A high-performance MgB2 superconducting wire and its preparation method

Abstract

The application belongs to the technical field of superconducting materials, and discloses a high-performance MgB2 superconducting wire and a preparation method thereof. The method comprises the following steps: firstly, uniformly mixing nano-Mg alloy powder and B powder in an inert gas atmosphere according to an atomic number ratio of Mg:B=1:2; secondly, compounding a high-purity Nb rod, a CuNi alloy tube and an oxygen-free Cu tube into an Nb / CuNi / Cu alloy rod, processing deep holes, and then making a single-core wire by loading the mixed powder; thirdly, assembling the single-core wire into a Monel alloy tube, processing into a multi-core composite wire, and obtaining the high-performance MgB2 superconducting wire through high-temperature phase formation heat treatment. The metal elements in the nano-Mg alloy powder can generate metal borides, and the CuNi alloy has both constraint and barrier effects, so that the MgB2 grains of the wire are refined, the connectivity between the grains is improved, and the current-carrying performance is improved.

Description

Technical Field

[0001] This invention belongs to the field of superconducting materials technology, and relates to a high-performance MgB2 superconducting wire and its preparation method. Background Technology

[0002] MgB2 superconducting materials, as simple binary intermetallic compounds, offer advantages over copper oxide high-temperature superconductors (such as REBa2Cu3O). 7-x Bi2Sr2Ca2Cu3O 7-x The weak connections in the grain boundary regions of MgB2 have almost no negative impact on superconducting performance. Moreover, the raw materials required for its preparation, such as Mg powder and B powder, are inexpensive and abundant. In addition, the practical application of MgB2 superconducting wires / tapes adopts mature and simple powder packing technology, which gives this type of wire an irreplaceable advantage in engineering applications such as superconducting energy storage, superconducting cables, and superconducting magnetic resonance imaging in the 20K~30K temperature range. It has become a research and application hotspot in the field of superconducting materials.

[0003] Currently, the mainstream fabrication technologies for commercial MgB2 wires / ribbons mainly include ex-suitPIT, in-suitPIT, and CTFF (Continuous In-Situ Powder Filament). While ex-suitPIT-prepared MgB2 superconducting wires can be directly used in practical engineering applications, they suffer from low intergranular coupling, making it difficult to achieve high superconducting current-carrying performance. In-suitPIT, although improving intergranular coupling, presents pores in the core wire that hinder the solid-phase diffusion reaction between Mg and B powders, leading to the formation of numerous impurity phases between MgB2 grains and limiting the effective transport of superconducting current between grains.

[0004] Superconducting current-carrying capacity and grain connectivity are core indicators for the practical application of MgB2 superconducting wires. The aforementioned defects in existing preparation techniques severely restrict the application and promotion of MgB2 superconducting wires in related engineering fields. With the increasing demand for superconducting technology in energy storage, medical imaging, and power transmission, the performance requirements for MgB2 superconducting wires are becoming increasingly stringent. Therefore, developing a preparation method that can effectively improve the grain connectivity and current-carrying capacity of MgB2 and solve the bottlenecks of existing technologies is of significant practical importance and urgency for promoting the industrial application of MgB2 superconducting materials and expanding their engineering application boundaries. Summary of the Invention

[0005] This invention aims to address the core defects in existing MgB2 superconducting wire fabrication technologies, specifically: wires prepared by the pre-situ powder packing method exhibit low intergranular coupling in MgB2, resulting in insufficient superconducting current-carrying capacity; while the in-situ powder packing method can improve intergranular coupling, the pores in the core wire hinder the solid-phase diffusion reaction between Mg and B powders, leading to an increase in impurities between grains and limiting superconducting current transport. Furthermore, existing fabrication processes lack effective barrier mechanisms, easily causing Mg-based powder to spill into the matrix, further affecting the wire's performance stability. The core objective of this invention is to provide a high-performance MgB2 superconducting wire and its fabrication method that can significantly improve the intergranular connectivity and superconducting current-carrying capacity of MgB2 and effectively suppress Mg-based powder spillage.

[0006] To achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing high-performance MgB2 superconducting wire, comprising the following steps:

[0008] S1. Mix nano-Mg alloy powder and B powder evenly in an inert gas atmosphere. The mass of nano-Mg alloy powder and B powder is calculated according to the atomic ratio Mg:B = 1:2.

[0009] S2. Process Nb rods, CuNi alloy tubes and oxygen-free Cu tubes into Nb / CuNi / Cu alloy rods;

[0010] S3. A deep hole is machined in the central region of the Nb / CuNi / Cu alloy rod;

[0011] S4. In an inert gas atmosphere, the mixed powder of S1 is loaded into the central deep hole of the Nb / CuNi / Cu alloy rod, and then processed into a single-core wire using a cold plastic forming method.

[0012] S5. Cut and clean the single-core wire to a fixed length, and then assemble them closely into a Monel alloy tube for further processing into a multi-core composite wire.

[0013] S6. The high-performance MgB2 superconducting wire is obtained by processing the multi-core composite wire.

[0014] Furthermore, in step S1 of the above preparation method, the nano-Mg alloy powder is selected from one of MgAg, MgAl, MgTi, MgZn, and MgAlZn.

[0015] Furthermore, in step S1 of the above preparation method, the average particle size of the nano-Mg alloy powder is 700~900nm, and the mass fraction of other metal elements in the powder, excluding Mg, is 5~30%.

[0016] The average particle size of powder B is 600~800nm, and the purity is 99.5~99.9%.

[0017] Furthermore, in step S2 of the above preparation method, the Nb rod has a purity of 99.5-99.9% and is in an annealed state;

[0018] The mass fraction of Ni element in CuNi alloy pipes is 5-70%;

[0019] The oxygen-free Cu tubes have a purity of 99.95%~99.99% and are in the annealed state;

[0020] The processing method for preparing Nb / CuNi / Cu alloy rods is mechanical hot extrusion.

[0021] Furthermore, in step S3 of the above preparation method, the method for machining deep holes is deep hole drilling.

[0022] Furthermore, in step S4 of the above preparation method, the cold plastic forming method is at least one of drawing, rolling, or forging.

[0023] Furthermore, in step S5 of the above preparation method, the processing technology for preparing the multi-core composite wire is plastic processing.

[0024] Furthermore, in step S5 of the above preparation method, the size of the multi-core composite wire is 1~2 mm.

[0025] Furthermore, in step S6 of the above preparation method, the processing method of the multi-core composite wire is high-temperature phase-forming heat treatment; the conditions are 520~880℃, 5~15h.

[0026] Secondly, the present invention claims protection for a high-performance MgB2 superconducting wire, which is prepared by the above-described preparation method.

[0027] Compared with the prior art, the present invention has the following significant advantages:

[0028] Significantly improved grain connectivity and current carrying capacity: This invention uses nano-Mg alloy powder (such as MgAg, MgAl, MgZn, MgTi, MgAlZn, etc.) as the Mg source. During the solid-phase diffusion of Mg and B to form MgB2, the metal elements in the alloy will enter the grain boundary region in situ and generate metal borides. These metal borides can effectively refine the MgB2 grains (the final grain size can reach 90nm) and significantly improve the connectivity between grains. This fundamentally solves the problems of poor grain coupling and obstructed superconducting current transport in the prior art, and greatly improves the superconducting current carrying capacity of the wire.

[0029] Effective suppression of Mg-based powder spillage: By introducing CuNi alloy into the core wire metal matrix, its high strength can provide good constraint for the plastic deformation of powder, ensuring the forming stability of powder during processing; at the same time, the alloying characteristics of CuNi alloy can more effectively block the spillage of nano Mg alloy powder into the oxygen-free Cu matrix, avoiding performance degradation caused by powder spillage and improving the stability and consistency of wire performance.

[0030] The invention boasts strong process compatibility and outstanding practicality: Based on a mature powder-packing technology framework, this invention optimizes the process steps, ensuring clear and controllable procedures. The raw materials used are abundant and cost-effective, and the preparation process requires no complex or specialized equipment, facilitating large-scale production. The prepared multi-core MgB2 superconducting wire exhibits significant advantages in engineering applications such as superconducting energy storage, superconducting cables, and superconducting magnetic resonance imaging in the 20–30 K temperature range, effectively promoting the practical application and industrialization of MgB2 superconducting materials. Attached Figure Description

[0031] Figure 1 This describes the microstructure of the MgB2 wire superconducting core prepared in Example 1 of this invention.

[0032] Figure 2 This is the microstructure of the MgB2 wire superconducting core prepared in Example 2 of the present invention.

[0033] Figure 3 This is the microstructure of the MgB2 wire superconducting core prepared in Example 3 of the present invention.

[0034] Figure 4 This is the microstructure of the MgB2 wire superconducting core prepared in Comparative Example 1 of this invention.

[0035] Figure 5 The critical engineering current density of the MgB2 wire superconducting core prepared in each embodiment and Comparative Example 1 is ( It is The curve of change with magnetic field strength. Detailed Implementation

[0036] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a method for preparing high-performance MgB2 superconducting wires based on nano-MgAg alloy powder. The specific steps are as follows:

[0039] S1. Raw material mixing: In a glove box protected by circulating argon gas with a purity of 99.999%, nano-MgAg alloy powder and B powder are mixed evenly at an atomic ratio of Mg:B = 1:2; wherein, the purity of B powder is 99.9% and the average particle size is 600nm; the average particle size of nano-MgAg alloy powder is 800nm, and the mass fraction of Ag element in the alloy is 30%.

[0040] S2. Composite rod preparation: An annealed Nb rod with a purity of 99.9% is inserted into a CuNi alloy tube, and then the assembled Nb rod and CuNi alloy tube are inserted together into an annealed oxygen-free Cu tube with a purity of 99.99%. The Nb / CuNi / Cu composite rod is processed by mechanical hot extrusion. The mass fraction of Ni element in the CuNi alloy tube is 55%.

[0041] S3. Hole processing: The above-mentioned Nb / CuNi / Cu composite rod is drawn into a diameter of [missing information]. After obtaining a 30mm single core rod, a hole with a diameter of [missing information] is machined in the central region of the composite rod using deep hole drilling. 15mm through hole.

[0042] S4. Single-core wire preparation: In a glove box protected by flowing argon gas with a purity of 99.999%, the uniformly mixed powder from S1 is loaded into the central through-hole of the Nb / CuNi / Cu composite rod, and then drawn to form a single wire with a diameter of [missing information]. A 6mm single-core wire was then cut to length and surface-cleaned.

[0043] S5. Preparation of multi-core composite wire: After the treated single-core wires are closely packed and assembled, they are put into a Monel alloy tube and then drawn to prepare a multi-core composite wire with a diameter of 1mm.

[0044] S6. High-temperature phase formation heat treatment: The above multi-core composite wire is placed in a vacuum environment and kept at 520℃ for 15 hours to complete the high-temperature phase formation heat treatment, and finally high-performance MgB2 superconducting wire is obtained.

[0045] Figure 1 This image shows the microstructure of the superconducting core wire of the MgB2 superconducting wire prepared in this embodiment. Figure 1 It can be seen that the superconducting core wire prepared by the method of this embodiment has a uniform distribution of MgB2 grains with a grain size of up to 90 nm, and the grains are closely connected with each other without obvious pores or impurities, which fully demonstrates the advantages of the method of this invention in improving the connectivity between grains.

[0046] Example 2

[0047] This embodiment provides a method for preparing high-performance MgB2 superconducting wires based on nano-MgAl alloy powder. The specific steps are as follows:

[0048] S1. Raw material mixing: In a glove box protected by circulating argon gas with a purity of 99.999%, nano-MgAl alloy powder and B powder are mixed evenly at an atomic ratio of Mg:B = 1:2; wherein, the purity of B powder is 99.9% and the average particle size is 700nm, the average particle size of nano-MgAl alloy powder is 800nm, and the mass fraction of Al element in the alloy is 20%.

[0049] S2. Composite rod preparation: An annealed Nb rod with a purity of 99.9% is inserted into a CuNi alloy tube, and then the assembled Nb rod and CuNi alloy tube are inserted together into an annealed oxygen-free Cu tube with a purity of 99.99%. The Nb / CuNi / Cu composite alloy rod is processed by mechanical hot extrusion. The mass fraction of Ni element in the CuNi alloy tube is 55%.

[0050] S3. Hole processing: The above-mentioned Nb / CuNi / Cu composite rod is drawn into a diameter of [missing information]. After obtaining a 30mm single core rod, a hole with a diameter of [missing information] is machined in the central region of the composite rod using deep hole drilling. 15mm through hole.

[0051] S4. Single-core wire preparation: In a glove box protected by flowing argon gas with a purity of 99.999%, the uniformly mixed powder from S1 is loaded into the central through-hole of the Nb / CuNi / Cu composite rod, and then drawn to form a single wire with a diameter of [missing information]. A 6mm single-core wire was then cut to length and surface-cleaned.

[0052] S5. Preparation of multi-core composite wire: After the treated single-core wires are closely packed and assembled, they are put into a Monel alloy tube and then drawn to prepare a multi-core composite wire with a diameter of 1mm.

[0053] S6. High-temperature phase formation heat treatment: The above multi-core composite wire is placed in a vacuum environment and kept at 680℃ for 10 hours to complete the high-temperature phase formation heat treatment, and finally high-performance MgB2 superconducting wire is obtained.

[0054] like Figure 2 The figure shows the microstructure of the superconducting core wire of the MgB2 superconducting wire prepared in this embodiment. As can be seen from the figure, the MgB2 grains in the superconducting core wire prepared in this embodiment are effectively refined, the grain boundary bonding is good, and there are no obvious pores or impurity phases interfering with the process. This fully verifies that using nano-MgAl alloy powder as the Mg source can significantly improve the connectivity between MgB2 grains and ensure the superconducting current-carrying performance of the wire.

[0055] Example 3

[0056] This embodiment provides a method for preparing high-performance MgB2 superconducting wires based on nano-MgTi alloy powder. The specific steps are as follows:

[0057] S1. Raw material mixing: In a glove box protected by circulating argon gas with a purity of 99.999%, nano-MgTi alloy powder and B powder are mixed evenly at an atomic ratio of Mg:B = 1:2; wherein, the purity of B powder is 99.9% and the average particle size is 800nm, the average particle size of nano-MgTi alloy powder is 800nm, and the mass fraction of Ti element in the alloy is 10%.

[0058] S2. Composite rod preparation: An annealed Nb rod with a purity of 99.9% is inserted into a CuNi alloy tube, and then the assembled Nb rod and CuNi alloy tube are inserted together into an annealed oxygen-free Cu tube with a purity of 99.99%. The Nb / CuNi / Cu composite alloy rod is processed by mechanical hot extrusion. The mass fraction of Ni element in the CuNi alloy tube is 55%.

[0059] S3. Hole processing: The above-mentioned Nb / CuNi / Cu composite rod is drawn into a diameter of [missing information]. After obtaining a 30mm single core rod, a hole with a diameter of [missing information] is machined in the central region of the composite rod using deep hole drilling. 15mm through hole.

[0060] S4. Single-core wire preparation: In a glove box protected by flowing argon gas with a purity of 99.999%, the uniformly mixed powder from S1 is loaded into the central through-hole of the Nb / CuNi / Cu composite rod, and then drawn to form a single wire with a diameter of [missing information]. A 6mm single-core wire was then cut to length and surface-cleaned.

[0061] S5. Preparation of multi-core composite wire: After the treated single-core wires are closely packed and assembled, they are put into a Monel alloy tube and then drawn to prepare a multi-core composite wire with a diameter of 1mm.

[0062] S6. High-temperature phase formation heat treatment: The above multi-core composite wire is placed in a vacuum environment and kept at 880℃ for 5 hours to complete the high-temperature phase formation heat treatment, and finally high-performance MgB2 superconducting wire is obtained.

[0063] like Figure 3The figure shows the microstructure of the superconducting core wire of the MgB2 superconducting wire prepared in this embodiment. As can be seen from the figure, the MgB2 grains inside the superconducting core wire prepared in this embodiment are significantly refined, with excellent inter-grain connectivity and no obvious pores or impurities. This fully demonstrates that using nano-MgTi alloy powder as the Mg source, combined with the corresponding heat treatment process, can effectively optimize the MgB2 grain structure and ensure the high-performance superconducting properties of the wire.

[0064] Comparative Example 1

[0065] This comparative example provides a conventional method for preparing MgB2 superconducting wires.

[0066] The preparation steps of this comparative example are the same as those of Example 3, except that in S1, Mg powder (purity of 99.9% and particle size of 30μm) is directly mixed with B powder.

[0067] Figure 4 This image shows the microstructure of the superconducting core wire of the MgB2 superconducting wire prepared in this comparative embodiment. As can be seen from the image, the superconducting core wire prepared using conventional Mg powder as the Mg source exhibits uneven MgB2 grain size, loose grain boundary bonding, and obvious pores and impurities. These defects result in poor inter-grain connectivity, hindering superconducting current transport. This fully demonstrates the limitations of conventional preparation methods in improving wire performance, forming a stark contrast with the high-performance MgB2 superconducting wires prepared in the embodiments of this invention.

[0068] Example 4

[0069] This embodiment provides a comparison of the performance of MgB2 superconducting wires in Examples 1-3 and Comparative Example 1.

[0070] To verify the performance improvement effect of the preparation method of the present invention on MgB2 superconducting wires, the wires prepared in Examples 1-3 and Comparative Example 1 were used as test samples, and the critical engineering current density was tested. It is Comparative tests were conducted, and performance differences were analyzed in conjunction with microstructural characteristics.

[0071] I. Experimental Methods

[0072] 1. Test Sample

[0073] The final MgB2 superconducting wires prepared in Examples 1-3 and Comparative Example 1 were selected. All samples were multi-core composite wires with a diameter of 1 mm. Standard samples with a length of 100 mm (for superconducting performance testing) and cross-sectional samples with a length of 5 mm (for microstructure testing) were cut. The surfaces were cleaned with anhydrous ethanol to remove oil stains and ensure good contact for testing. Before testing, all samples were kept in their original heat treatment state during the preparation process without any additional secondary treatment.

[0074] 2. Test Indicators

[0075] Critical engineering current density It is (Unit: A / mm) 2 The core indicator for evaluating the superconducting current-carrying capacity of wires is defined as the ratio of the maximum superconducting current that the wire can stably carry under a specific temperature and magnetic field to the total cross-sectional area.

[0076] Microscopic morphological characteristics: Reflect the internal structural quality of the superconducting wire core, including grain size (nm), porosity (%), impurity phase content (%), and grain boundary bonding state, which are the structural basis for explaining the differences in current carrying performance.

[0077] 3. Test conditions

[0078] Superconducting performance testing conditions: test temperature 4.2K, magnetic field range 2~6T, current criterion: adopting the industry standard criterion, that is, the current when the voltage drop reaches 1μV / cm is the critical current. Ic , It is = Ic / S ( S Total cross-sectional area of ​​the wire, unit: mm 2 ).

[0079] Microscopic morphology testing conditions: Observation area: central region of the core wire cross-section, magnification: 5000x.

[0080] 4. Testing Methods

[0081] Superconducting performance testing: The four-lead method (to eliminate lead resistance interference) was used. A constant DC current was applied to both ends of the sample, and the current was gradually increased until the critical current criterion was reached. The current was recorded simultaneously under different magnetic fields. Ic Calculations yielded It is Microstructure characterization: After mounting, grinding, and polishing, the cross-sectional samples were coated with an ion sputtering film (5 nm thick) to avoid the charging effect. The microstructure was observed by FESEM. Using ImageJ software, the grain size was statistically analyzed: 50 grains were randomly selected and the average value was taken. Porosity: the proportion of the pore area to the total area of ​​the observation area; Impurity phase content: the proportion of the impurity phase area to the total area of ​​the observation area, to qualitatively describe the grain boundary bonding state.

[0082] II. Experimental Results

[0083] 1. Critical engineering current density It is Test Results

[0084] Table 1. Wires of each embodiment and comparative example It is value

[0085]

[0086] It isThe curve of change with magnetic field strength is as follows Figure 5 As shown, the MgB2 superconducting wires prepared in Examples 1-3 exhibit [the following characteristics]. It is The values ​​in Example 3 were significantly higher than those in Comparative Example 1 across the entire magnetic field test range (2~6T), and the performance advantage was more pronounced with higher magnetic field strength: under low magnetic field (2T), the performance advantage of Example 3 was significantly higher. It is Reaching 1809A / mm 2 This is Comparative Example 1 (1197A / mm) 2 1.5 times that of ) under a medium magnetic field (3T), Example 3 It is 904A / mm 2 This is Comparative Example 1 (575A / mm) 2 1.6 times that of Example 3; under a high magnetic field (6T), It is 113A / mm 2 This is comparative example 1 (59A / mm) 2 1.9 times that of ).

[0087] 2. Microstructure characterization results

[0088] Table 2. Microstructure of the wires in each embodiment and comparative example

[0089]

[0090] Examples 1-3 use nano-sized Mg alloy powder (MgAg, MgAl, MgTi) as the Mg source. During the high-temperature phase formation process, the Ag, Al, and Ti metal elements in the alloy will form metal borides (such as AgB2, AlB2, TiB2) in situ. These borides, on the one hand, refine the grains, controlling the MgB2 grain size to 70-120 nm (much smaller than the 700-1000 nm of Comparative Example 1); on the other hand, they act as grain boundary bridging phases, significantly improving the connectivity between grains, eliminating grain boundary voids, and ensuring efficient superconducting current transport. Comparative Example 1 uses conventional micron-sized Mg powder, which has insufficient solid-phase diffusion reaction with B powder, resulting in a large number of pores and impurities inside the core wire, and loose grain boundary bonding, causing the superconducting current to be blocked at the grain boundaries. It is A significant decrease.

[0091] Performance differences of different nano-Mg alloy powders: Example 3 (MgTi) It is The best result was achieved in Example 2 (MgAl) and Example 1 (MgAg). This is related to the higher stability of TiB2 boride formed by Ti element and its more significant effect on grain refinement and grain boundary strengthening, indicating the regulatory effect of alloy element type on wire performance.

[0092] In summary, this invention successfully prepared high-performance MgB2 superconducting wires by using nano-Mg alloy powder as the Mg source, combined with the barrier and constraint effects of the Nb / CuNi / Cu composite matrix. Compared to conventional preparation methods (Comparative Example 1), the critical engineering current density of the wires produced by this invention is significantly higher. It is The 1.5-1.9-fold increase in current-carrying capacity at a magnetic field of 2-6T and a temperature of 4.2K is attributed to the significant refinement of MgB2 grains, improved inter-grain connectivity, and reduction of internal defects (pores, impurities) in the core wire. The significant advantages of this invention's preparation method in enhancing the current-carrying capacity of MgB2 superconducting wires lay the performance and structural foundation for their application in engineering fields such as superconducting energy storage, superconducting cables, and superconducting magnetic resonance imaging.

[0093] The embodiments described above are only some, not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art through related deductions and substitutions based on the inventive concept, without inventive effort, are within the scope of protection of the present invention.

Claims

1. A method for preparing high-performance MgB2 superconducting wire, characterized in that, Includes the following steps: S1. Nano-Mg alloy powder and B powder are mixed uniformly in an inert gas atmosphere, with the mass of nano-Mg alloy powder and B powder calculated according to the atomic ratio of Mg:B = 1:2; the nano-Mg alloy powder is selected from one of MgAg, MgAl, MgTi, MgZn, and MgAlZn, the average particle size of the nano-Mg alloy powder is 700~900nm, and the mass fraction of other metal elements in the powder, excluding Mg, is 5~30%; the average particle size of the B powder is 600~800nm, and the purity is 99.5~99.9%; S2. Nb rods, CuNi alloy tubes, and oxygen-free Cu tubes are processed into Nb / CuNi / Cu alloy rods; wherein the Nb rods have a purity of 99.5~99.9% and are in the annealed state; the mass fraction of Ni element in the CuNi alloy tubes is 5~70%; the purity of the oxygen-free Cu tubes is 99.95~99.99% and are in the annealed state; the processing method for preparing Nb / CuNi / Cu alloy rods is mechanical hot extrusion; S3. A deep hole is machined in the central region of the Nb / CuNi / Cu alloy rod; S4. In an inert gas atmosphere, the mixed powder of S1 is loaded into the central deep hole of the Nb / CuNi / Cu alloy rod, and then processed into a single-core wire using a cold plastic forming method. S5. Cut and clean the single-core wire to a fixed length, and then assemble them closely into a Monel alloy tube for further processing into a multi-core composite wire. S6. The high-performance MgB2 superconducting wire is obtained by subjecting the multi-core composite wire to high-temperature phase-forming heat treatment in a vacuum environment. The conditions for the high-temperature phase-forming heat treatment are 520~880℃ for 5~15h.

2. The preparation method according to claim 1, characterized in that, In S3, the method for machining deep holes is deep hole drilling.

3. The preparation method according to claim 1, characterized in that, In S4, the cold plastic forming method is at least one of drawing, rolling or forging.

4. The preparation method according to claim 1, characterized in that, In S5, the processing technology for preparing the multi-core composite wire is plastic processing.

5. The preparation method according to claim 1, characterized in that, In S5, the size of the multi-core composite wire is 1~2mm.

6. A high-performance MgB2 superconducting wire, characterized in that, The high-performance MgB2 superconducting wire is prepared by the preparation method described in any one of claims 1 to 5.

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