Effect of Third-Element Additions on the Upper Critical Field of Bronze-Processed&amp;lt;tex&amp;gt;$rm Nb_3rm Sn$&amp;lt;/tex&amp;gt;

Kurahashi, H.; Itoh, K.; Matsumoto, Shinji; Toko, Kiyoshi; Wada, Hitoshi; Murakami, Y.; Yasunaka, Hiroyuki; Hayashi, Shigenari; Otani, Yasumi

doi:10.1109/tasc.2005.848914

Cited by 9 publications

(6 citation statements)

References 19 publications

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“…Possibilities for improving the superconducting properties of the Nb-Sn system by the use of third-and fourth-element additions have been extensively investigated (see [31,46,47,[67][68][69][70][71][72][73][74][75][76][77][78]) and reviewed [4,45]. Of a wide range of possible ternary additions, Ta and Ti are most widely applied in wires.…”

Section: Titanium and Tantalum Additionsmentioning

confidence: 99%

A review of the properties of Nb₃Sn and their variation with A15 composition, morphology and strain state

Godeke¹

2006

Supercond. Sci. Technol.

224

213

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Significant efforts can be found throughout the literature to optimize the current carrying capacity of Nb3Sn superconducting wires. The achievable transport current density in wires depends on the A15 composition, morphology and strain state. The A15 sections in wires contain, due to compositional inhomogeneities resulting from solid state diffusion A15 formation reactions, a distribution of superconducting properties. The A15 grain size can be different from wire to wire and is also not necessarily homogeneous across the A15 regions. Strain is always present in composite wires, and the strain state changes as a result of thermal contraction differences and Lorentz forces in magnet systems. To optimize the transport properties it is thus required to identify how composition, grain size and strain state influence the superconducting properties. This is not accurately possible in inhomogeneous and spatially complex systems such as wires. This article therefore gives an overview of the available literature on simplified, well defined (quasi-)homogeneous laboratory samples. After more than 50 years of research on superconductivity in Nb3Sn, a significant amount of results are available, but these are scattered over a multitude of publications. Two reviews exist on the basic properties of A15 materials in general, but no specific review for Nb3Sn is available. This article is intended to provide such an overview. It starts with a basic description of the Niobium-Tin intermetallic. After this it maps the influence of Sn content on the the electron-phonon interaction strength and on the field-temperature phase boundary. The literature on the influence of Cu, Ti and Ta additions will then be briefly summarized. This is followed by a review on the effects of grain size and strain. The article is concluded with a summary of the main results.

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Section: Titanium and Tantalum Additionsmentioning

confidence: 99%

A review of the properties of Nb₃Sn and their variation with A15 composition, morphology and strain state

Godeke¹

2006

Supercond. Sci. Technol.

224

213

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“…The O+Sn sample appears it will be superior for times greater than 10 hours at 850˚C. Measurements of the 1000˚C samples showed a marked drop in apparent H* with the SnO 2 sample having an H* of 10 T. The other samples appeared to be resistive above 6 T. Kuranhashi, et al reported a marked drop in T c and B c2 in bronze matrix conductors between a peak of 850˚C and 940˚C with B c2 at 940˚C of 20T [48]. Also the ternary appears to show 2 at% of Cu in solution though there is some disagreement in phase diagrams.…”

Section: Experiments To Demonstrate the Best Extrusion And Drawing Comentioning

confidence: 97%

A Method to Increase Current Density in a Mono Element Internal Tin Processed Superconductor Utilizing Zr Oxide to Refine Grain Size

Zeitlin¹,

Gregory²

2008

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The effect of Oxygen on (Nb1Zr) 3 Sn multifilament conductors manufactured by the Mono Element Internal Tin (MEIT) process was explored to improve the current density by refining the grain size. This followed work first done by General Electric on the Nb 3 Sn tape process. Techniques to fabricate the more difficult Nb1Zr composites are described and allowed fabrication of long lengths of .254 mm diameter wire from an 88.9 mm diameter billet. Oxygen was incorporated through the use of SnO 2 mixed with tin powder and incorporated into the core. These were compared to samples with Ti+Sn and Cu+Sn cores. Heat treatments covered the range of 700˚C to 1000˚C. Current density vs. H, grain size, and reaction percentages are provided for the materials tested. The Oxygen gave superior results in the temperature range of 815-1000˚C. It also stabilized the filament geometry of the array in comparison to the other additions at the higher temperatures. At 815˚C a peak in layer J c yielded values of 2537 A/mm 2 at 12 T and 1353 A/mm 2 at 15T, 8-22% and 30-73% greater respectively than 700˚C values. Results with Oxygen at high temperature show the possibility of high speed continuous reaction of the composite versus the current batch or react in place methods. In general the Ti additions gave superior results at the lower reaction temperature. Future work is suggested to determine if the 815˚C reaction temperature can lead to higher current density in high tin (Nb1Zr+O x) 3 Sn conductors. A second technique incorporated oxygen directly into the Nb1Zr rods through heat treatment with Nb 2 O 5 at 1100˚C for 100 hours in vacuum prior to extrusion. The majority of the filaments reduced properly in the composite but some local variations in hardness led to breakage at smaller diameters.

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“…It is also known that some third element additions can substantially influence some specific superconducting properties of Nb 3 Sn conductors. Although there are still concerns, in recent years, about dopping in bronze-processed strands [12], the internal-Sn strands are more popular in which the alloyed element is preferable to Ti [13] or Ta [14]. More recently, alloying Zr in Nb 3 Sn strands has also attracted rather big attention [15].…”

Section: Introductionmentioning

confidence: 99%

Representation of A15 composition and T C in internal-Sn Nb3Sn superconducting strands

Zhang¹,

Zhou²,

Sulpice³

et al. 2010

Sci. China Technol. Sci.

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Four sets of mono-element (ME) and two kinds of multifilament (MF) internal-Sn Nb 3 Sn superconducting strands were designed and fabricated through RRP method in which different compoment ratios, various composite configurations and some third element alloying were arranged. All the strand samples underwent a 210°C/50 h + 340°C/25 h thermal duration for Cu-Sn alloying. After that A15 phase formation heat treatment (HT) was applied for which the ME samples were chosen at three reaction temperatures of 675°C, 700°C and 725°C for 100 h and 200 h while the MF samples at four temperatures of 650°C, 675°C, 700°C and 725°C for 128 h and 200 h. The heat-treated samples were examined for A15 phase composition distribution by X-ray EDS. SQUID magnetization measurement was used to determine critical temperature T C . The obtained results demonstrate that for fully-reacted internal-Sn Nb 3 Sn superconductors the A15 phase composition and the intrinsic property T C are determined by the diffusion and solid state reaction mechanism and are independent of the factors including HT temperature, strand composite component and configuration arrangement, and the third element addition within the experimental range.internal-Sn Nb 3 Sn strands, A15 phase composition, phase formation heat treatment, composite configuration and design, third element alloying Citation:Zhang C W, Zhou L, Sulpice A, et al.

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Effect of Third-Element Additions on the Upper Critical Field of Bronze-Processed<tex>$rm Nb_3rm Sn$</tex>

Cited by 9 publications

References 19 publications

A review of the properties of Nb₃Sn and their variation with A15 composition, morphology and strain state

A review of the properties of Nb₃Sn and their variation with A15 composition, morphology and strain state

A Method to Increase Current Density in a Mono Element Internal Tin Processed Superconductor Utilizing Zr Oxide to Refine Grain Size

Representation of A15 composition and T C in internal-Sn Nb3Sn superconducting strands

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Effect of Third-Element Additions on the Upper Critical Field of Bronze-Processed&lt;tex&gt;$rm Nb_3rm Sn$&lt;/tex&gt;

Cited by 9 publications

References 19 publications

A review of the properties of Nb3Sn and their variation with A15 composition, morphology and strain state

A review of the properties of Nb3Sn and their variation with A15 composition, morphology and strain state

A Method to Increase Current Density in a Mono Element Internal Tin Processed Superconductor Utilizing Zr Oxide to Refine Grain Size

Representation of A15 composition and T C in internal-Sn Nb3Sn superconducting strands

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Product

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Effect of Third-Element Additions on the Upper Critical Field of Bronze-Processed<tex>$rm Nb_3rm Sn$</tex>

A review of the properties of Nb₃Sn and their variation with A15 composition, morphology and strain state

A review of the properties of Nb₃Sn and their variation with A15 composition, morphology and strain state