Effect of Nb orientation and deformation on the growth of Nb<sub>3</sub>Sn intermetallic superconductor by bronze technique

Santra, Sangeeta; Suwas, Satyam; Paul, Aloke

doi:10.1080/09500839.2015.1112045

Cited by 9 publications

(2 citation statements)

References 19 publications

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“…Most of the intermetallic compounds in various systems grow with large grains covering the thickness from one interface to the Kirkendall marker plane or one interface to another (if the Kirkendall marker plane is not present or it is present very close to one of the interfaces[18]). However, there are few systems[19,20], in which grains in a particular sublayer of intermetallic phase grow with many smaller grains indicating the ease of nucleation similar to what we have found between interface I and K 1 . In a previous study based on the TEM…”

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confidence: 82%

Bifurcation of the Kirkendall marker plane and the role of Ni and other impurities on the growth of Kirkendall voids in the Cu–Sn system

et al. 2017

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The presence of bifurcation of the Kirkendall marker plane, a very special phenomenon discovered recently, is found in a technologically important Cu-Sn system. It was predicted based on estimated diffusion coefficients; however, could not be detected following the conventional inert marker experiments. As reported in this study, we could detect the locations of these planes based on the microstructural features examined in SEM and TEM. This strengthens the concept of the physico-chemical approach that relates microstructural evolution with the diffusion rates of components and imparts finer understanding of the growth mechanism of phases. The estimated diffusion coefficients at the Kirkendall marker planes indicates that the reason for the growth of the Kirkendall voids is the nonconsumption of excess vacancies which are generated due to unequal diffusion rate of components. Systematic experiments using different purity of Cu in this study indicates the importance of the presence of impurities on the growth of voids, which increases drastically for ≥ 0.1 wt.% impurity. The growth of voids increases drastically for electroplated Cu, commercially pure Cu and Cu(0.5 at.%Ni) indicating the adverse role of both inorganic and organic impurities. Void size and number distribution analysis indicates the nucleation of new voids along with the growth of existing voids with the increase in annealing time. The newly found location of the Kirkendall marker plane in the Cu 3 Sn phase indicates that voids grow on both the sides of this plane which was not considered earlier for developing theoretical models.

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Bifurcation of the Kirkendall marker plane and the role of Ni and other impurities on the growth of Kirkendall voids in the Cu–Sn system

et al. 2017

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“…Optimization of Nb 3 Sn for superconducting applications hinges on achieving ideal grain boundary behavior. Grain boundaries in Nb 3 Sn are fundamental for growing the material itself [5,6,[37][38][39], and prevailing limitations spotlight differing roles of grain boundaries in dc vs. ac applications. In dc applications such as superconducting wires, high grain boundary densities provide needed pinning centers to prevent vortices from limiting the critical current density [4,40,41].…”

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confidence: 99%

Ab initio theory of the impact of grain boundaries and substitutional defects on superconducting Nb₃Sn

Kelley

Sitaraman²,

Arias³

2020

Supercond. Sci. Technol.

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Grain boundaries play a critical role in superconducting applications of Nb3Sn: in dc applications, grain boundaries preserve the material’s inherently high critical current density by pinning flux, while in ac applications grain boundaries can provide weak points for flux entry leading to significant dissipation. We present the first ab initio study to investigate the physics of different grain boundary types in Nb3Sn and their impact on superconductivity using density-functional theory. We identify an energetically favorable selection of high-angle tilt and twist grain boundaries of distinct orientations. We find that clean grain boundaries free of point defects reduce the Fermi-level density of states by a factor of two, an effect that decays back to the bulk electronic structure ∼1–1.5 nm from the boundary. We further calculate the binding free-energies of tin substitutional defects to multiple boundaries, finding a strong electronic interaction that extends to a distance comparable to that of the reduction of density of states. Associated with this interaction, we discover a universal trend in defect electronic entropies near a boundary. We then probe the effects of defect segregation on grain boundary electronic structure and calculate the impact of substitutional impurities on the Fermi-level density of states in the vicinity of a grain boundary. We find that titanium and tantalum defects have little impact regardless of placement, whereas tin, copper, and niobium defects each have a significant impact but only on sites away from the boundary core. Finally, we introduce a model for a local superconducting transition temperature and consider how grain boundary composition affects T c as a function of distance from the boundary plane. The methodology established in this manuscript can be applied to other A15 superconductors in addition to Nb3Sn.

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Composition-Dependent Thermodynamic Factor and Tracer Diffusion of A15-V3Ga Intermetallic Compound

Srivastava,

Santra

2023

Metall Mater Trans A

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Effect of Nb orientation and deformation on the growth of Nb₃Sn intermetallic superconductor by bronze technique

Cited by 9 publications

References 19 publications

Bifurcation of the Kirkendall marker plane and the role of Ni and other impurities on the growth of Kirkendall voids in the Cu–Sn system

Bifurcation of the Kirkendall marker plane and the role of Ni and other impurities on the growth of Kirkendall voids in the Cu–Sn system

Ab initio theory of the impact of grain boundaries and substitutional defects on superconducting Nb₃Sn

Composition-Dependent Thermodynamic Factor and Tracer Diffusion of A15-V3Ga Intermetallic Compound

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Effect of Nb orientation and deformation on the growth of Nb3Sn intermetallic superconductor by bronze technique

Cited by 9 publications

References 19 publications

Bifurcation of the Kirkendall marker plane and the role of Ni and other impurities on the growth of Kirkendall voids in the Cu–Sn system

Bifurcation of the Kirkendall marker plane and the role of Ni and other impurities on the growth of Kirkendall voids in the Cu–Sn system

Ab initio theory of the impact of grain boundaries and substitutional defects on superconducting Nb3Sn

Composition-Dependent Thermodynamic Factor and Tracer Diffusion of A15-V3Ga Intermetallic Compound

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Product

Resources

About

Effect of Nb orientation and deformation on the growth of Nb₃Sn intermetallic superconductor by bronze technique

Ab initio theory of the impact of grain boundaries and substitutional defects on superconducting Nb₃Sn