Bi2Sr2CaCu2O8 + xround wires with Ag/Al oxide dispersion strengthened sheaths: microstructure–properties relationships, enhanced mechanical behavior and reduced Cu depletion

Kajbafvala, Amir; Nachtrab, W.T.; Wong, Terence Kin Shun; Schwartz, J.

doi:10.1088/0953-2048/27/9/095001

Cited by 10 publications

(6 citation statements)

References 41 publications

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“…[8] that contain a Hastelloy C-276 substrate onto which the superconducting film has been deposited have demonstrated an irreversible stress limit under axial tension (σ irr ) as high as 998 MPa at 77 K [9], compared to about 150 MPa for Bi-2223 tapes and Bi-2212 wires with silver alloy matrix [10,11]. Besides critical stress, the irreversible strain limit under axial tension at which the critical current (I c ) degrades (ε irr ) is also an important magnet design parameter, because it determines how much strain the conductor can withstand before failure.…”

Section: Introductionmentioning

confidence: 99%

Effect of monotonic and cyclic axial tensile stress on the performance of superconducting CORC^® wires

Laan

McRae

Weiss

2019

Supercond. Sci. Technol.

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High-current superconducting CORC ® wires, wound from RE-Ba 2 Cu 3 O 7−δ (REBCO) coated conductors, are being developed for use in high-field magnets that would allow operation at magnetic fields exceeding 20 T. The combination of high engineering current densities and high magnetic fields results in large Lorentz forces acting on the CORC ® wire that could cause irreversible degradation to its performance. The effect of axial tensile stress on the critical current of CORC ® wires containing annealed solid copper formers has been measured in liquid nitrogen to determine the irreversible stress limit at which irreversible degradation occurs. The results show no significant change in critical current before the irreversible stress limit is reached, after which the critical current decreases irreversibly with applied stress. The irreversible stress limit as high as 177 MPa depends on the yield strength of the former, the number of superconducting tapes wound into the CORC ® wire and the angle at which the tapes are wound. Although the irreversible stress limit of CORC ® wires is lower than a rudimentary rule of mixtures estimation would suggest, the irreversible strain limit, as high as 0.85%, exceeds that of single REBCO tapes. Both effects are likely the result of the helical fashion in which the REBCO tapes are wound into CORC ® wires. The performance of CORC ® wires was also measured as a function of axial tensile stress fatigue cycling in liquid nitrogen. No significant performance degradation was measured up to 100 000 cycles as long as the peak stress remained below the irreversible stress limit. Only once the peak stress was increased significantly above the irreversible stress limit would the critical current suddenly decrease with stress cycles. The results indicate that CORC ® wires have matured into extremely robust high-current magnet conductors capable of withstanding high levels of axial tensile stress and strain. The irreversible stress limit of CORC ® wires could be increased further by using stronger formers and winding the REBCO tapes at comparable angles, while the irreversible strain limit could potentially be increased by tailoring the winding angle of the REBCO tapes, making CORC ® wires one of the strongest and most elastic high-current superconducting magnet conductors available.

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Section: Introductionmentioning

confidence: 99%

Effect of monotonic and cyclic axial tensile stress on the performance of superconducting CORC^® wires

Laan

McRae

Weiss

2019

Supercond. Sci. Technol.

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“…The increase of mass density, electrical connectivity and critical current density (J C ) induced by overpressure processing has made Bi 2 Sr 2 CaCu 2 O x 8+ (Bi-2212) a credible candidate for solenoids and accelerator magnets able to generate magnetic fields unattainable with low-temperature superconductors [1,2]. Whether Bi-2212 can be preferred to other high-temperature superconductors (HTS) for high-field applications depends also on the mechanical, thermal and electrical stability of the conductor [3][4][5]. The residual-resistivity ratio (RRR) of the normal-metal matrix is a key parameter for both the thermal and the electrical properties.…”

Section: Introductionmentioning

confidence: 99%

Very-high thermal and electrical conductivity in overpressure-processed Bi₂Sr₂CaCu₂O_8+x wires

Bonura

Avitabile

Barth

et al. 2018

Mater. Res. Express

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“…increase T allowable , one can increase either ε irr or the Young's modulus and/or the yielding stress of the Bi-2212 wire by, for example, using an alternative sheath material such as Ag-Al [25,26].…”

Section: Analysis and Discussionmentioning

confidence: 99%

Strain control of composite superconductors to prevent degradation of superconducting magnets due to a quench: I. Ag/Bi₂Sr₂CaCu₂O_xmultifilament round wires

Jaroszyński

et al. 2016

Supercond. Sci. Technol.

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The critical current of many practical superconductors is sensitive to strain, and this sensitivity is exacerbated during a quench that induces a peak local strain which can be fatal to superconducting magnets. Here, a new method is introduced to quantify the influence of the conductor stress and strain state during normal operation on the margin to degradation during a quench, as measured by the maximum allowable hot spot temperature T allowable , for composite wires within superconducting magnets. The first conductor examined is Ag-sheathed Bi 2 Sr 2 CaCu 2 O x round wire carrying high engineering critical current density, J E , of 550 A/mm 2 at 4.2 K and 15 T. The critical axial tensile stress of this conductor is determined to be 150 MPa and, in the absence of Lorentz forces, T allowable is greater than 450 K. With increasing axial tensile stress, ! " , however, T allowable decreases nonlinearly, dropping to 280 K for ! " = 120 MPa and to 160 K for ! " = 145 MPa. T allowable (! ") is shown to be nonlinear and independent of magnetic field from 15 T to 30 T. T allowable (! ") dictates the balance between magnetic field generation, which increases with the magnet operating current and stress, and the safety margin, which decreases with decreasing T allowable , and therefore has important engineering value. It is also shown that T allowable (! ") can be predicted accurately by a general strain model, showing that strain control is the key to preventing degradation of superconductors during a quench.

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Bi₂Sr₂CaCu₂O_{8 + x}round wires with Ag/Al oxide dispersion strengthened sheaths: microstructure–properties relationships, enhanced mechanical behavior and reduced Cu depletion

Cited by 10 publications

References 41 publications

Effect of monotonic and cyclic axial tensile stress on the performance of superconducting CORC^® wires

Effect of monotonic and cyclic axial tensile stress on the performance of superconducting CORC^® wires

Very-high thermal and electrical conductivity in overpressure-processed Bi₂Sr₂CaCu₂O_8+x wires

Strain control of composite superconductors to prevent degradation of superconducting magnets due to a quench: I. Ag/Bi₂Sr₂CaCu₂O_xmultifilament round wires

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Bi2Sr2CaCu2O8 + xround wires with Ag/Al oxide dispersion strengthened sheaths: microstructure–properties relationships, enhanced mechanical behavior and reduced Cu depletion

Cited by 10 publications

References 41 publications

Effect of monotonic and cyclic axial tensile stress on the performance of superconducting CORC® wires

Effect of monotonic and cyclic axial tensile stress on the performance of superconducting CORC® wires

Very-high thermal and electrical conductivity in overpressure-processed Bi2Sr2CaCu2O8+x wires

Strain control of composite superconductors to prevent degradation of superconducting magnets due to a quench: I. Ag/Bi2Sr2CaCu2Oxmultifilament round wires

Contact Info

Product

Resources

About

Bi₂Sr₂CaCu₂O_{8 + x}round wires with Ag/Al oxide dispersion strengthened sheaths: microstructure–properties relationships, enhanced mechanical behavior and reduced Cu depletion

Effect of monotonic and cyclic axial tensile stress on the performance of superconducting CORC^® wires

Effect of monotonic and cyclic axial tensile stress on the performance of superconducting CORC^® wires

Very-high thermal and electrical conductivity in overpressure-processed Bi₂Sr₂CaCu₂O_8+x wires

Strain control of composite superconductors to prevent degradation of superconducting magnets due to a quench: I. Ag/Bi₂Sr₂CaCu₂O_xmultifilament round wires