Effect of Diffusion Annealing and Design of Internal Tin Wires on the Structure and Morphology of Superconducting Nb<sub>3</sub>Sn Layers

Deryagina, I. L.; Попова, Е. Н.; Патраков, Е. И.; Valova-Zaharevskaya, E.G.

doi:10.1109/tasc.2016.2517189

Cited by 13 publications

(3 citation statements)

References 38 publications

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“…For the MF1980-12Zn reference wires heat treated at 670 °C, 700 °C and 730 °C, the calculated F p,max is about 3∼4 GN m −3 smaller than the MF1980-12Zn-0.2Mg specimens, which might be due to the larger grain size and larger area fraction of columnar grains in the Nb 3 Sn filaments. The columnar structure grains have higher fractions of low-angle grain boundaries, which are less efficient pins than the high-angle grain boundaries mainly formed in the equiaxial grains [24][25][26].…”

Section: Discussionmentioning

confidence: 99%

The effects of Mg doping on the microstructure and transport properties of internal tin-processed brass matrix Nb₃Sn superconductors

Banno

Zhao

et al. 2019

Supercond. Sci. Technol.

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The addition of Zn into Cu matrix has been proved to enhance the Sn activity and accelerate the formation of a Nb3Sn layer in internal tin-processed Nb3Sn wires. However, in our samples, Ti is doped in Sn cores, and during the reaction, Ti was observed to accumulate between the inner and outer sub-elements of the 1980-Nb-core multi-filamentary brass matrix wires. With the addition of Mg into the brass matrix, Ti accumulation between the sub-elements was significantly suppressed, which promoted Ti incorporation into the Nb3Sn layers. Meanwhile, the formed Nb3Sn layers exhibited smaller grain sizes. Compared to the brass (Cu-12wt%Zn) matrix wires, an improvement of critical current density (Jc) was found in the Cu-12Zn-0.2Mg matrix wires due to the incorporation of Ti into the Nb3Sn layer and the refinement of the Nb3Sn grain size. The irreversibility field (Birr) and maximum bulk pinning forces (Fp,max) were calculated from the Kramer plot by analyzing the Jc(B) curves. A small amount of Mg (0.2 wt%) doping into the Cu-12Zn matrix wires can increase the Birr value by about 0.5 T and the Fp,max value by about 3 ∼ 4 GN m−3 after the wires were heat treated between 670 °C and 730 °C. The non-Cu Jc of the Cu-12Zn-0.2Mg matrix wires reaches the maximum value of 1533 A mm−2 @12 T after heat treatment at 685 °C and decreases at higher temperatures.

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Section: Discussionmentioning

confidence: 99%

The effects of Mg doping on the microstructure and transport properties of internal tin-processed brass matrix Nb₃Sn superconductors

Banno

Zhao

et al. 2019

Supercond. Sci. Technol.

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“…The grain size of conventional Nb 3 Sn is ∼200 nm. Recent investigations on Nb 3 Sn pinning characteristics suggest that the grain boundary of the coarse grain A15 phase does not have a significant impact on the pinning force and maximizing of the fine equiaxed grain area is essential for further J c improvement [15,[20][21][22]]. An internal oxidation technique using Nb-Zr alloys is now actively discussed as a technique to refine the grain morphology of the Nb 3 Sn layer [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

“…Cu-Zn/Sn diffusion reactions and void formation behaviors have also not yet been investigated in detail. In addition, there are only few studies on the influence of the Ti doping mode in the internal tin Nb 3 Sn strand so far [22,49]. It should be noted that there are exactly three paths for Ti doping in internal tin processes, i.e.…”

Section: Introductionmentioning

confidence: 99%

Effect of Zn addition and Ti doping position on the diffusion reaction of internal tin Nb₃Sn conductors

Banno¹,

Morita²,

Yu³

et al. 2019

Supercond. Sci. Technol.

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Addition of Zn to a Cu matrix during Cu–Zn/Sn interdiffusion reactions at 400 °C leads to the formation of a solid ternary Cu–Zn–Sn phase, β-CuZn, at the outermost reaction layer next to the porous ε phase. The use of a brass matrix considerably suppresses void formation and promotes homogeneous outward Sn diffusion in pre-annealing, prior to Nb3Sn formation. There are exactly three paths for Ti doping in the internal tin process, i.e. doping to Sn cores, Nb filaments, and Cu matrix. Ti doping to Sn cores causes a Ti-rich layer formation at the boundary of the Nb filament pack; however, no Ti-rich layers are formed as a result of small Ti doping to the matrix and to Nb filaments. The absence of Ti-rich layers is believed to contribute to a smooth Sn diffusion and suppression of void growth. Atom probe tomography measurements reveal that Ti doping to Sn cores leads to a more inhomogeneous Ti distribution near the grain boundary and a larger variation of the grain boundary thickness than doping to Nb filaments, which may contribute to a better Sn grain boundary diffusion. It is concluded that Ti doping to the matrix, instead of doping to Sn cores, might be more effective in maintaining better growth kinetics of Nb3Sn.

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Effect of Nb3Sn layer structure and morphology on critical current density of multifilamentary superconductors

Deryagina

Попова

Патраков

et al. 2017

Journal of Magnetism and Magnetic Materials

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Effect of Diffusion Annealing and Design of Internal Tin Wires on the Structure and Morphology of Superconducting Nb₃Sn Layers

Cited by 13 publications

References 38 publications

The effects of Mg doping on the microstructure and transport properties of internal tin-processed brass matrix Nb₃Sn superconductors

The effects of Mg doping on the microstructure and transport properties of internal tin-processed brass matrix Nb₃Sn superconductors

Effect of Zn addition and Ti doping position on the diffusion reaction of internal tin Nb₃Sn conductors

Effect of Nb3Sn layer structure and morphology on critical current density of multifilamentary superconductors

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Effect of Diffusion Annealing and Design of Internal Tin Wires on the Structure and Morphology of Superconducting Nb3Sn Layers

Cited by 13 publications

References 38 publications

The effects of Mg doping on the microstructure and transport properties of internal tin-processed brass matrix Nb3Sn superconductors

The effects of Mg doping on the microstructure and transport properties of internal tin-processed brass matrix Nb3Sn superconductors

Effect of Zn addition and Ti doping position on the diffusion reaction of internal tin Nb3Sn conductors

Effect of Nb3Sn layer structure and morphology on critical current density of multifilamentary superconductors

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Effect of Diffusion Annealing and Design of Internal Tin Wires on the Structure and Morphology of Superconducting Nb₃Sn Layers

The effects of Mg doping on the microstructure and transport properties of internal tin-processed brass matrix Nb₃Sn superconductors

The effects of Mg doping on the microstructure and transport properties of internal tin-processed brass matrix Nb₃Sn superconductors

Effect of Zn addition and Ti doping position on the diffusion reaction of internal tin Nb₃Sn conductors