CN112489884B - Iron-based superconducting composite wire and preparation method thereof - Google Patents
Iron-based superconducting composite wire and preparation method thereof Download PDFInfo
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- CN112489884B CN112489884B CN202011317360.6A CN202011317360A CN112489884B CN 112489884 B CN112489884 B CN 112489884B CN 202011317360 A CN202011317360 A CN 202011317360A CN 112489884 B CN112489884 B CN 112489884B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
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- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
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- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Abstract
The invention provides an iron-based superconducting composite wire and a preparation method thereof, and relates to the technical field of iron-based superconducting materials. The preparation method provided by the invention comprises the following steps: packaging n iron-based superconducting single-core wires and m metal bars into an outer-layer packaging sleeve for assembly to obtain a final-stage complex; wherein n is more than or equal to 1, and m is more than or equal to 0; and carrying out grooved rolling and heat treatment on the final-stage composite body in sequence to obtain the iron-based superconducting composite wire. The preparation method provided by the invention not only can improve the density of the iron-based superconducting composite wire rod, but also can form stronger texture, thereby improving the current carrying capacity of the wire rod. The method is simple and easy to operate, has low preparation cost and is suitable for industrialized popularization and application.
Description
Technical Field
The invention relates to the technical field of iron-based superconducting materials, in particular to an iron-based superconducting composite wire and a preparation method thereof.
Background
The iron-based superconducting material is a novel high-temperature superconducting material with a crystal structure containing a FeAs layer or a FeSe layer, and has the advantages of high upper critical field, high critical current density, low anisotropism and the like. The iron-based superconducting wire strip prepared by adopting the powder tubing method (PowderInTube, PIT) has low cost and better high-field current carrying capacity, and is expected to be applied to next-generation high-energy accelerators, high-field magnets and nuclear magnetic resonance imaging systems. The iron-based superconducting wire includes an outer metal sheath and an inner superconducting core, which is responsible for carrying the superconducting current, as shown in fig. 1 (a). The single-core wire tape having only one core wire and the multi-core wire tape having a plurality of core wires can be divided according to the number of the superconducting core wires therein. The iron-based superconducting wire tape may be further divided into a tape and a wire according to its shape. Wherein the cross section of the strip material is flat, and the length-width ratio is as high as 10-20; the wire has a cross-section close to circular and an aspect ratio close to 1. At present, the preparation technology of the iron-based superconducting tape has made breakthrough progress, hundreds of meters of the iron-based superconducting tape has been prepared internationally, and the iron-based superconducting tape is wound into a cake-shaped coil and a runway-shaped coil, and still has better performance under a high field, and the forward practical stage of the iron-based superconducting material is marked. However, the use of strips in certain applications is limited by their special shape. Compared with the prior art, the wire can be wound into the solenoid coil, so that the solenoid coil is more convenient for practical application. The current wire rod preparation technology level is low, relies on expensive hot isostatic pressing equipment, and texture is difficult to introduce into the wire rod, the performance of the wire rod is far lower than that of a strip material, and the practical application of the wire rod is severely restricted. A great deal of researches show that the current carrying capacity of the iron-based superconducting wire is closely related to the density and the texture of the superconducting core. The vickers hardness is widely used internationally to evaluate the density of superconducting cores. The higher the vickers hardness, the higher the density. The density of the superconducting core is improved, holes and cracks are reduced, and therefore the effective current transmission area is increased. The superconductive core of the wire rod prepared by the traditional cold working processes such as rotary forging, drawing and the like has a large number of holes and cracks, and the Vickers hardness is only 50-80, so that the current carrying capacity of the wire rod is severely restricted. At present, the wire can only be subjected to heat treatment through hot isostatic pressing equipment, so that the density of the superconducting core of the wire is improved, and the Vickers hardness reaches 200HV. However, the hot isostatic pressing equipment is high in price, high in sintering cost, strict in technical requirements and low in yield, and the preparation cost of the wire rod is increased. Secondly, there is a weak connection effect in the iron-based superconducting wire, and when the grain boundary angle is more than 9 degrees, the inter-grain current drops sharply. Thus, the introduction of texture in the superconducting core is beneficial to improving the intergranular current. At present, the preparation process of the iron-based superconducting wire cannot form texture in the superconducting core, and the current is restricted from being further improved. In summary, how to improve the density and the texture of the iron-based superconducting wire by the conventional low-cost method is a difficult problem in the current practical process of the iron-based superconducting wire.
In the processing process of the iron-based superconducting wire, the wire is generally prepared by adopting a rotary forging and drawing mode. After normal pressure annealing, the texture and density of the superconducting core are very low, resulting in weak current carrying capacity. Therefore, the wire must be subjected to a subsequent annealing treatment by hot isostatic pressing (Hot Isostatic Pressing, HIP), which increases the ambient pressure during annealing and provides an isotropic pressure (typically up to 200 MPa) to the wire, thereby increasing the density of the superconducting core. However, HIP technology relies on expensive, precision hot isostatic presses, which make it difficult to reduce manufacturing costs. Furthermore, the HIP process cannot introduce high texture in the wire, resulting in difficulty in further improvement of critical current density. Therefore, after the wire rod is prepared by rotary forging and drawing, the wire rod is processed into a strip through flat roll rolling, and a stronger c-axis texture is introduced, so that the high critical current density is realized. However, the application surface of the strip material is narrow, and the strip material can be prepared into a pancake coil, but the solenoid is difficult to wind. The anisotropy of the cross section of the wire is weaker, and the wire has unique advantages on the winding of a superconducting magnet and is an ideal conductor for strong electricity application. Therefore, a conventional processing mode which does not depend on precise and expensive hot isostatic pressing equipment needs to be developed, the compactness and the texture of the iron-based superconducting wire are improved, the potential of large-scale production is provided, and the high-performance and low-cost hundred-meter or even kilometer-grade superconducting wire is prepared.
Disclosure of Invention
The invention aims to provide an iron-based superconducting composite wire and a preparation method thereof.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of an iron-based superconducting composite wire, which comprises the following steps:
packaging n iron-based superconducting single-core wires and m metal bars into an outer-layer packaging sleeve for assembly to obtain a final-stage complex; wherein n is more than or equal to 1, and m is more than or equal to 0;
and carrying out grooved rolling and heat treatment on the final-stage composite body in sequence to obtain the iron-based superconducting composite wire.
Preferably, before the n iron-based superconducting single-core wires and the m metal bars are put into the outer sheath tube, the method further comprises: firstly, n iron-based superconducting single-core wires and m metal bars are put into a tundish sleeve for assembly, so that a primary complex is obtained; the primary complex is then encased in an outer sheath to give a final complex.
Preferably, the sheathing material of the iron-based superconducting single-core wire is silver or silver alloy.
Preferably, the metal bar is made of nickel, nickel alloy, copper alloy, silver alloy, hastelloy or stainless steel.
Preferably, the material of the outer layer cladding tube is one of titanium, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, cadmium, hafnium, tantalum, tungsten and lead, or any one of alloys of the above metals.
Preferably, the outer layer sheath is made of stainless steel, monel, copper, tantalum, iron or hastelloy.
Preferably, when n >1, m=1, the iron-based superconducting single-core wire and the metal bar are assembled in the following manner: the metal bar is arranged at the centers of the iron-based superconducting single-core wires, and the iron-based superconducting single-core wires surround the metal bar along the circumferential direction.
Preferably, the pass of the grooved roll is a c-sided polygon, wherein c is more than or equal to 3.
Preferably, the temperature of the heat treatment is 500-1400 ℃, the heat treatment is carried out under inert atmosphere or vacuum condition, and the pressure is 10 -5 ～10 5 Pa。
The invention provides the iron-based superconducting composite wire prepared by the preparation method.
The invention provides a preparation method of an iron-based superconducting composite wire, which comprises the following steps: packaging n iron-based superconducting single-core wires and m metal bars into an outer-layer packaging sleeve for assembly to obtain a final-stage complex; wherein n is more than or equal to 1, and m is more than or equal to 0; and carrying out grooved rolling and heat treatment on the final-stage composite body in sequence to obtain the iron-based superconducting composite wire. The final cold working means adopted by the invention is grooved rolling, and isotropic high compression force is provided in the process of working deformation; the outer layer sleeve tube is strongly contracted towards the center under the action of grooved rolling, and provides huge compressive stress for the central superconducting core, so that the density of the superconducting core is greatly improved, and meanwhile, the extension stress along the axial direction of the wire rod is provided, so that the flaky superconducting crystal grains lie down along the wire rod core to form a local c-axis texture; according to the invention, the metal bar is added into the iron-based superconducting composite wire, and in the grooved rolling process, the inner metal bar is matched with the outer sheath tube, and meanwhile, the iron-based superconducting single core is extrudedThe wire rod forms local axial pressure, so that not only is the density of the superconducting core improved, but also a stronger c-axis texture is formed under the axial pressure, and the current carrying capacity of the wire rod is improved. Through tests, the hardness of the superconductive core in the iron-based superconductive composite wire rod prepared by the invention is up to 400HV, the density is up to 100%, and the critical current density under 4.2K and 10T is 1.1X10 4 ～1.2×10 5 A/cm 2 . The preparation method provided by the invention can not only improve the density of the iron-based superconducting composite wire rod, but also form stronger c-axis texture, thereby improving the current carrying capacity of the wire rod. Moreover, compared with the conventional processing mode relying on precise and expensive hot isostatic pressing equipment, the method is simple and easy to operate, has lower preparation cost and is suitable for industrialized popularization and application.
Drawings
Fig. 1 is a cross-sectional view of an iron-based superconducting single core composite wire prepared in example 1, a cross-sectional view of a seven-core iron-based superconducting composite wire prepared in example 2, and schematic diagrams of final composites of examples 3 and 4;
FIG. 2 is a graph showing the critical current density of the seven-core iron-based superconducting composite wire prepared in example 2 at 4.2K as a function of magnetic field;
fig. 3 is a graph showing the vickers hardness profile of the superconducting core in the seven-core iron-based superconducting composite wire prepared in example 2.
Detailed Description
The invention provides a preparation method of an iron-based superconducting composite wire, which comprises the following steps:
packaging n iron-based superconducting single-core wires and m metal bars into an outer-layer packaging sleeve for assembly to obtain a final-stage complex; wherein n is more than or equal to 1, and m is more than or equal to 0;
and carrying out grooved rolling and heat treatment on the final-stage composite body in sequence to obtain the iron-based superconducting composite wire.
According to the invention, n iron-based superconducting single-core wires and m metal bars are put into an outer-layer cladding sleeve for assembly, so that a final-stage complex is obtained; wherein n.gtoreq.1, preferably 1 to 18, more preferably 4 to 7, in particular embodiments of the invention n is particularly preferably 1, 4, 6, 7 or 18; m is greater than or equal to 0, preferably 1, 3, 4, 6, 8 or 10.
The preparation method of the iron-based superconducting single-core wire rod has no special requirement, and the preparation method well known to the person skilled in the art can be adopted. In the present invention, the sheathing material of the iron-based superconducting single-core wire is preferably silver or a silver alloy, more preferably silver, a silver-tin alloy, a silver-manganese alloy, or a silver-magnesium alloy. In the invention, the silver and silver alloy have better processing performance and can prevent the reaction with the superconducting core of the iron-based superconducting wire. In the invention, the material of the iron-based superconductor precursor powder in the iron-based superconducting single-core wire is preferably Ba1-xKxFe2As2, sr1-xKxFe2As2, baFe2-xCoxAs2, smFeAsO1-xFx or CaKFe4As4.
In the present invention, the cross-sectional shape of the iron-based superconducting single core wire is preferably regular hexagon, square, or circle. The invention has no special requirement on the size of the iron-based superconducting single-core wire rod, and can be manufactured according to actual requirements.
In the present invention, when the number n of the iron-based superconducting single-core wires is greater than 1, it is preferable to prepare one iron-based superconducting single-core wire first, and then divide the iron-based superconducting single-core wire into a plurality of segments, thereby obtaining a plurality of iron-based superconducting single-core wires.
In the present invention, the metal bar is preferably nickel, nickel alloy, copper alloy, silver alloy, hastelloy or stainless steel. According to the invention, the metal bar is added into the iron-based superconducting composite wire, and in the grooved rolling process, the inner metal bar is matched with the outer sheath tube, and meanwhile, the iron-based superconducting single-core wire is extruded to form local axial pressure, so that not only is the density of the superconducting core improved, but also a stronger c-axis texture is formed under the axial pressure, and therefore, the current carrying capacity of the wire is improved.
In the present invention, the cross-sectional shape of the metal bar is preferably regular hexagon, square or circle; the invention has no special requirement on the size of the metal bar, and the metal bar is manufactured according to actual requirements. In the present invention, the shape and size of the metal bar preferably conform to the iron-based superconducting single core wire.
In the present invention, when n >1, m=1, the assembly method of the iron-based superconducting single-core wire and the metal bar is preferably as follows: the metal bar is arranged at the centers of the iron-based superconducting single-core wires, and the iron-based superconducting single-core wires surround the metal bar along the circumferential direction. In a specific embodiment of the present invention, the plurality of iron-based superconducting single-core wires are uniformly distributed on the surface of the metal bar. In the invention, when n is more than 1 and m is more than 1, the metal bars are uniformly distributed among the iron-based superconducting single-core wires.
In the present invention, the material of the outer sheath is preferably one of titanium, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, cadmium, hafnium, tantalum, tungsten and lead, or any one of alloys of the above metals, more preferably stainless steel, monel, copper, tantalum, iron or hastelloy. The invention adopts the material with higher mechanical strength as the outer layer wrapping pipe, which applies high pressure to the superconducting core during cold working, and the work hardening is not easy to disappear, so that the superconducting core is still under the action of high pressure stress during heat treatment, and the density of the superconducting core is improved.
In the present invention, the thickness of the outer covering pipe is preferably 0.3 to 2mm, more preferably 0.5 to 1mm. In the present invention, the cross-sectional shape of the outer covering pipe is preferably regular hexagon, square or circle. In the present invention, the cross-sectional shape of the outer sheath pipe preferably coincides with the cross-sectional shape of the iron-based superconducting single core wire and metal bar.
The invention, before loading n iron-based superconductive single-core wires and m metal bars into the outer sheath tube, preferably further comprises: firstly, n iron-based superconducting single-core wires and m metal bars are put into a tundish sleeve for assembly, so that a primary complex is obtained; the primary complex is then encased in an outer sheath to give a final complex. The invention firstly loads the iron-based superconductive single-core wire rod and the metal bar into the tundish sleeve, processes the iron-based superconductive single-core wire rod and the metal bar to obtain the primary composite body, and then loads the primary composite body into the outer-layer casing sleeve.
In the present invention, the material of the tundish sleeve is preferably silver-tin alloy, silver-magnesium alloy or copper. In the present invention, the thickness of the tundish sleeve is preferably 0.3 to 3mm, more preferably 0.5 to 2mm.
In the invention, the assembly mode of the n iron-based superconducting single-core wires and the m metal bars in the tundish casing is preferably the same as the assembly mode of the n iron-based superconducting single-core wires and the m metal bars in the outer-layer casing, and is not repeated here.
After the final composite body is obtained, the final composite body is subjected to grooved rolling and heat treatment in sequence, and the iron-based superconducting composite wire rod is obtained. In the invention, the pass of the pass rolling is preferably a c-polygon, wherein c is equal to or greater than 3. In a specific embodiment of the present invention, the pass of the grooved roll is a regular triangle, square, regular hexagon or regular octagon. In the invention, when the pass of the pass rolling is square, the wire rod manufactured by using the pass is wound into a magnet, and the wire rod is not easy to slide due to the action of Lorentz force and the like; when the pass of the grooved rolling is regular hexagon or regular octagon, the cross section of the rolled wire rod is more approximate to a circle, and the magnet is easier to wind.
In the present invention, the grooved rolling temperature is preferably 20 to 900 ℃, more preferably 30 to 400 ℃; the grooved rolling is preferably multi-pass processing, and the processing passes are preferably 3-12 passes, more preferably 6-10 passes; the processing rate per pass is preferably 5 to 40%, more preferably 10 to 20%, still more preferably 15%.
The final cold working means of the final composite body is grooved rolling. At present, the final cold working means of forming the iron-based superconducting wire strip is generally drawing or flat roller rolling, the drawing applies isotropic force for contracting the wire rod towards the center, but the contraction force is smaller, so that the density of the superconducting core of the wire rod after final heat treatment is lower, and the Vickers hardness is less than 100HV; the flat roll rolling only provides axial pressure, and although the compactness and the texture can be improved, the wire rod is finally processed into a strip, and the purpose of preparing the wire rod cannot be achieved. The final cold working means adopted by the invention is grooved rolling, and a large isotropic compression force is provided in the process of working deformation; in addition, the material of the outer layer cladding sleeve is selected from metal with higher mechanical strength, the outer layer cladding sleeve is strongly contracted towards the center under the action of grooved rolling, and huge compressive stress is provided for the central superconducting core, so that the density of the superconducting core is greatly improved.
In the present invention, the temperature of the heat treatment is preferably 500 to 1400 ℃, more preferably 600 to 1000 ℃, still more preferably 650 to 850 ℃. In the present invention, the time of the heat treatment is preferably 0.1 to 24 hours, more preferably 0.5 to 18 hours, and still more preferably 6 to 12 hours. In the present invention, the heat treatment is preferably performed under an inert atmosphere or vacuum, particularly preferably an argon atmosphere, a nitrogen atmosphere or vacuum; the pressure of the system in the heat treatment process is preferably 10 -5 ～10 5 Pa, the pressure is preferably 10 when the heat treatment is carried out in an inert atmosphere 3 ～10 5 Pa, the pressure is preferably 10 when the heat treatment is performed under vacuum conditions -5 ～10 -2 Pa. In the present invention, the heat treatment functions to promote grain growth and increase connectivity between grains.
The invention also provides the iron-based superconducting composite wire prepared by the preparation method. In the invention, the iron-based superconducting composite wire comprises an outer layer sleeve, n iron-based superconducting single-core wires and m metal bars, wherein the n iron-based superconducting single-core wires and the m metal bars are arranged inside the outer layer sleeve. In the present invention, the cross-sectional shape of the iron-based superconducting composite wire is preferably a regular triangle, square, regular hexagon, or regular octagon. In the invention, the arrangement mode of the n iron-based superconducting single-core wires and the m metal bars in the outer-layer sheath tube is preferably as follows: when m=1, the metal bar is arranged at the center of the iron-based superconducting single-core wires, the iron-based superconducting single-core wires surround the metal bar along the circumferential direction, and when m is more than 1, the m metal bars are uniformly distributed in the iron-based superconducting single-core wires.
In the present invention, the iron-based superconducting composite wire preferably further includes a tundish sleeve, and particularly preferably: the iron-based superconducting composite wire comprises an outer layer wrapping sleeve, a middle wrapping sleeve arranged in the outer layer wrapping sleeve, n iron-based superconducting single-core wires and m metal bars arranged in the middle wrapping sleeve.
The technical solutions of the present invention will be clearly and completely described in the following in connection with the embodiments of the present invention. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
Preparing a silver-coated iron-based superconducting single-core wire;
the silver-coated iron-based superconducting single-core wire is plugged into a stainless steel tube to form a final composite;
machining the final composite body through grooved rolling, wherein the grooved rolling has hexagonal grooved, machining passes are 12 passes, and the machining rate of each pass is 5%;
placing the composite wire rod subjected to grooved rolling into a vacuum furnace, wherein the vacuum degree is 10 -5 Pa, heating to 500 ℃, and preserving heat for 24 hours to obtain the iron-based superconducting single-core composite wire.
The cross-sectional view of the iron-based superconducting single core composite wire rod prepared in this example is shown in fig. 1 (a). Through test, the vickers hardness of the superconducting core in the iron-based superconducting single-core composite wire is 280HV, the critical current density is 2.1 multiplied by 10 under the conditions of 4.2K and 10T 4 A/cm 2 。
Example 2
Preparing a silver-coated iron-based superconducting single-core wire;
dividing the silver-coated iron-based superconducting single-core wire into 7 sections, and then plugging 7 silver-coated iron-based superconducting single-core wires into a silver-tin alloy coating sleeve, and processing the silver-coated iron-based superconducting single-core wire into a primary complex;
the primary complex is plugged into a hastelloy tube to form a final complex;
the final composite body is processed into a composite wire rod through grooved rolling, the grooved rolling has regular octagons, the processing pass is 10 passes, and the pass processing rate is 10%;
carrying out high-temperature heat treatment on the composite wire rod subjected to grooved rolling, wherein the heat treatment atmosphere is argon, and the pressure is 10 3 Pa, the heat treatment temperature is 700 ℃, and the heat preservation is carried out for 12 hours, thus obtaining the seven-core iron-based superconducting composite wire.
The cross-sectional view of the seven-core iron-based superconducting composite wire prepared in this example is shown in (b) of FIG. 1, the Vickers hardness of the superconducting core is up to 400HV, the density is up to 100% as shown in FIG. 3, the critical current density at 4.2K is as shown in FIG. 2, and the critical current density at 10T is up to 1.9X10 4 A/cm 2 。
Example 3
Preparing a silver-tin alloy coated iron-based superconducting single-core wire, so that the cross section of the wire is regular hexagon;
dividing the iron-based superconducting single-core wire into 6 sections, then, plugging 6 iron-based superconducting single-core wires and 1 Monel alloy rod with a regular hexagon cross section into a Monel alloy sheath pipe with a hexagon cross section, wherein the Monel alloy rod is arranged in the center of the 6 iron-based superconducting single-core wires, and the 6 iron-based superconducting single-core wires surround the Monel alloy rod along the circumferential direction to form a final composite body, and the schematic diagram of the final composite body is shown in (c) in fig. 1;
the final composite body is processed into a composite wire rod through grooved rolling, the grooved rolling has regular hexagon, the processing pass is 8 passes, and the pass processing rate is 15%;
carrying out high-temperature heat treatment on the composite wire rod subjected to grooved rolling, wherein the heat treatment atmosphere is argon, and the pressure is 10 4 Pa, the heat treatment temperature is 850 ℃, and the heat preservation is carried out for 0.5 hour, thus obtaining the six-core iron-based superconducting composite wire.
The six-core iron-based superconducting composite wire prepared by the embodiment adds the Monel alloy bar with high mechanical strength in the center, and the Monel alloy bar and the outer layer cladding sleeve are used for feeding the silver-tin alloy cladding sleeve and the superconducting core in the grooved rolling processThe method is characterized in that the method performs local axial extrusion, and simultaneously improves the texture degree and the density, thereby greatly improving the critical current density, and the critical current density under 4.2K and 10T reaches 1.2 multiplied by 10 5 A/cm 2 The method comprises the steps of carrying out a first treatment on the surface of the The Vickers hardness is 350HV.
Example 4
Preparing a silver-manganese alloy coated iron-based superconducting single-core wire, so that the cross section of the wire is square;
dividing the iron-based superconducting single-core wire into 4 sections, and then plugging the 4 iron-based superconducting single-core wires and 1 copper rod with square cross section into an iron-clad square tube, wherein the copper rod is arranged at the center of the 4 iron-based superconducting single-core wires to form a final composite body, and the schematic diagram of the final composite body is shown in (d) in fig. 1;
the final composite body is processed into a composite wire rod through grooved rolling, the grooved rolling has square grooved, the processing pass is 6 passes, and the pass processing rate is 20%;
carrying out high-temperature heat treatment on the composite wire rod subjected to grooved rolling, wherein the heat treatment atmosphere is vacuum, and the pressure is 10 -3 Pa, the heat treatment temperature is 650 ℃, and the heat preservation is carried out for 6 hours, thus obtaining the four-core iron-based superconducting composite wire.
The four-core iron-based superconducting composite wire prepared by the embodiment is contracted towards the center by the outer square iron sheath in the grooved rolling process, and is extruded with the center square copper rod in a local axial direction together with the superconducting core, so that a texture is formed in the superconducting core. Through test, the four-core iron-based superconducting composite wire has the hardness of 280HV, and critical current density of 1X 10 under 4.2K and 10T 5 A/cm 2 。
Example 5
Preparing a silver-magnesium alloy coated iron-based superconducting single-core wire;
dividing the iron-based superconducting single-core wire into 18 sections, and then plugging 18 iron-based superconducting single-core wires and a copper rod into a silver-magnesium alloy sleeve, and processing the silver-magnesium alloy sleeve into a primary composite, wherein the copper rod is arranged in the center of the 18 iron-based superconducting single-core wires;
the primary complex is plugged into a copper pipe to form a final complex;
the final composite body is processed into a composite wire rod through grooved rolling, the grooved rolling has rectangular grooved, the processing pass is 5 passes, and the pass processing rate is 30%;
carrying out high-temperature heat treatment on the composite wire rod subjected to grooved rolling, wherein the heat treatment atmosphere is vacuum, and the pressure is 10 -2 Pa, the heat treatment temperature is 600 ℃, and the heat preservation is carried out for 18 hours, thus obtaining the 18-core iron-based superconducting composite wire.
The cross section of the 18-core iron-based superconducting composite wire rod prepared by the embodiment is rectangular, gaps among the wire rods can be effectively reduced when a magnet is wound, and meanwhile wire rod torsion is effectively prevented when the magnet is wound. The critical current density of the wire superconducting core reaches 5 multiplied by 10 under the condition of 4.2K and 10T 4 A/cm 2 The method comprises the steps of carrying out a first treatment on the surface of the The Vickers hardness was 300HV.
Example 6
Preparing a silver-tin alloy coated iron-based superconducting single-core wire;
the iron-based superconducting single-core wire is plugged into a tantalum tube to form a final composite;
machining the final composite body through grooved rolling, wherein the grooved of the grooved rolling is of a regular triangle, the machining passes are 3 passes, and the machining rate of each pass is 40%;
carrying out high-temperature heat treatment on the composite wire rod subjected to grooved rolling, wherein the atmosphere is nitrogen and the pressure is 10 5 Pa, heat treatment temperature is 1000 ℃, and heat preservation is carried out for 0.1 hour, thus obtaining the iron-based superconductive single-core composite wire.
Through tests, the superconductive core Vickers hardness of the iron-based superconductive single-core composite wire rod prepared in the embodiment is 200HV, and the critical current density reaches 1.1 multiplied by 10 under the conditions of 4.2K and 10T 4 A/cm 2 。
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (6)
1. The preparation method of the iron-based superconducting composite wire is characterized by comprising the following steps of:
packaging n iron-based superconducting single-core wires and m metal bars into an outer-layer packaging sleeve for assembly to obtain a final-stage complex; wherein n is more than or equal to 1, and m is more than 0;
sequentially carrying out grooved rolling and heat treatment on the final composite body to obtain an iron-based superconducting composite wire rod;
the sheathing material of the iron-based superconducting single-core wire is silver or silver alloy; the metal bar is made of nickel, nickel alloy, copper alloy, silver alloy, hastelloy or stainless steel; the grooved rolling is multi-pass processing, the processing passes are 3-12, and the processing rate of each pass is 5-40%;
the temperature of the heat treatment is 500-1400 ℃, the heat treatment is carried out under inert atmosphere or vacuum condition, and the pressure is 10 -5 ～10 4 Pa；
The material of the iron-based superconductor precursor powder in the iron-based superconducting single-core wire is Ba 1-x K x Fe 2 As 2 、Sr 1-x K x Fe 2 As 2 、BaFe 2-x Co x As 2 、SmFeAsO 1-x F x Or CaKFE 4 As 4 。
2. The method of manufacturing according to claim 1, further comprising, before loading the n iron-based superconducting single core wires and the m metal rods into the outer sheath: firstly, n iron-based superconducting single-core wires and m metal bars are put into a tundish sleeve for assembly, so that a primary complex is obtained; the primary complex is then encased in an outer sheath to give a final complex.
3. The method according to claim 1 or 2, wherein the material of the outer sheath is one of titanium, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, cadmium, hafnium, tantalum, tungsten, and lead, or any one of alloys of the above metals.
4. The method according to claim 3, wherein the outer sheath is made of stainless steel, monel, copper, tantalum, iron or hastelloy.
5. The method according to claim 1 or 2, wherein when n >1, m=1, the iron-based superconducting single core wire and the metal bar are assembled in the following manner: the metal bar is arranged at the centers of the iron-based superconducting single-core wires, and the iron-based superconducting single-core wires surround the metal bar along the circumferential direction.
6. The method of claim 1 or 2, wherein the grooved hole is c-sided, where c is 3 or more.
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| JP2003331660A (en) * | 2002-05-08 | 2003-11-21 | Hitachi Ltd | Metal-sheathed superconductor wire, superconducting coil, and its manufacturing method |
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| CN105869781A (en) * | 2016-06-29 | 2016-08-17 | 西北有色金属研究院 | Preparation method of FeSe-based superconduction wire |
| CN106601366A (en) * | 2016-12-14 | 2017-04-26 | 中国科学院电工研究所 | Manufacturing method of 122 type iron-based compound superconducting wire or belt material |
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Patent Citations (4)
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|---|---|---|---|---|
| JP2003331660A (en) * | 2002-05-08 | 2003-11-21 | Hitachi Ltd | Metal-sheathed superconductor wire, superconducting coil, and its manufacturing method |
| CN101859612A (en) * | 2010-05-24 | 2010-10-13 | 西部超导材料科技有限公司 | Preparation method of CuNb composite pipe for high-field Nb3Sn wire material |
| CN105869781A (en) * | 2016-06-29 | 2016-08-17 | 西北有色金属研究院 | Preparation method of FeSe-based superconduction wire |
| CN106601366A (en) * | 2016-12-14 | 2017-04-26 | 中国科学院电工研究所 | Manufacturing method of 122 type iron-based compound superconducting wire or belt material |
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