Strain scaling law for flux pinning in practical superconductors. Part 1: Basic relationship and application to Nb3Sn conductors

Ekin, John W.

doi:10.1016/0011-2275(80)90191-5

Cited by 383 publications

(231 citation statements)

References 29 publications

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“…In this section the most common parameterizations using consistent notation are applied to the experimental data: the uniaxial power law function proposed by Ekin,20 the values of parameters showing differences between bare and reinforced strand are reported in bold in the following tables.…”

Section: Occurs For This Purpose B C2mentioning

confidence: 99%

Improvement of electromechanical properties of an ITER internal tin Nb3Sn wire

Mondonico

Seeber

Senatore

et al. 2010

Journal of Applied Physics

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The critical current of an internal tin Nb 3 Sn wire developed by Oxford Instruments, Superconducting Technology for International Thermonuclear Experimental Reactor ͑ITER͒ ͑OST type-I, billet No. 7567͒ has been studied under axial strain at fields between 12 and 19 T at 4.2 K. Simulating the situation in a cable in conduit, where thermally induced compressive strain is important, a single wire ͑strand͒ was jacketed with AISI 316L stainless steel. The reinforced wire shows an important increase in m , the applied strain where I c reaches its maximum, from 0.25% to 0.57%. In addition the irreversibility limit, irr , is improved from 0.50% applied strain to Ͼ1.10%. It could also be shown that the I c at zero intrinsic strain is almost identical. This demonstrates that jacketing does not influence the physical parameters of the original wire. Experimental data of the bare wire has been well fitted by different strain functions. However, it was not possible to model the data of the jacketed wire. There are indications that only models which take into account the multidimensional character of strain are able to describe the behavior but further development is required.

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Section: Occurs For This Purpose B C2mentioning

confidence: 99%

Improvement of electromechanical properties of an ITER internal tin Nb3Sn wire

Mondonico

Seeber

Senatore

et al. 2010

Journal of Applied Physics

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“…Currently the main approaches to study the strain dependence are experimental methods [21][22][23] and theoretical analyses. [24][25][26][27][28][29][30] The analytical models have simple theoretical basis, wide applicability, and accurate prediction of performance degradation for some types of strands under simple loads. However, they cannot include the effect of varying n value on transport current and AC loss.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic behaviors of superconducting Nb3Sn wire under a time-dependent current injection

Gao

2014

AIP Advances

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We build a 3D model to analyze the electromagnetic behaviors of Nb3Sn filamentary strand exposed to a time-varying current injection, under the consideration of n value and strain effect. Electromagnetic behaviors, performance degradation and AC loss are investigated. Results show that the filament bundles prevent a further field penetration from the outer shell into the interior matrix. Different current/field profiles occur in the strand and outside. Compared to the critical current, the average transport current keeps a high value with little change over a broader strain range, and has a larger magnitude by several orders of magnitude. Increasing the strain results in a suppression of the current transport capacity, and part of the current is expelled into the metal matrix causing larger AC loss. The larger twist pitch implies a longer current circuit and more magnetic flux enclosed, thus increasing the loss. More details are presented in the paper.

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“…20,34 A third characteristic of wires is the presence of residual strain. Macroscopically, the strain dependence on 0 H K ͑T͒ is well understood in terms of axial strain, [35][36][37] or deviatoric strain, 38,39 but its influence on the complete H-T phase transition is still uncertain. 40 The large Cu matrix enforces a compressive axial strain on the A15 layers due to the larger contraction of the Cu with respect to the A15.…”

Section: Introductionmentioning

confidence: 99%

The upper critical field of filamentary Nb3Sn conductors

Godeke

Jewell

Fischer

et al. 2005

Journal of Applied Physics

104

128

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We have examined the upper critical field of a large and representative set of present multifilamentary Nb 3 Sn wires and one bulk sample over a temperature range from 1.4 K up to the zero-field critical temperature. Since all present wires use a solid-state diffusion reaction to form the A15 layers, inhomogeneities with respect to Sn content are inevitable, in contrast to some previously studied homogeneous samples. Our study emphasizes the effects that these inevitable inhomogeneities have on the field-temperature phase boundary. The property inhomogeneities are extracted from field-dependent resistive transitions which we find broaden with increasing inhomogeneity. The upper 90%-99% of the transitions clearly separates alloyed and binary wires but a pure, Cu-free binary bulk sample also exhibits a zero-temperature critical field that is comparable to the ternary wires. The highest 0 H c2 detected in the ternary wires are remarkably constant: The highest zero-temperature upper critical fields and zero-field critical temperatures fall within 29.5± 0.3 and 17.8± 0.3 K, respectively, independent of the wire layout. The complete field-temperature phase boundary can be described very well with the relatively simple Maki-DeGennes model using a two-parameter fit, independent of composition, strain state, sample layout, or applied critical state criterion.

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Strain scaling law for flux pinning in practical superconductors. Part 1: Basic relationship and application to Nb3Sn conductors

Cited by 383 publications

References 29 publications

Improvement of electromechanical properties of an ITER internal tin Nb3Sn wire

Improvement of electromechanical properties of an ITER internal tin Nb3Sn wire

Electromagnetic behaviors of superconducting Nb3Sn wire under a time-dependent current injection

The upper critical field of filamentary Nb3Sn conductors

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