Nb3Sn Conductor Bundle Layout to Minimize Reshaping Deformation
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Solution Overview
Problem
The production of Nb3Sn superconductor wires is challenging due to deformation issues during cross-sectional reshaping, leading to reduced superconducting current carrying capacity and risk of Sn contamination in the copper matrix, which can cause irreversible loss of superconductivity and mechanical weaknesses.
Innovation Solution
A finished conductor arrangement with a round outer tube and filling elements between sub-elements, forming a circular outer profile and a serrated inner profile, minimizes deformation and maintains uniform diffusion paths during reaction heat treatment, thereby enhancing the superconducting current carrying capacity and preventing Sn contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If sub-elements with hexagonal cross-section are bundled and subjected to cross-sectional reduction, then the desired geometry is achieved, but deformation occurs especially near the corners leading to reduced Nb3Sn formation and potential Sn contamination
Solution Approach 1:
The patent applies this principle by using a round outer tube instead of a hexagonal one, and by introducing filling elements with rounded profiles. This curvature eliminates the sharp corners that cause concentrated deformation during cross-sectional reduction, distributing the deformation more uniformly across the conductor structure and preventing the corner deformations that lead to Sn contamination and reduced Nb3Sn formation.
Solution Approach 2:
The filling elements serve as intermediaries between the sub-elements and the outer tube. These elements with their specific geometry (rounded outer profile, serrated inner profile) mediate the deformation process, providing support and guiding the deformation to occur uniformly without concentrating stress at corners, thereby preventing Sn leakage and ensuring proper Nb3Sn formation.
2Ease of operation
If cross-sectional reduction is applied to achieve desired geometry, then the conductor can be formed into coils, but Sn may spread uncontrollably into copper matrix and sheaths increasing electrical resistance
Solution Approach 1:
The rounded geometry of the outer tube and filling elements prevents Sn from concentrating and leaking at corner regions during deformation. The curved surfaces distribute the deformation uniformly, maintaining intact diffusion barriers and preventing Sn contamination of the copper matrix and sheaths, thus preserving low electrical resistance.
Solution Approach 2:
The filling elements are placed beforehand to cushion and control the deformation process during cross-sectional reduction. They prevent excessive deformation and Sn leakage by providing structural support and guiding the deformation to occur uniformly, thereby protecting against Sn contamination before it can occur.
3Shape
If deformation occurs during cross-sectional reduction, then geometry is achieved, but Nb material may be displaced radially outward reducing superconducting current-carrying capacity
Solution Approach 1:
The rounded outer tube and filling elements create a uniform deformation field during cross-sectional reduction, preventing the radial displacement of Nb material that occurs at hexagonal corners. This uniform deformation maintains the Nb filaments in their proper positions, ensuring complete Nb3Sn formation and preserving maximum current-carrying capacity.
Solution Approach 2:
The filling elements act as intermediaries that control and uniformize the deformation process. They prevent localized stress concentrations that would cause Nb filament displacement, ensuring that the deformation is distributed uniformly and Nb material remains properly positioned for optimal superconducting performance.
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
This approach allows for a high Nb3Sn content and current-carrying capacity while reducing Sn contamination in the conductor, ensuring a stable superconducting state and improved mechanical properties.
Implementation Method 1
deformation issues during cross-sectional reshaping
Implementation Method 2
maintains uniform diffusion paths during reaction heat treatment
Implementation Method 3
the tin in the PIT core reacts directly with the surrounding boron tube
Implementation Method 4
reaction heat treatment, transforming the finished conductor into the complete Nb3Sn superconducting wire
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
In summary, the invention proposes using a finished conductor arrangement (20; 50) for producing an Nb3Sn superconductor wire (33) in accordance with the RRP principle, in which arrangement hexagonal RRP subelements (1a; 60a) are combined to form a bundle which is approximately circular in cross section and are arranged, together with filler elements (18a -18c), in an external pipe (19; 52) which is round on the inside and on the outside. The filler elements (18a -18c) form, on the inside, a jagged profile (25) for making contact with the hexagonal subelements (1a; 60a) and, on the outside, a round profile (24) for direct or indirect contact in the external pipe. In this way, non-uniform deformations, in particular indentations, on the subelements (1a, 60a) are minimized during cross-section-reducing reshaping of the finished conductor arrangement (20, 50). For the manufacture of the RRP sub-elements (1; 60), the invention proposes manufacturing the RRP subelements before cross-section-reducing reshaping with an externally hexagonal and internally round shell structure (9) into which the remaining parts of the sub-element (1; 60) are inserted, in particular an annular arrangement of hexagonal Nb-containing rod elements (4) which are surrounded on the outside by an external matrix (7, 61) and on the inside by an internal matrix (3). In turn, non-uniform deformations, in particular azimuthal material redistributions, are minimized during subsequent cross-section-reducing reshaping of the subelements (1; 60). Overall, it is possible to obtain an Nb3Sn superconductor wire (33) with a high superconducting current-carrying capacity and minimized risk of Sn impurities in normally conducting regions, and therefore a good protective function in the event of quenching.