst Iron Steel | Method of producing laminated pancake type superconductive magnets |
US3582537A (en) * | 1969-11-26 | 1971-06-01 | Haveg Industries Inc | Woven cable with bonded woven lattice structure |
US3708606A (en) * | 1970-05-13 | 1973-01-02 | Air Reduction | Cryogenic system including variations of hollow superconducting wire |
US3909508A (en) * | 1970-05-18 | 1975-09-30 | Southern Weaving Co | Woven electrically conductive cable and method |
US3828417A (en) * | 1970-08-26 | 1974-08-13 | Commw Scient Corp | Method for fabricating composite material reinforced by uniformaly spaced filaments |
US3910802A (en) * | 1974-02-07 | 1975-10-07 | Supercon Inc | Stabilized superconductors |
US4260441A (en) * | 1978-05-10 | 1981-04-07 | United Technologies Corporation | Quick bond composite and process |
US4205119A (en) * | 1978-06-29 | 1980-05-27 | Airco, Inc. | Wrapped tantalum diffusion barrier |
US4414428A (en) * | 1979-05-29 | 1983-11-08 | Teledyne Industries, Inc. | Expanded metal containing wires and filaments |
US4262412A (en) * | 1979-05-29 | 1981-04-21 | Teledyne Industries, Inc. | Composite construction process and superconductor produced thereby |
CH641911A5 (en) * | 1979-06-05 | 1984-03-15 | Bbc Brown Boveri & Cie | SUPERCONDUCTIVE CABLE. |
US4447946A (en) * | 1979-09-10 | 1984-05-15 | Airco, Inc. | Method of fabricating multifilament intermetallic superconductor |
SE420964B (en) * | 1980-03-27 | 1981-11-09 | Asea Ab | COMPOSITION MATERIAL AND SET FOR ITS MANUFACTURING |
-
1985
- 1985-04-30 EP EP86900998A patent/EP0190348A1/en not_active Withdrawn
- 1985-04-30 WO PCT/US1985/000792 patent/WO1986001677A1/en unknown
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