High performance new MgB<sub>2</sub>superconducting hollow wires

Giunchi, G.; Ceresara, S.; Ripamonti, G.; DiZenobio, A.; Rossi, Saverio; Chiarelli, S.; Spadoni, M.; Wesche, R.; Bruzzone, Pierluigi

doi:10.1088/0953-2048/16/2/328

Cited by 155 publications

(96 citation statements)

References 20 publications

(24 reference statements)

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“…There are no precise data about the mass density of the reacted MgB 2 layer in IMD processed wires, but very high Vickers microhardness values were reported, of the order of 1300 kg/mm 2 [19]. For comparison, the Vickers microhardness values for bulk samples obtained by high temperature/high pressure treatments are somewhat higher (up to 1500 kg/mm 2 ) [21], thus suggesting a very high mass density (relative mass density > 90%) in IMD filaments, thus confirming the values of Giunchi et al [22]. The value of J c in the reacted MgB 2 layer of IMD wires is higher than for ex situ and in situ wires: J c (4.2K) at 12 T was reported at 4.5 x 10 4 A/cm 2 [19].…”

Section: Mass Densities Fill Factors and J C In Various Mgb 2 Wire Tsupporting

confidence: 83%

“…Considerably higher MgB 2 mass densities were achieved with the internal Mg diffusion (IMD) process [18,19], a modification of the infiltration process [20]. A Mg rod with a diameter of 2.0 mm is placed at the center of a metal tube, the hollow space between the metal sheath inner wall and the Mg rod being filled with a B+SiC powder mixture.…”

Section: Mass Densities Fill Factors and J C In Various Mgb 2 Wire Tmentioning

confidence: 99%

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Technical aspects of cold high pressure densification (CHPD) on long lengths of In Situ MgB2 wires with enhanced Jc values

Flükiger

Hossain

Kulich

et al. 2012

AIP Conference Proceedings

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The technical aspects correlated with the observed enhancement of mass density and critical current density in the filaments of in situ MgB 2 wires by means of the recently developed Cold High Pressure Densification (CHPD) are reviewed. The present analysis first summarizes the results obtained by means of a short sample prototype device with anvil lengths of 39 mm. Pressures well above 1 GPa were applied to short wires, causing J c enhancements between a factor 1.5 and 2.3 at 4.2 K and 8 T. At 20 K, the enhancement is much stronger and reaches a factor 3 for binary and 5 for alloyed MgB 2 wires. Based on these results, an automatic machine has been developed allowing a sequential press/release/advance operation. With this machine, which has been very recently installed at GAP in Geneva, in situ MgB 2 wires of lengths up to 10 meters have so far been successfully densified, confirming the J c enhancements obtained with the short sample device. Using an improved anvil geometry, the wall friction was reduced with respect to the short sample prototype device, thus yielding the same J c enhancements, but at considerably lower applied pressures: now, J c max was obtained at 0.85 GPa, in contrast to values between 1.3 and 1.5 GPa for the short sample device. After densifying at this pressure, the value of J c = 1 x 10 4 A/cm 2 at 4.2 K was obtained at 13.2 T over 1 m length, thus corresponding to an enhancement by a factor 2.2 with respect to the non pressed wire. The present results are promising in view of the application of CHPD to industrial wire lengths.

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Section: Mass Densities Fill Factors and J C In Various Mgb 2 Wire Tsupporting

confidence: 83%

Section: Mass Densities Fill Factors and J C In Various Mgb 2 Wire Tmentioning

confidence: 99%

Technical aspects of cold high pressure densification (CHPD) on long lengths of In Situ MgB2 wires with enhanced Jc values

Flükiger

Hossain

Kulich

et al. 2012

AIP Conference Proceedings

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“…This is confirmed on the macroscopic scale by observations following the formation of MgB 2 in the "internal magnesium diffusion" (IMD) process [51][52][53];…”

Section: Macrostructural Properties: the Reacted Strandmentioning

confidence: 64%

Drawing induced texture and the evolution of superconductive properties with heat treatment time in powder-in-tubein situprocessed MgB₂strands

Susner

Daniels

Sumption

et al. 2012

Supercond. Sci. Technol.

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Monocore powder-in-tube MgB 2 precursor strands were cold-drawn and heat- This effect is attributed to the fibrous macrostructure and its accompanying anisotropic connectivity. Magnetic measurements with the field directed along the strand axis yielded a critical density, J cm ┴ (B), for current flowing transversely to the strand axis that was less than and dropped off more rapidly than J ct (B). In the conventional magnetic measurement, the loop currents that support the magnetization are restricted by the lower of J ct (B) and J cm  (B). In the present case the latter, leading to the premature dropoff of the measured J cm (B) compared to J ct (B) with increasing field. This result is supported byKramer plots of the J cm  (B) and J ct (B) data which lead to an irreversibility field for transverse current that is very much less than the usual transport-measured longitudinal one, B irr,t .

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“…Among the A15 superconductors family, intermetallics in nature, the Nb 3 Sn material, even if very useful for its relatively higher critical temperature (T c = 18 K) and higher critical magnetic field, has an intrinsic brittleness that curbs a wide use of this material. Indeed the brittleness of Nb 3 Sn prevents the drawing operations in the superconducting state and forces its use, in magnet manufacturing, by the "wind-and-react" technique. With the advent of the High Temperature Superconductors (HTS), ceramic in nature, the same issue of the brittleness raised, even if it was mitigated from the introduction of the Powder in Tube (PIT) process.…”

Section: Introductionmentioning

confidence: 99%

“…Some attempt to make industrial-like magnets by the "react-and-wind" process using MgB 2 PIT wires has been also performed [1,2], even if the wires performances, in term of critical currents, were not optimal. An alternative process to the MgB 2 PIT manufacturing is represented by the Liquid Mg Reactive Infiltration (Mg-RLI) process [3], which leads to special hollow wires. The critical current density of this kind of wire is quite high, due to the high density and connectivity of the superconducting material.…”

Section: Introductionmentioning

confidence: 99%

MECHANICAL PROPERTIES OF MgB[sub 2] HOLLOW WIRES

Saglietti¹,

Perini²,

Albisetti³

et al. 2010

AIP Conference Proceedings

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The peculiar morphology of the MgB 2 wires resulting from the reactive liquid Mg infiltration technology (Mg-RLI), characterized by an annular distribution of the superconducting material, originates a peculiar mechanical behaviour. Monofilament wires of different size and different thickness of the superconducting material have been subjected to tensile and flexural deformation, in order to gain a comprehensive description of the mechanical behaviour of the superconducting material. A model based on a simplified description of the mechanical behaviour in term of few parameters aids the interpretation of the various experimental measurements and represents a tool to evaluate the mechanical behaviour of different specifically sized wires. Other variables entering in the mechanical model take into account the filling of the internal hole with the metallic Mg and the strength of the external metallic sheath. The present mechanical analysis gives hints on the limits of applicability of the react-and-wind process in magnet manufacturing with this kind of wires. A further output of the study is to find the variation of the intrinsic mechanical properties of the MgB 2 material as a function of the Carbon doping, obtained via SiC doping.

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High performance new MgB₂superconducting hollow wires

Cited by 155 publications

References 20 publications

Technical aspects of cold high pressure densification (CHPD) on long lengths of In Situ MgB2 wires with enhanced Jc values

Technical aspects of cold high pressure densification (CHPD) on long lengths of In Situ MgB2 wires with enhanced Jc values

Drawing induced texture and the evolution of superconductive properties with heat treatment time in powder-in-tubein situprocessed MgB₂strands

MECHANICAL PROPERTIES OF MgB[sub 2] HOLLOW WIRES

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High performance new MgB2superconducting hollow wires

Cited by 155 publications

References 20 publications

Technical aspects of cold high pressure densification (CHPD) on long lengths of In Situ MgB2 wires with enhanced Jc values

Technical aspects of cold high pressure densification (CHPD) on long lengths of In Situ MgB2 wires with enhanced Jc values

Drawing induced texture and the evolution of superconductive properties with heat treatment time in powder-in-tubein situprocessed MgB2strands

MECHANICAL PROPERTIES OF MgB[sub 2] HOLLOW WIRES

Contact Info

Product

Resources

About

High performance new MgB₂superconducting hollow wires

Drawing induced texture and the evolution of superconductive properties with heat treatment time in powder-in-tubein situprocessed MgB₂strands