The mechanical deformation of superconducting BiSrCaCuO/Ag composites

Han, Z.; Skov-Hansen, P.; Freltoft, T.

doi:10.1088/0953-2048/10/6/001

Cited by 106 publications

(74 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, for multifilamentary conductors with composite metal sheaths, we must consider more for J c performance due to their complex architecture and very small filament size. For BiSrCaCuO/Ag multifilamentary wires and tapes, microhardness were widely used to indicate the variations of mass density for filaments in different locations on transverse cross section, and provided a connection between deformation methods/parameters and J c distribution [25][26][27][28][29][30]. On the other hand, structural uniformity of BiSrCaCuO filaments along the longitudinal direction is also an important issue that must be taken into consideration.…”

mentioning

confidence: 99%

Critical current density and microstructure of iron sheathed multifilamentary Sr1−xKxFe2As2/Ag composite conductors

Yao

Lin

Zhang

et al. 2015

Journal of Applied Physics

View full text Add to dashboard Cite

Iron-based superconductors have been considered to be very promising in high-field applications, for which multifilamentary wire and tape conductors with high mechanical strength are essential. In this work, 7-， 19-and 114-filament Sr 0.6 K 0.4 Fe 2 As 2 (Sr-122) superconducting wires and tapes with silver as matrix and iron as outer reinforcing sheath were produced by the ex situ powder-in-tube method.The mass densities of Sr-122 phase in 7-and 19-filament conductors were investigated by microhardness characterization, which revealed a positive correlation Author to whom any correspondence should be addressed.

show abstract

mentioning

confidence: 99%

Critical current density and microstructure of iron sheathed multifilamentary Sr1−xKxFe2As2/Ag composite conductors

Yao

Lin

Zhang

et al. 2015

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The sausaging occurs during the cold-working as a result of large differences of hardness between the filament cores and the sheath [36].…”

mentioning

confidence: 99%

“…Table I attributable to the increase in the hardness of sheath materials [36,37]. Furthermore, the uniform Ag/superconductor interface can improve the degree of local texture of the superconducting grains [38].…”

mentioning

confidence: 99%

High transportJ_cin magnetic fields up to 28 T of stainless steel/Ag double sheathed Ba122 tapes fabricated by scalable rolling process

Gao

Togano

Matsumoto

et al. 2014

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Abstract:The recently discovered iron-based superconductors with very high upper critical field (H c2 ) and small anisotropy have been regarded as a potential candidate material for high field applications. However, enhancements of superconducting properties are still needed to boost the successful use of iron-based superconductors in such applications. Here, we propose a new sheath architecture of stainless steel (SS)/Ag double sheath and investigate its influence on the microstructures and J c -H property.We found that the transport J c -H curves for rolled and pressed tapes both show extremely small magnetic field dependence and exceed 3×10 4 A/cm 2 under 28 T, which are much higher than those of low-temperature superconductors. More interestingly, 12 cm long rolled tape shows very high homogeneity and sustains J c as high as 7.7×10 4 A/cm 2 at 10 T. These are the highest values reported so far for iron-based superconducting wires fabricated by scalable rolling process. The microstructure investigations indicate that such high J c was achieved by higher density of the core and uniform deformation resulting better texturing. These results indicate that our process is very promising for fabricating long Ba122 wires for high field magnet, i.e. above 20 T.* Author to whom correspondence should be addressed; E-mail: KUMAKURA.Hiroaki@nims.go.jp 2The recently discovered iron-based superconductors have attracted great interest as a subject of both fundamental study and practical applications [1][2][3][4][5][6][7][8][9]. Among the various iron based superconductors, 122-type (AE)Fe 2 As 2 (AE = Sr, Ba) is very attractive for high field applications due to its excellent properties such as very high upper critical field (H c2 ), relatively small anisotropy [10,11], and an advantageous grain-boundary nature [12]. In order to achieve high critical current density (J c ) various processing techniques have been used [13][14][15][16][17][18]. Among these proposed processes, the powder-in-tube (PIT) method seems the most promising technique for practical applications [19][20][21]. Thus, the Ba(Sr)122 PIT wires have been investigated intensively [22][23][24][25][26][27][28][29][30][31], and high J c exceeding the level of 10 4 A/cm 2 at 4.2 K and 10 T has been reported for short samples prepared by applying uniaxial pressing [32][33][34][35].However, unfortunately, pressing processes are usually applicable only for a short sample and it is difficult to attain such high J c values with good reproducibility. For practical applications, it is desirable if high J c values are attained with good reproducibility by rolling, which is easy to scale up to the long length wire production.Although silver looks the most suitable sheath material for 122 phase, there are a number of drawbacks of using pure Ag as the sheathing material: poor mechanical properties after the heat treatment that make the coil winding difficult and limit its ability to support Lorentz forces in high magnetic fields, and high occurrence of sausaging during mechan...

show abstract

“…The fewer, smaller and perhaps pure O 2 bubbles formed in the melt allowed the critical current I c (4.2 K, 5 T) to be doubled. CIPping needs a pressure at least 65 MPa to achieve higher packing density, since the yield strength of pure silver is about 65 MPa [27], [28]. Silver alloy sheath is normally used for Bi-2212 conductors for better strength, so that pressure much higher than 65 MPa is needed for CIPping.…”

mentioning

confidence: 99%

Reduction of Gas Bubbles and Improved Critical Current Density in Bi-2212 Round Wire by Swaging

Jiang

Miao²,

Huang³

et al. 2013

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

Bi-2212 round wire is made by the powder-in-tube technique. An unavoidable property of powder-in-tube conductors is that there is about 30% void space in the as-drawn wire. We have recently shown that the gas present in the as-drawn Bi-2212 wire agglomerates into large bubbles and that they are presently the most deleterious current limiting mechanism. By densifying short 2212 wires before reaction through cold isostatic pressing (CIPping), the void space was almost removed and the gas bubble density was reduced significantly, resulting in a doubled engineering critical current density (J E ) of 810 A/mm 2 at 5 T, 4.2 K. Here we report on densifying Bi-2212 wire by swaging, which increased J E (4.2 K, 5 T) from 486 A/mm 2 for asdrawn wire to 808 A/mm 2 for swaged wire. This result further confirms that enhancing the filament packing density is of great importance for making major J E improvement in this roundwire magnet conductor. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Abstract-Bi-2212 round wire is made by the powder-in-tube technique. An unavoidable property of powder-in-tube conductors is that there is about 30% void space in the as-drawn wire. We have recently shown that the gas present in the asdrawn Bi-2212 wire agglomerates into large bubbles and that they are presently the most deleterious current limiting mechanism. By densifying short 2212 wires before reaction through cold isostatic pressing (CIPping), the void space was almost removed and the gas bubble density was reduced significantly, resulting in a doubled engineering critical current density (J E ) of 810 A/mm 2 at 5 T, 4.2 K. Here we report on densifying Bi-2212 wire by swaging, which increased J E (4.2 K, 5 T) from 486 A/mm 2 for as-drawn wire to 808 A/mm 2 for swaged wire. This result further confirms that enhancing the filament packing density is of great importance for making major J E improvement in this round-wire magnet conductor.

show abstract

The mechanical deformation of superconducting BiSrCaCuO/Ag composites

Cited by 106 publications

References 50 publications

Critical current density and microstructure of iron sheathed multifilamentary Sr1−xKxFe2As2/Ag composite conductors

Critical current density and microstructure of iron sheathed multifilamentary Sr1−xKxFe2As2/Ag composite conductors

High transportJ_cin magnetic fields up to 28 T of stainless steel/Ag double sheathed Ba122 tapes fabricated by scalable rolling process

Reduction of Gas Bubbles and Improved Critical Current Density in Bi-2212 Round Wire by Swaging

Contact Info

Product

Resources

About

The mechanical deformation of superconducting BiSrCaCuO/Ag composites

Cited by 106 publications

References 50 publications

Critical current density and microstructure of iron sheathed multifilamentary Sr1−xKxFe2As2/Ag composite conductors

Critical current density and microstructure of iron sheathed multifilamentary Sr1−xKxFe2As2/Ag composite conductors

High transportJcin magnetic fields up to 28 T of stainless steel/Ag double sheathed Ba122 tapes fabricated by scalable rolling process

Reduction of Gas Bubbles and Improved Critical Current Density in Bi-2212 Round Wire by Swaging

Contact Info

Product

Resources

About

High transportJ_cin magnetic fields up to 28 T of stainless steel/Ag double sheathed Ba122 tapes fabricated by scalable rolling process