Enhanced current capacity of jelly-roll processed and transformed Nb/sub 3/Al multifilamentary conductors

Takeuchi, T.; Tagawa, K.; Toko, Kiyoshi; Itoh, K.; Kosuge, M.; Yuyama, M.; Wada, Hitoshi; Iijima, Y.; Inoue, Kiyoshi; Nakagawa, Kazuma; Iwaki, G.; Moriai, H.

doi:10.1109/77.785039

Cited by 39 publications

(24 citation statements)

References 12 publications

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“…This process produces highly stoichiometric Nb 3 Al with fine grain structures and, hence, large J c over the whole range of magnetic fields, comprising high fields, with B > 20 T. The excellent strain tolerance of Nb 3 Al conductors with respect to Nb 3 Sn and the improved high-field performance are very promising properties of Nb 3 Al wires [25]. In the rapid-heating, quenching and transformation (RHQT) method, an excellent Nb 3 Al conductor can be obtained with a multifilamentary structure over several hundreds of metres in length [25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Nb₃Al conductors for high-field applications

Takeuchi¹

2000

Supercond. Sci. Technol.

165

111

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Nb3Al has been considered as an alternative to Nb3Sn for high-field and large-scale applications, since an extremely high critical current density and excellent strain tolerance were demonstrated in Nb3Al by laboratory tests. Thus, there have been a great number of efforts in the exploration of new fabrication processes for Nb3Al. The processes explored can be classified into three groups: low-temperature processes (jelly-roll, powder metallurgy, clad chip extrusion, rod-in-tube), high-temperature processes (laser- or electron-beam irradiation), and transformation processes. This review describes Nb3Al conductors for each processing group, focusing on current topics relating to the rapid-heating, quenching and transformation method in which an excellent Nb3Al conductor can be obtained with a multifilamentary structure over several hundred metres in length.

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Section: Introductionmentioning

confidence: 99%

Nb₃Al conductors for high-field applications

Takeuchi¹

2000

Supercond. Sci. Technol.

165

111

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“…With the increase of the Sn doping amount, the T c increase first from 16.5 to 17.1 K and then decreases to 16.7 K, where the Nb 3 Al 1− x Sn x ( x = 0.04) sample shows the highest T c of 17.1 K. The highest T c of our Nb 3 Al 1− x Sn x wires are close to the reported 17.5 K for the RHQT JR binary Nb 3 Al wires fabricated by NIMS. [ 24,25 ] Figure 8c shows that the Δ T c of all the samples is in the range of 0.4–0.9 K, where the Nb 3 Al 1− x Sn x ( x = 0.04) sample exhibits the smallest Δ T c value of 0.4 K. It is notable that the JR Nb 3 Al wire and PIT Nb 3 Al 1− x Sn x wire show comparable T c and Δ T c results, indicating almost the same composition distribution of the A15 phase, even if the Nb layer thickness (approximately the Al diffusion distance) of our PIT wire is ≈50 times thicker than that of the NIMS JR wire. A longer Al diffusion distance inevitably results in wider composition distribution of the formed A15 phase; thus, Sn addition seems to suppress the content distribution in the A15 phase.…”

Section: Resultsmentioning

confidence: 94%

Microstructure and Superconducting Properties of Rapid Heating, Quenching, and Transformation (RHQT) Powder‐in‐Tube Nb₃Al Wires Doped with Sn Element

Ran

Chen

et al. 2021

Physica Status Solidi (a)

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Properties of rapid heating, quenching, and transformation (RHQT)‐treated powder‐in‐tube (PIT) Nb3Al1−xSnx wires are studied herein. After the RHQ process, the body‐centered cubic (bcc) phase is formed in the Sn‐doped Nb3Al wires. The transformed superconducting A15 phase shows a uniform microstructure and homogenous component distribution feature. With the increase of the Sn doping level, the critical transition temperature (Tc), critical current density (Jc), and irreversibility field (Birr) of the superconducting wires increase first and then reduce, achieving the highest Tc value of 17.6 K and the smallest ΔTc of 0.6 K in the 4% Sn doped Nb3Al wire. The 4% Sn addition helps to improve the layer Jc of the sample to 2.1 × 105 A cm−2 at 8 K and 5 T, which is about 2.5 times that of the pure Nb3Al sample. Furthermore, the Nb3Al1−xSnx (x = 0.04) wire gives the highest Birr value of 17.22, 13.23, and 9.11 T at 8, 10, and 12 K, respectively. The addition of Sn helps to achieve stoichiometric Nb3Al A15 phase and formation of precipitations with the size of 10 nm, which might act as the flux‐pinning center.

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“…After the RHQ step, the samples are usually stabilized with a Cu-cladding technique, using ductility of the Nb/Nb(Al) ss . It has been found that such deformations rather improve the J c property than degrade in the RHQT Nb 3 Al [15][16][17][18]. The dependence of J c on the deformation for the TRUQ Nb 3 Al conductors is described in this paper.…”

Section: Fabrication Steps For Truq Nb 3 Al Superconductorsmentioning

confidence: 84%

Optimization of the TRUQ (Transformation-heat-based up-quenching) method for Nb₃Al superconductors

Banno

Takeuchi

Fukuzaki

et al. 2002

Supercond. Sci. Technol.

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The newly developed transformation-heat-based up-quenching (TRUQ) process causes an improvement of the stoichiometry of the A15 Nb 3 Al phase and an enhancement of the high-field J c performance in Nb 3 Al superconductors. J c properties have been optimized in the fabrication steps for TRUQ Nb 3 Al superconductors. The TRUQ process in the vicinity of 1000 • C gives the best high-field and low-field J c 's as well as T c and B c2 . J c 's are not so sensitive to the holding time of the TRUQ process, which makes rapid cooling unnecessary. The TRUQ process can be well applied to conventional Cu-clad stabilized conductors. The J c of 550 A mm −2 for the superconducting area is obtained at 23 T and 2 K; this is the highest measured value for A15-type superconductors. Thus, TRUQ Nb 3 Al conductors are very promising for high-field applications, e.g. GHz-class NMR magnets. Temperature profiles of the samples have been measured during the TRUQ process and it has been shown that TRUQ can be induced, even if the heating rate is less than 20 • C s −1 . The TRUQ process may be suitable for practical coil fabrications.

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Enhanced current capacity of jelly-roll processed and transformed Nb/sub 3/Al multifilamentary conductors

Cited by 39 publications

References 12 publications

Nb₃Al conductors for high-field applications

Nb₃Al conductors for high-field applications

Microstructure and Superconducting Properties of Rapid Heating, Quenching, and Transformation (RHQT) Powder‐in‐Tube Nb₃Al Wires Doped with Sn Element

Optimization of the TRUQ (Transformation-heat-based up-quenching) method for Nb₃Al superconductors

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Enhanced current capacity of jelly-roll processed and transformed Nb/sub 3/Al multifilamentary conductors

Cited by 39 publications

References 12 publications

Nb3Al conductors for high-field applications

Nb3Al conductors for high-field applications

Microstructure and Superconducting Properties of Rapid Heating, Quenching, and Transformation (RHQT) Powder‐in‐Tube Nb3Al Wires Doped with Sn Element

Optimization of the TRUQ (Transformation-heat-based up-quenching) method for Nb3Al superconductors

Contact Info

Product

Resources

About

Nb₃Al conductors for high-field applications

Nb₃Al conductors for high-field applications

Microstructure and Superconducting Properties of Rapid Heating, Quenching, and Transformation (RHQT) Powder‐in‐Tube Nb₃Al Wires Doped with Sn Element

Optimization of the TRUQ (Transformation-heat-based up-quenching) method for Nb₃Al superconductors