The Nb3Sn layers formation at diffusion annealing of Ti-doped multifilamentary Nb/Cu–Sn composites

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

doi:10.1016/j.cryogenics.2014.07.007

Cited by 37 publications

(14 citation statements)

References 27 publications

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“…The reason for the smaller grain size in 14Zn-MT0.2 is considered to be the smaller amount of Ti addition. As previously reported, the grain size tends to decrease at decreasing Ti addition in the Nb 3 Sn layer [41,47].…”

Section: Comparison Of Grain Sizesupporting

confidence: 82%

“…For Ti doping, two paths are possible in the bronze process, namely doping to the Nb cores and the bronze matrix. The influence of the Ti doping position on the microstructure and J c characteristics of the bronze-processed wires has been actively investigated by a Russian group [47][48][49]. They showed that Ti doping to the matrix tends to increase the equiaxed grain region of the Nb 3 Sn layer and refine the grain morphology compared with Ti doping to Nb cores.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Comparison Of Grain Sizesupporting

confidence: 82%

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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“…This temperature range is of special interest also because the temperatures of diffusion annealing applied in manufacturing of Nb 3 Sn-based superconducting composites by solid-state diffusion between Nb filaments and bronze matrix (the so-called "bronze" process) fall in it. 53,64) After the annealing at 400°C, 2 h the structure of Nb, processed by 5 and 10 revolutions of HPT, practically does not change. Grain boundaries are still considerably curved, in some grains dislocation density is high, and in some of them the moiré pattern is observed.…”

Section: Effect Of Spd Mode On the Nb Structure Forming Under The Deformation And Following Annealingmentioning

confidence: 99%

Behavior of Nb and Cu–Nb Composites under Severe Plastic Deformation and Annealing

Popov

Попова

2019

Mater. Trans.

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Nowadays potentialities of obtaining bulk nanostructured materials with unique properties by various techniques of severe plastic deformation (SPD) are comprehensively studied, and niobium, being a refractory, but plastic enough metal, is an ideal object for such studies. Besides, niobium is a metal of special interest as an advanced functional material, being one of the main constituents of such important electrotechnical materials as high-strength CuNb composites and multifilamentary Nb 3 Sn-based and NbTi superconductors. The present paper is an overview on evolution of Nb microstructure under SPD via different routes and under large plastic deformation by cold drawing of composite wires (in a Cu matrix). The main attention in this paper is paid to the original studies of the authors (with their coauthors), but the available publications on the topics considered are involved and reviewed as well.

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“…Such a difference in the substitution behavior might affect the Gibbs energy of Nb 3 Sn. However, some reports suggest that the presence of Ti does not lead to a significant change in Nb 3 Sn grain size, compared to no Ti doping [32,33]. It indicates that the substitution by Ti or Ta is unlikely to bring about a substantial impact on the Nb 3 Sn Gibbs energy and thus the nucleation driving force.…”

Section: Discussionmentioning

confidence: 99%

In-depth S/TEM observation of Ti–Hf and Ta–Hf-doped Nb₃Sn layers

Banno,

Moronaga,

Hara

et al. 2024

Supercond. Sci. Technol.

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In superconducting Nb3Sn layers with coherence lengths of approximately 3 nm, grain boundaries act as effective pinning sites. Thus, grain refinement is an essential issue that directly affects the superconducting critical characteristics of the Nb3Sn layer. In recent years, Hf addition to Nb3Sn wires co-doped with Ta has attracted notable interest as a method that enables grain refinement down to several tens of nm. In-depth characterization of the Nb3Sn grain morphology in Hf-doping is crucially important to correlate the microstructure with the flux pinning characteristics. In this article, the grain morphologies of Ti–Hf and Ta–Hf-doped Nb3Sn layers were clarified by scanning transmission electron microscopy (STEM) and TEM-based automated crystal orientation mapping (ACOM-TEM). STEM/energy dispersive X-ray spectroscopy (EDS) revealed no significant oxide precipitates in our samples. The grain size distribution was attained by ACOM-TEM. Although Hf-doping attained a grain refinement effect in the Nb3Sn layer in both doping cases, the degree of this effect was relatively small for Ti–Hf. Kernel average misorientation (KAM) analysis by scanning electron microscopy-electron backscatter diffraction (SEM-EBSD) unveiled no appreciable difference between the internal strain states of the Nb-alloy parent phases in Ti–Hf and Ta–Hf. One remarkable new finding through STEM/EDS was the presence of a Cu–Hf compound phase in the Nb3Sn layer. The Cu–Hf compound sounds analogous to the Cu–Ti compounds that form when Nb–47Ti with Cu matrix is heat treated. The STEM/EDS maps revealed a larger amount of Cu flow from the Cu-Sn side along the grain boundaries. The large Cu deposition on the grain boundaries might facilitate grain growth in Nb3Sn. Those findings make a novel contribution to the literature as they provide a deep insight into Nb3Sn phase formation via Hf doping.

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The Nb3Sn layers formation at diffusion annealing of Ti-doped multifilamentary Nb/Cu–Sn composites

Cited by 37 publications

References 27 publications

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

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

Behavior of Nb and Cu–Nb Composites under Severe Plastic Deformation and Annealing

In-depth S/TEM observation of Ti–Hf and Ta–Hf-doped Nb₃Sn layers

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The Nb3Sn layers formation at diffusion annealing of Ti-doped multifilamentary Nb/Cu–Sn composites

Cited by 37 publications

References 27 publications

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

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

Behavior of Nb and Cu–Nb Composites under Severe Plastic Deformation and Annealing

In-depth S/TEM observation of Ti–Hf and Ta–Hf-doped Nb3Sn layers

Contact Info

Product

Resources

About

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

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

In-depth S/TEM observation of Ti–Hf and Ta–Hf-doped Nb₃Sn layers