Nb-Al Precursor Wire Structure for Flexible Small-Diameter Coils
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Solution Overview
Problem
Niobium-aluminum (Nb3Al) superconducting wires face challenges due to their hard and brittle mechanical properties, making them difficult to coil and bend without breaking, and existing production methods struggle to achieve wire diameters smaller than 0.2 mm, limiting their practical application and flexibility.
Innovation Solution
A niobium-aluminum precursor wire with a copper stabilizer ratio of 0.5 to 2.0 is developed, featuring a core and covering body with specific volume percentages of copper stabilizer, allowing for a balanced mechanical structure and enabling wire diameters as small as 0.05 mm and lengths of 1,000 m, achieved through a lamination structure with a copper tube and diffusion barrier layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If niobium-aluminum superconducting wire is made with higher copper stabilizer content to improve flexibility and bendability, then ease of operation improves, but the volume ratio of copper stabilizer increases which may affect superconducting performance
Solution Approach 1:
The patent applies local quality by creating a non-uniform copper stabilizer distribution throughout the wire structure. The core region contains a first copper stabilizer volume with a specific copper ratio, while the outer region contains a second copper stabilizer volume with a different copper ratio. This spatial variation in copper stabilizer concentration allows the wire to achieve adequate flexibility for handling while maintaining optimal superconducting properties in the critical Nb3Al formation region.
Solution Approach 2:
The patent employs composite materials by combining copper stabilizer with non-copper stabilizer materials in different regions of the wire. The core contains copper stabilizer at a first ratio, while the outer region contains copper stabilizer mixed with non-copper stabilizer at a second ratio. This composite structure provides both the flexibility needed for wire drawing and bending operations and the superconducting performance required for high-field applications.
2Adaptability or versatility
If wire diameter is reduced to achieve smaller dimensions for practical applications, then adaptability improves, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent applies segmentation by dividing the wire structure into distinct core and outer regions, each with specific copper stabilizer and non-copper stabilizer ratios. This segmented approach allows independent optimization of each region's properties, enabling precise control over the overall wire dimensions and composition even at small diameters of 0.05 mm or less.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the copper stabilizer to non-copper stabilizer ratios in different regions, as well as controlling the absolute volumes of stabilizer materials. By adjusting these parameters within specific ranges (first ratio in core, second ratio in outer region), the invention achieves both small wire diameters and high manufacturing precision for dimensional control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a flexible and stable niobium-aluminum wire with improved bendability and coiling capabilities, suitable for high-performance superconducting applications, maintaining superconductivity even at small diameters and long lengths, similar to niobium-titanium alloy wires.
Implementation Method 1
Niobium and aluminum have extremely slow diffusion velocities at temperatures of 1,000° C. or less, and thus it is difficult to synthesize an A15-type niobium-aluminum (Nb3Al) superconducting phase.
Implementation Method 2
a niobium-aluminum superconducting wire having a superconducting phase, which is imparted by heat-treating the above-described niobium-aluminum precursor wire
Data Source
AI summary
The purpose of the present invention is to provide a niobium-aluminum precursor wire having properties such as expression of flexibility and ensuring a large single-wire length, as well as a twisted wire, a superconducting wire, and a superconducting twisted wire formed of the niobium-aluminum precursor wire. The present invention provides a niobium-aluminum precursor wire and a twisted wire using the same, the niobium-aluminum precursor wire including: a rod-like winding core (5) formed of a stabilized copper, or a stabilized copper and an unstabilized copper; a laminated body (3) that is wound around the winding core (5) and that is formed of an aluminum foil and a niobium foil laminated one on the other; and a covering body (1) that covers the circumference of the laminated body and that is formed of a stabilized copper, or a stabilized copper and an unstabilized copper. The volume ratio of the stabilized copper with respect to the unstabilized copper contained in the precursor wire is 0.5-2.0, and the volume ratios of the stabilized copper contained in the winding core (5) and the covering body (1) are within prescribed ranges. According to the present invention, a superconducting wire and a superconducting twisted wire are provided by thermally treating the precursor wire and the twisted wire.