An optimized tin source distributed Nb3Sn wire and preparation method thereof

Abstract

The invention belongs to the technical field of superconducting wires and discloses an optimized tin source distributed Nb 3 Sn wire and its preparation method. The present invention introduces Ti element into CuNb composite rod, and Ti element accounts for 1.0~3.0at.% of Nb element, avoiding Ti in the wire drawing process. 6 Sn 5 The wire breakage problem caused by hard compounds is solved, and the maximum wire length of the wire is significantly improved. In addition, the invention adds metal elements such as Zn and Ni to Sn, which can accelerate the mutual diffusion of Sn and Cu during heat treatment and promote the uniform stoichiometric ratio of Nb 3 The formation of Sn phase can effectively increase the Nb 3 Critical current density of Sn wire.

Description

Technical Field

[0001] The invention belongs to the technical field of superconducting wires and relates to an optimized tin source distributed Nb 3 Sn wire and preparation method thereof. Background Art

[0002] High-field superconducting magnets play a very important role in many large-scale physics experiments, especially in particle colliders and fusion confinement devices such as the Large Hadron Collider (LHC) and the International Thermonuclear Experimental Reactor (ITER). 3 Sn is the most commonly used high-field superconductor in these applications. 3 Sn production methods mainly include bronze method, internal tin method and powder tube method. 3 As a new process route, Sn wire can effectively increase the Nb content and critical current density of the wire, while reducing the size of the Nb module, shortening the diffusion distance of the tin source, and reducing wire loss. 3 Sn wire preparation method, tin source distributed Nb 3 Sn wire also eliminates the drilling step in the wire processing process, effectively shortening the wire processing cycle and reducing the wire processing cost.

[0003] In the internal tin method Nb 3 During the preparation of Sn wire, Ti element is usually introduced. The addition of Ti element can increase the rate of Sn-Cu interdiffusion and promote Nb 3 The formation of Sn phase. During the preparation process, Ti is usually added to Sn. However, the Ti in SnTi alloy 6 Sn 5 The plastic deformation ability of cemented carbide blocks is poor during the wire drawing process, which leads to wire breakage under small drawing conditions. During the medium temperature stage of the final heat treatment of the wire, the Ti element in the SnTi alloy will be enriched around the Nb module, hindering the diffusion of Sn to the Nb core wire, thereby affecting the critical current density of the final wire. This requires the existing tin source distributed Nb 3 Sn wire is further improved to solve the above problems. Summary of the invention

[0004] In order to improve the distribution of Nb 3 Tensile properties and critical current density of Sn wire, solve the existing tin source distributed Nb 3 The invention provides an optimized tin source distributed Nb 3 Sn wire and preparation method thereof.

[0005] On the one hand, the present invention provides an optimized tin source distributed Nb 3 A method for preparing a Sn wire, the method comprising:

[0006] S1. Assemble the NbTi / Cu single core rod 100 and the Nb / Cu single core rod 200 in the oxygen-free copper sheath 300 to obtain a CuNb composite ingot containing the NbTi / Cu single core rod, and obtain a CuNb composite rod 600 containing a NbTi alloy after processing; in the CuNb composite ingot containing the NbTi / Cu single core rod, the Ti element accounts for 1.0~3.0at.% of the Nb element content.

[0007] S2. Obtain a Sn-X alloy rod through the processes of smelting, turning, machining, extrusion, drawing, forming and stretching, cutting to length, and straightening; load the Sn-X alloy rod into an oxygen-free copper tube, and obtain a Sn-X / Cu single core rod 500 through multiple cold drawing, forming, cutting to length, and straightening; in the Sn-X alloy rod, X is selected from Cu, Zn, and Ni, and the content of X is ≤5wt.%; the cross section of the Sn-X / Cu single core rod 500 is hexagonal or fan-shaped; the Sn-X / Cu single core rod 500 has the same specifications as the CuNb composite rod 600 containing NbTi alloy.

[0008] S3. Arrange and assemble the CuNb composite rod 600 containing NbTi alloy and the Sn-X / Cu single core rod 500 in the barrier layer material 400 in a hexagonal close-packed manner, so that, except for the Sn-X / Cu single core rod 500 at the edge position, each Sn-X / Cu single core rod 500 is surrounded by 6 CuNb composite rods 600 containing NbTi alloy adjacent to it, and then pass through the outer layer of copper 700 to obtain an optimized tin source distributed Nb 3 Sn composite ingot.

[0009] S4. Distribute the optimized tin source to Nb 3 Sn composite ingots are processed to obtain optimized tin source distributed Nb 3 Sn wire.

[0010] In S1 of the above preparation method, the preparation method of the NbTi / Cu single core rod 100 includes: placing a NbTi alloy ingot into an oxygen-free copper sheath to obtain a NbTi / Cu single core ingot, and performing degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain the NbTi / Cu single core rod 100; the Ti content of the NbTi alloy ingot is 30~60wt.%; the copper ratio of the prepared NbTi / Cu single core rod 100 is 0.20~0.50.

[0011] In S1 of the above preparation method, the preparation method of the Nb / Cu single core rod 200 includes: placing a Nb ingot into an oxygen-free copper sheath to obtain a Nb / Cu single core ingot, and performing degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain the Nb / Cu single core rod 200.

[0012] In S1 of the above preparation method, the NbTi / Cu single core rod 100 and the Nb / Cu single core rod 200 are assembled to satisfy the following conditions: the NbTi / Cu single core rod 100 is close to the edge and symmetrically distributed in the CuNb composite ingot containing the NbTi / Cu single core rod.

[0013] In S1 of the above preparation method, the processing of the CuNb composite ingot containing the NbTi / Cu single core rod includes: degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length, and straightening.

[0014] In S3 of the above preparation method, the barrier layer material 400 is a Nb or Ta alloy tube; and the outer layer copper 700 is an oxygen-free copper tube or an oxygen-free copper sheath.

[0015] In S3 of the above-mentioned preparation method, the edge position is filled with a Sn—X / Cu single core rod 500 having a fan-shaped cross section.

[0016] In S3 of the above preparation method, when the optimized tin source distributed Nb 3 The diameter of the Sn composite ingot is ≤75mm, which is loaded into an oxygen-free copper tube and subjected to multiple drawing, twisting, final stretching, chrome plating and heat treatment to obtain the optimized tin source distributed Nb 3 Sn wire; when the optimized tin source distributed Nb 3 The diameter of the Sn composite ingot is greater than 75 mm, and then it is placed in an oxygen-free copper sheath, covered with upper and lower covers, and then sequentially subjected to vacuum electron beam welding, hydrostatic extrusion, multi-pass drawing, twisting, final stretching, chrome plating and heat treatment to obtain the optimized tin source distributed Nb 3 Sn wire.

[0017] On the other hand, the present invention claims an optimized tin source distributed Nb prepared by the above method. 3 Sn wire.

[0018] Compared with the prior art, the present invention "an optimized tin source distributed Nb 3 Sn wire and its preparation method have at least the following beneficial effects:

[0019] The present invention distributes Nb in the tin source 3 In the preparation of Sn wire, the use of Ti-containing 6 Sn 5The SnTi alloy of the hard compound introduces the Ti element into the CuNb composite rod, and the percentage of Ti element to Nb element is between 1.0 and 3.0 at.%, which avoids the Ti 6 Sn 5 The wire breakage problem caused by hard compounds reduces the difficulty of wire processing.

[0020] The present invention adds Cu, Zn or Ni elements to Sn, which can increase the speed of Sn-Cu mutual diffusion during wire heat treatment and promote Nb 3 The formation of Sn is also conducive to the formation of Nb with uniform stoichiometric ratio. 3 Sn phase, thus effectively increasing the Nb 3 Critical current density of Sn wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the cross section of a CuNb composite ingot containing a NbTi / Cu single core rod.

[0022] Figure 2 For the optimized tin source distributed Nb 3 Schematic diagram of the cross section of a Sn composite ingot.

[0023] Figure 3 The optimized tin source distributed Nb 3 Changes in critical current density of Sn wire.

[0024] Explanation of the reference numerals: 100 is a NbTi / Cu single core rod; 200 is a Nb / Cu single core rod, 300 is an oxygen-free copper sheath; 400 is a barrier layer material, 500 is a Sn-X / Cu single core rod, 600 is a CuNb composite rod containing a NbTi alloy, and 700 is an outer layer of copper. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The embodiment of the present invention provides an optimized tin source distributed Nb 3 A method for preparing a Sn wire, the method comprising:

[0027] S1. Assemble the NbTi / Cu single core rod 100 and the Nb / Cu single core rod 200 in the oxygen-free copper sheath 300 to obtain a CuNb composite ingot containing the NbTi / Cu single core rod, and obtain a CuNb composite rod 600 containing a NbTi alloy after processing; in the CuNb composite ingot containing the NbTi / Cu single core rod, the Ti element accounts for 1.0~3.0at.% of the Nb element content.

[0028] S2. Obtain a Sn-X alloy rod through the processes of smelting, turning, machining, extrusion, drawing, forming and stretching, cutting to length, and straightening; load the Sn-X alloy rod into an oxygen-free copper tube, and obtain a Sn-X / Cu single core rod 500 through multiple cold drawing, forming, cutting to length, and straightening; in the Sn-X alloy rod, X is selected from Cu, Zn, and Ni, and the content of X is ≤5wt.%; the cross section of the Sn-X / Cu single core rod 500 is hexagonal or fan-shaped; the Sn-X / Cu single core rod 500 has the same specifications as the CuNb composite rod 600 containing NbTi alloy.

[0029] S3. Arrange and assemble the CuNb composite rod 600 containing NbTi alloy and the Sn-X / Cu single core rod 500 in the barrier layer material 400 in a hexagonal close-packed manner, so that, except for the Sn-X / Cu single core rod 500 at the edge position, each Sn-X / Cu single core rod 500 is surrounded by 6 CuNb composite rods 600 containing NbTi alloy adjacent to it, and then pass through the outer layer of copper 700 to obtain an optimized tin source distributed Nb 3 Sn composite ingot.

[0030] S4. Distribute the optimized tin source to Nb 3 Sn composite ingots are processed to obtain optimized tin source distributed Nb 3 Sn wire.

[0031] Illustratively, in S1 of the above-mentioned preparation method, the preparation method of the NbTi / Cu single core rod 100 includes: placing a NbTi alloy ingot into an oxygen-free copper sheath to obtain a NbTi / Cu single core ingot, and performing degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain the NbTi / Cu single core rod 100; the Ti content of the NbTi alloy ingot is 30~60wt.%; the copper ratio of the prepared NbTi / Cu single core rod 100 is 0.20~0.50.

[0032] Illustratively, in S1 of the above-mentioned preparation method, the preparation method of the Nb / Cu single core rod 200 includes: placing a Nb ingot into an oxygen-free copper sheath to obtain a Nb / Cu single core ingot, and performing degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain a Nb / Cu single core rod 200.

[0033] Illustratively, in S1 of the above preparation method, the NbTi / Cu single core rod 100 and the Nb / Cu single core rod 200 are assembled to satisfy: the NbTi / Cu single core rod 100 is close to the edge and symmetrically distributed in the CuNb composite ingot containing the NbTi / Cu single core rod.

[0034] Illustratively, in S1 of the above preparation method, the processing of the CuNb composite ingot containing the NbTi / Cu single core rod includes: degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length, and straightening.

[0035] Illustratively, in S3 of the above preparation method, the barrier layer material 400 is a Nb or Ta alloy tube; and the outer layer copper 700 is an oxygen-free copper tube or an oxygen-free copper sheath.

[0036] Exemplarily, in S3 of the above preparation method, the edge position is filled with a Sn—X / Cu single core rod 500 having a fan-shaped cross section.

[0037] For example, in S3 of the above preparation method, when the optimized tin source distributed Nb 3 The diameter of the Sn composite ingot is ≤75mm, which is loaded into an oxygen-free copper tube and subjected to multiple drawing, twisting, final stretching, chrome plating and heat treatment to obtain the optimized tin source distributed Nb 3 Sn wire; when the optimized tin source distributed Nb 3 The diameter of the Sn composite ingot is greater than 75 mm, and then it is placed in an oxygen-free copper sheath, covered with upper and lower covers, and then sequentially subjected to vacuum electron beam welding, hydrostatic extrusion, multi-pass drawing, twisting, final stretching, chrome plating and heat treatment to obtain the optimized tin source distributed Nb 3 Sn wire.

[0038] Example 1

[0039] This embodiment provides an optimized tin source distributed Nb 3 Preparation method of Sn wire.

[0040] Step 1: Put a Nb30Ti alloy ingot (Ti content is 30wt.%) into an oxygen-free copper sheath, cover the upper and lower covers to obtain a NbTi / Cu single-core ingot, and obtain a hexagonal NbTi / Cu single-core rod 100 through degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening; the copper ratio of the NbTi / Cu single-core rod 100 is 0.40, and the size is H5.00mm.

[0041] Step 2: Place the Nb ingot into an oxygen-free copper sheath, cover the upper and lower covers to obtain a Nb / Cu single-core ingot, and undergo degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain a Nb / Cu single-core rod 200 having the same specifications as the NbTi / Cu single-core rod 100 in step 1.

[0042] Step 3: After cleaning, the four NbTi / Cu single core rods 100 and the 195 Nb / Cu single core rods 200 are Figure 1 In the manner shown, the CuNb composite ingot containing a single core rod of NbTi / Cu is assembled in an oxygen-free copper sheath 300 to obtain a CuNb composite ingot containing a single core rod of NbTi / Cu. In the CuNb composite ingot containing a single core rod of NbTi / Cu, the Ti element accounts for 1.0 at.% of the Nb element content. The CuNb composite ingot containing a single core rod of NbTi / Cu is subjected to degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain a hexagonal CuNb composite rod 600 containing a NbTi alloy. The total number of cores of the CuNb composite rod 600 containing a NbTi alloy is 199, and the size is H2.00×1000mm.

[0043] Step 4: Obtain a Sn-Zn alloy rod through the processes of smelting, turning, machining, extrusion, drawing, forming and stretching, cutting to length, and straightening; the Sn-Zn alloy rod has a Zn content of 5wt.%. The Sn-Zn alloy rod is loaded into a cleaned oxygen-free copper tube, and subjected to multiple cold drawing, forming, cutting to length, and straightening to obtain a Sn-Zn / Cu single core rod 500; the size of the Sn-Zn / Cu single core rod 500 is the same as that of the CuNb composite rod 600 containing the NbTi alloy.

[0044] Step 5: After cleaning, 138 CuNb composite rods 600 containing NbTi alloy and 61 hexagonal Sn-Zn / Cu single core rods 500 are arranged and assembled in a Ta alloy tube of size Φ34 / Φ32×1000mm in a hexagonal close-packed manner, and the edge is filled with 12 cleaned fan-shaped Sn-Zn / Cu single core rods 500, so that except for the Sn-Zn / Cu single core rods 500 at the edge position, each Sn-Zn / Cu single core rod 500 is surrounded by 6 CuNb composite rods 600 containing NbTi alloy adjacent to it, as shown in FIG. Figure 2 After that, it passes through an oxygen-free copper tube with a size of Φ50 / Φ35×1000mm to obtain an optimized tin source distributed Nb 3 Sn composite ingot. The optimized tin source distributed Nb 3 The diameter of the Sn composite ingot is Φ50mm (i.e. the outer diameter of the oxygen-free copper tube).

[0045] Step 6: Distribute the optimized tin source to Nb 3 The Sn composite ingot is subjected to multiple drawing, twisting, final stretching, chrome plating and heat treatment to obtain an optimized tin source distributed Nb 3 Sn wire. The optimized tin source distributed Nb 3 The critical current density of Sn wire is: 2310A / mm 2 .

[0046] Example 2

[0047] This embodiment provides an optimized tin source distributed Nb 3 Preparation method of Sn wire.

[0048] Step 1: Put a Nb47Ti alloy ingot (Ti content is 47wt.%) into an oxygen-free copper sheath, cover the upper and lower covers to obtain a NbTi / Cu single-core ingot, and obtain a hexagonal NbTi / Cu single-core rod 100 through degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening; the copper ratio of the NbTi / Cu single-core rod 100 is 0.30, and the size is H5.00mm.

[0049] Step 2: Place the Nb ingot into an oxygen-free copper sheath, cover the upper and lower covers to obtain a Nb / Cu single-core ingot, and undergo degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain a Nb / Cu single-core rod 200 having the same specifications as the NbTi / Cu single-core rod 100 in step 1.

[0050] Step 3: After cleaning, 6 NbTi / Cu single core rods 100 and 307 Nb / Cu single core rods 200 are assembled in an oxygen-free copper sheath 300 to obtain a CuNb composite ingot containing NbTi / Cu single core rods. In the CuNb composite ingot containing NbTi / Cu single core rods, the Ti element accounts for 2.0 at.% of the Nb element content. The CuNb composite ingot containing NbTi / Cu single core rods is subjected to degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain a hexagonal CuNb composite rod 600 containing NbTi alloy. The total number of cores of the CuNb composite rod 600 containing NbTi alloy is 313, and the size is H6.00×2000mm.

[0051] Step 4: Obtain a Sn-Ni alloy rod through the processes of smelting, turning, machining, extrusion, drawing, forming and stretching, cutting to length, and straightening; the content of Ni in the Sn-Ni alloy rod is 3wt.%. The Sn-Ni alloy rod is loaded into a cleaned oxygen-free copper tube, and subjected to multiple cold drawing, forming, cutting to length, and straightening to obtain a Sn-Ni / Cu single core rod 500; the size of the Sn-Ni / Cu single core rod 500 is the same as that of the CuNb composite rod 600 containing the NbTi alloy.

[0052] Step 5: After cleaning, 84 CuNb composite rods 600 containing NbTi alloy and 37 hexagonal Sn-Ni / Cu single core rods 500 are arranged and assembled in a Nb alloy tube with a size of Φ76 / Φ74×600mm in a hexagonal close-packed manner, and the edge is filled with 6 cleaned fan-shaped Sn-Ni / Cu single core rods 500, so that except for the Sn-Ni / Cu single core rods 500 at the edge position, each Sn-Ni / Cu single core rod 500 is surrounded by 6 CuNb composite rods 600 containing NbTi alloy adjacent to it. Then pass through the oxygen-free copper sheath with a size of Φ110 / Φ77×660mm, cover the upper and lower covers, and obtain the optimized tin source distributed Nb 3 Sn composite ingot. The optimized tin source distributed Nb 3 The diameter of the Sn composite ingot is Φ110mm.

[0053] Step 6: Distribute the optimized tin source to Nb 3 The Sn composite ingot is subjected to vacuum electron beam welding, hydrostatic extrusion, multi-pass drawing, twisting, final stretching, chrome plating and heat treatment in sequence to obtain an optimized tin source distributed Nb 3 Sn wire. The optimized tin source distributed Nb 3 The critical current density of Sn wire is: 2470A / mm 2 .

[0054] Example 3

[0055] This embodiment provides an optimized tin source distributed Nb 3 Preparation method of Sn wire.

[0056] Step 1: Put a Nb60Ti alloy ingot (Ti content is 60wt.%) into an oxygen-free copper sheath, cover the upper and lower covers to obtain a NbTi / Cu single-core ingot, and obtain a hexagonal NbTi / Cu single-core rod 100 through degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening; the copper ratio of the NbTi / Cu single-core rod 100 is 0.50, and the size is H5.00mm.

[0057] Step 2: Place the Nb ingot into an oxygen-free copper sheath, cover the upper and lower covers to obtain a Nb / Cu single-core ingot, and undergo degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain a Nb / Cu single-core rod 200 having the same specifications as the NbTi / Cu single-core rod 100 in step 1.

[0058] Step 3: After cleaning, 18 NbTi / Cu single core rods 100 and 937 Nb / Cu single core rods 200 are assembled in an oxygen-free copper sheath 300 to obtain a CuNb composite ingot containing NbTi / Cu single core rods. In the CuNb composite ingot containing NbTi / Cu single core rods, the Ti element accounts for 3.0 at.% of the Nb element content. The CuNb composite ingot containing NbTi / Cu single core rods is subjected to degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain a hexagonal CuNb composite rod 600 containing NbTi alloy. The total number of cores of the CuNb composite rod 600 containing NbTi alloy is 955, and the size is H10.00×500mm.

[0059] Step 4: Obtain a Sn-Cu alloy rod through the processes of smelting, turning, machining, extrusion, drawing, forming and stretching, cutting to length, and straightening; the content of Cu in the Sn-Cu alloy rod is 2wt.%. The Sn-Cu alloy rod is loaded into a cleaned oxygen-free copper tube, and subjected to multiple cold drawing, forming, cutting to length, and straightening to obtain a Sn-Cu / Cu single core rod 500; the size of the Sn-Cu / Cu single core rod 500 is the same as that of the CuNb composite rod 600 containing the NbTi alloy.

[0060] Step 5: After cleaning, 84 CuNb composite rods 600 containing NbTi alloy and 37 hexagonal Sn-Cu / Cu single core rods 500 are arranged and assembled in a Ta alloy tube with a size of Φ125 / Φ123×500mm in a hexagonal close-packed manner, and the edge is filled with 6 cleaned fan-shaped Sn-Cu / Cu single core rods 500, so that except for the Sn-Cu / Cu single core rods 500 at the edge position, each Sn-Cu / Cu single core rod 500 is surrounded by 6 CuNb composite rods 600 containing NbTi alloy adjacent to it. Then pass through the oxygen-free copper sheath with a size of Φ180 / Φ126×560mm, cover the upper and lower covers, and obtain the optimized tin source distributed Nb 3 Sn composite ingot. The optimized tin source distributed Nb 3 The diameter of the Sn composite ingot is Φ180mm.

[0061] Step 6: Distribute the optimized tin source to Nb 3The Sn composite ingot is subjected to vacuum electron beam welding, hydrostatic extrusion, multi-pass drawing, twisting, final stretching, chrome plating and heat treatment in sequence to obtain an optimized tin source distributed Nb 3 Sn wire. The optimized tin source distributed Nb 3 The critical current density of Sn wire is: 2630A / mm 2 .

[0062] Example 4

[0063] This example describes the optimized tin source distributed Nb prepared in Examples 1 to 3. 3 Sn wire and ordinary Nb produced by prior art 3 Comparison of Sn wire properties.

[0064] Table 1. Nb provided by the present invention 3 Sn wire performance test results

[0065]

[0066] As shown in Table 1, compared with ordinary Nb 3 Sn wire, Nb prepared in Examples 1 to 3 3 The maximum length of Sn wire is significantly increased, indicating that the processing difficulty of the wire is reduced, avoiding the 6 Sn 5 The wire breakage problem during the stretching process. In addition, Nb 3 The critical current density of Sn wire is significantly improved, indicating that the wire has excellent current carrying capacity.

[0067] Example 5

[0068] This embodiment describes the optimized tin source distributed Nb under different Ti element contents. 3 Changes in critical current density of Sn wire.

[0069] Figure 3 The optimized tin source distributed Nb ingots containing NbTi / Cu single core rods with different Ti content (0.5~3.5at.%) were statistically analyzed. 3 Critical current density of Sn wire. Figure 3 It can be seen that the critical current density increases first and then decreases, and reaches a peak value when the Ti content is about 1.5 at.%; when the Ti content is less than 1.0 at.% or greater than 3.0 at.%, the critical current density decays significantly. It can be seen that when the Ti content is between 1.0 and 3.0 at.%, it is more conducive to improving the optimized tin source distributed Nb 3 Critical current density of Sn wire.

[0070] The embodiments described above are only some embodiments of the present invention, not all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. All other embodiments obtained without creative work and related deductions and substitutions made by ordinary technicians in the field under the conditions of the concept of the present invention belong to the scope of protection of the present invention.

Claims

1. A method for preparing an optimized tin source distributed Nb3Sn wire, characterized in that: include: S1. Assembling a NbTi / Cu single core rod (100) and a Nb / Cu single core rod (200) in an oxygen-free copper sheath (300) to obtain a CuNb composite ingot containing the NbTi / Cu single core rod, and processing to obtain a CuNb composite rod (600) containing a NbTi alloy; In the CuNb composite ingot containing the NbTi / Cu single core rod, the Ti element accounts for 1.0-3.0 at.% of the Nb element content; S2. Obtaining a Sn-X alloy rod by smelting, turning, machining, extrusion, drawing, forming and stretching, cutting to length, and straightening; loading the Sn-X alloy rod into an oxygen-free copper tube, and subjecting the tube to multiple cold drawing, forming, cutting to length, and straightening to obtain a Sn-X / Cu single core rod (500); In the Sn-X alloy rod, X is selected from Zn and Ni, and the content of X is ≤5wt.%; The cross section of the Sn-X / Cu single core rod (500) is hexagonal or fan-shaped; The Sn-X / Cu single core rod (500) and the CuNb composite rod (600) containing NbTi alloy have the same specifications; S3. Arranging and assembling the CuNb composite rod (600) containing NbTi alloy and the Sn-X / Cu single core rod (500) in a hexagonal close-packed manner in the barrier layer material (400), so that, except for the Sn-X / Cu single core rod (500) at the edge position, each Sn-X / Cu single core rod (500) is surrounded by 6 CuNb composite rods (600) containing NbTi alloy adjacent to it, and then passing through the outer layer of copper (700) to obtain an optimized tin source distributed Nb3Sn composite ingot; S4. Processing the optimized tin source distributed Nb3Sn composite ingot to obtain an optimized tin source distributed Nb3Sn wire.

2. The preparation method according to claim 1, characterized in that: In S1, the method for preparing the NbTi / Cu single core rod (100) comprises: placing a NbTi alloy ingot into an oxygen-free copper sheath to obtain a NbTi / Cu single core ingot, and performing degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length cutting, and straightening to obtain a NbTi / Cu single core rod (100); the Ti content of the NbTi alloy ingot is 30-60wt.%; and the copper ratio of the prepared NbTi / Cu single core rod (100) is 0.20-0.

50.

3. The preparation method according to claim 1, characterized in that: In S1, the method for preparing the Nb / Cu single core rod (200) comprises: placing a Nb ingot into an oxygen-free copper sheath to obtain a Nb / Cu single core ingot, and performing degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cutting to length, and straightening to obtain a Nb / Cu single core rod (200).

4. The preparation method according to claim 1, characterized in that: In S1, the NbTi / Cu single core rod (100) and the Nb / Cu single core rod (200) are assembled to satisfy the following conditions: the NbTi / Cu single core rod (100) is close to the edge and symmetrically distributed in the CuNb composite ingot containing the NbTi / Cu single core rod.

5. The preparation method according to claim 1, characterized in that: In S1, the processing of the CuNb composite ingot containing the NbTi / Cu single core rod includes: degassing, vacuum electron beam welding, hot isostatic pressing, extrusion, multi-pass drawing, hexagonal forming, cut-to-length, and straightening.

6. The preparation method according to claim 1, characterized in that: In S3, the barrier layer material (400) is a Nb or Ta alloy tube; and the outer layer copper (700) is an oxygen-free copper tube or an oxygen-free copper sheath.

7. The preparation method according to claim 1, characterized in that: In S3, the edge position is filled with a Sn-X / Cu single core rod (500) having a fan-shaped cross section.

8. The preparation method according to claim 1, characterized in that: In S3, when the diameter of the optimized tin source distributed Nb3Sn composite ingot is ≤75 mm, it is loaded into an oxygen-free copper tube, and subjected to multiple drawing, twisting, final stretching, chrome plating and heat treatment to obtain the optimized tin source distributed Nb3Sn wire; When the diameter of the optimized tin source distributed Nb3Sn composite ingot is greater than 75mm, it is placed in an oxygen-free copper sheath and covered with upper and lower covers, and then sequentially undergoes vacuum electron beam welding, hydrostatic extrusion, multi-pass drawing, twisting, final stretching, chrome plating and heat treatment to obtain the optimized tin source distributed Nb3Sn wire.

9. An optimized tin source distributed Nb3Sn wire, characterized in that: The method according to claim 1 is used to prepare the product.

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