A kind of preparation method of high-strength mgb2 wire rod

Abstract

The invention discloses a high-strength MgB2 wire manufacturing method. The method includes: 1, manufacturing primary composite wires; 2 assembling secondary composite tubes; 3, drawing the secondary composite tubes for three times at 20%-25% pass processing rate, and then drawing at 10%-15% pass processing rate to obtain wires with required dimensions; 4, performing phase-formation heat treatment on the wires under the protection of argon atmosphere to obtain high-strength MgB2 wires with strength between 220MPa-280MPa. According to the method, CuAg alloy bars are used as reinforcement cores, manufactured multi-core super-conducting wires are transformed evenly, and inner parts are combined tightly, so that the manufactured multi-core super-conducting wires have good plasticity. According to the method, flow of powder in the drawing process is smooth. The method is particularly suitable for processing of MgB two-kilometer long wires and can meet requirements for practical application of super-conducting magnets, especially super-conducting nuclear magnetic resonance spectrometer and the like.

Description

technical field

[0001] The invention belongs to the technical field of superconducting material processing engineering, and in particular relates to a high-strength MgB 2 Method of wire preparation. Background technique

[0002] MgB 2 Its critical transition temperature is 39k, which has a higher superconducting transition temperature in metal compounds, and can work in the liquid hydrogen temperature region (10-20k), while traditional low-temperature superconductors cannot be applied in this temperature region, and expensive superconductors must be used Liquid helium, which increases the application cost. Through years of research, it has been found that MgB 2 Wires and strips can be prepared in different ways, such as in-situ PIT and ex-situ PIT technologies, both of which can produce kilometer-level long wires. In 2007, ASG, Columbus, and Paramed jointly developed the open MgB used in the temperature zone of the refrigerator. 2 - MRI superconducting magnets, which us...

Examples

Embodiment 1

[0034] Step 1. Mix amorphous boron powder, magnesium powder and amorphous carbon according to the atomic ratio of 1:1.95:0.05, and grind and mix them evenly under the protection of an argon atmosphere with a mass purity of 99.999% to obtain a precursor powder. The powder is put into the Nb / Cu composite tube, the two ends of the composite tube are blocked with cotton and one end of the composite tube is screwed tightly, and the composite tube is drawn at a processing rate of 10% to obtain a regular hexagon with an inscribed circle diameter of 3.56mm in cross section. Primary composite wire; the mass percentage of oxygen in the precursor powder is not more than 0.1%; in the Nb / Cu composite tube, Nb is used as an inner barrier layer, and Cu is used as an outer layer stabilizer;

[0035] Step two, such as figure 1 As shown, a first CuAg alloy rod 2 having the same size as the primary composite wire 1 described in step 1 and 6 primary composite wires 1 were placed in an oxygen-free...

Embodiment 2

[0039] This embodiment is the same as Embodiment 1, and the difference is that the assembly method of the secondary composite pipe is as follows: figure 2 As shown, 1 first CuAg alloy rod 2 having the same size as the primary composite wire 1, 6 primary composite wires 1 and 6 second CuAg alloy rods 4 (circular cross section with a diameter of 0.89mm) were placed Assemble in the oxygen-free copper tube 3 to obtain a secondary composite tube; the second CuAg alloy rod 4 is located in the gap between two adjacent primary composite wires 1 and the oxygen-free copper tube 3; the second CuAg The volume percentage of Ag in alloy rod 4 is 18%, and the balance is Cu; the prepared high-strength MgB 2 The strength of the wire is 280MPa.

Embodiment 3

[0041] Step 1. Mix amorphous boron powder, magnesium powder and amorphous carbon according to the atomic ratio of 1:1.95:0.05, and grind and mix them evenly under the protection of an argon atmosphere with a mass purity of 99.999% to obtain a precursor powder. The powder is put into the Nb / Cu composite tube, the two ends of the composite tube are blocked with cotton and one end of the composite tube is screwed tightly, and the one end of the composite tube is pulled with a processing rate of 15% to obtain a circular primary composite wire with a cross-section of 3.56 mm in diameter; The mass percentage of oxygen in the precursor powder is not more than 0.1%; in the Nb / Cu composite tube, Nb is used as an inner barrier layer, and Cu is used as an outer layer stabilizer;

[0042] Step two, such as image 3 As shown, a first CuAg alloy rod 2 having the same size as the primary composite wire 1 described in step 1 and 6 primary composite wires 1 were placed in an oxygen-free copper...

technical field

[0001] The invention belongs to the technical field of superconducting material processing engineering, and in particular relates to a high-strength MgB 2 Method of wire preparation. Background technique

[0002] MgB 2 Its critical transition temperature is 39k, which has a higher superconducting transition temperature in metal compounds, and can work in the liquid hydrogen temperature region (10-20k), while traditional low-temperature superconductors cannot be applied in this temperature region, and expensive superconductors must be used Liquid helium, which increases the application cost. Through years of research, it has been found that MgB 2 Wires and strips can be prepared in different ways, such as in-situ PIT and ex-situ PIT technologies, both of which can produce kilometer-level long wires. In 2007, ASG, Columbus, and Paramed jointly developed the open MgB used in the temperature zone of the refrigerator. 2 - MRI superconducting magnets, which us...

Examples

Embodiment 1

[0034] Step 1. Mix amorphous boron powder, magnesium powder and amorphous carbon according to the atomic ratio of 1:1.95:0.05, and grind and mix them evenly under the protection of an argon atmosphere with a mass purity of 99.999% to obtain a precursor powder. The powder is put into the Nb / Cu composite tube, the two ends of the composite tube are blocked with cotton and one end of the composite tube is screwed tightly, and the composite tube is drawn at a processing rate of 10% to obtain a regular hexagon with an inscribed circle diameter of 3.56mm in cross section. Primary composite wire; the mass percentage of oxygen in the precursor powder is not more than 0.1%; in the Nb / Cu composite tube, Nb is used as an inner barrier layer, and Cu is used as an outer layer stabilizer;

[0035] Step two, such as figure 1 As shown, a first CuAg alloy rod 2 having the same size as the primary composite wire 1 described in step 1 and 6 primary composite wires 1 were placed in an oxygen-free...

Embodiment 2

[0039] This embodiment is the same as Embodiment 1, and the difference is that the assembly method of the secondary composite pipe is as follows: figure 2 As shown, 1 first CuAg alloy rod 2 having the same size as the primary composite wire 1, 6 primary composite wires 1 and 6 second CuAg alloy rods 4 (circular cross section with a diameter of 0.89mm) were placed Assemble in the oxygen-free copper tube 3 to obtain a secondary composite tube; the second CuAg alloy rod 4 is located in the gap between two adjacent primary composite wires 1 and the oxygen-free copper tube 3; the second CuAg The volume percentage of Ag in alloy rod 4 is 18%, and the balance is Cu; the prepared high-strength MgB 2 The strength of the wire is 280MPa.

Embodiment 3

[0041] Step 1. Mix amorphous boron powder, magnesium powder and amorphous carbon according to the atomic ratio of 1:1.95:0.05, and grind and mix them evenly under the protection of an argon atmosphere with a mass purity of 99.999% to obtain a precursor powder. The powder is put into the Nb / Cu composite tube, the two ends of the composite tube are blocked with cotton and one end of the composite tube is screwed tightly, and the one end of the composite tube is pulled with a processing rate of 15% to obtain a circular primary composite wire with a cross-section of 3.56 mm in diameter; The mass percentage of oxygen in the precursor powder is not more than 0.1%; in the Nb / Cu composite tube, Nb is used as an inner barrier layer, and Cu is used as an outer layer stabilizer;

[0042] Step two, such as image 3 As shown, a first CuAg alloy rod 2 having the same size as the primary composite wire 1 described in step 1 and 6 primary composite wires 1 were placed in an oxygen-free copper...

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