Direct measurement of mechanical properties of Bi2223 filament using Ag alloy removed tape

Hojo, Masaki; Hashimoto, Mituru; Tanaka, Mototsugu; Adachi, Taiji; Sugano, M.; Ochiai, Shojiro; Osamura, Kōzō

doi:10.1016/j.physc.2007.03.494

Cited by 3 publications

(2 citation statements)

References 17 publications

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“…The irreversible strain is determined by the thermal residual strain of the superconductor in the composite and the intrinsic fracture strain. In multifilamentary superconducting composites, the residual strain of the superconductor is analytically estimated based on the rule of mixtures to be consistent with the experimental results of the stress-strain curve and the I cstrain behavior [12][13][14]. On the other hand, such an analytical method is unable to be adapted to coated conductors for the following reasons.…”

Section: Introductionmentioning

confidence: 94%

The direct evaluation of the internal strain of biaxially textured YBCO film in a coated conductor using synchrotron radiation

Sugano

Machiya

Osamura³

et al. 2008

Supercond. Sci. Technol.

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The internal strain state of the superconducting film in a coated conductor should be clarified to understand the strain effect on the critical current (Ic). We have developed an in situ strain measurement technique using synchrotron radiation for YBa2Cu3O7−δ (YBCO) coated conductor, and the internal strain of the YBCO film was directly evaluated. YBCO powder obtained from the film in the coated conductor was used as a reference of the zero-strain state. Shifts of the Bragg peaks of the (020) plane of the YBCO film were measured under applied tensile strain, and the internal strain was calculated from the change in the interplanar spacing. The residual strain of the YBCO film in this coated conductor at room temperature (RT) was directly determined to be −0.061%. The fracture strain of the YBCO film was also evaluated from the relationship between the applied strain and the internal strain of YBCO. Surface observation of the coated conductor suggests that fracture initiates in the MgO buffer layer. The irreversible strain (εirr) determined by Ic–strain characteristics at 77 K was compared with the result from in situ strain measurement. The validity of our technique using synchrotron radiation is discussed.

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Section: Introductionmentioning

confidence: 94%

The direct evaluation of the internal strain of biaxially textured YBCO film in a coated conductor using synchrotron radiation

Sugano

Machiya

Osamura³

et al. 2008

Supercond. Sci. Technol.

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“…4, fortunately or unfortunately this is not the case. A subtle residual strain scatter is so results from [2][3][4][5][6][7][8][9][10][11][12][13][14][26][27][28][29][30][31][32] each experiment. Note that the above estimation is a rough one but nonetheless, the achieved σ -ε values from these tests were useful for describing the strain hardening and the pre-compressive force features of this composite wire.…”

mentioning

confidence: 99%

Modulated Rate (Time) – Dependent Strain Hardening of Ag/Bi2223 Composite Wire Flattened in a Low – Strength AgMg Alloy Matrix

Adam¹,

Mele²

2018

ES Mater.Manuf.

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The strain hardening and the pre-compressive forces exerted on the ceramic filaments in Ag/Bi Sr Ca Cu O (BSCCO or Bi -2223 in 2 2 2 3 10+x short) composite wire is analysed and discussed in detail. Tensile stress-strain σ-ε, hardening -relaxation σ(ε(t)) , and the straindependent critical current I (ε) analysis and measurements were carried out on specimen wire at 77 K. An analysis based on fractal C hardening model is presented such that the applied strain starts to exponentially decline at time t = d when normalised σ(t) value equals the value used for the calculation of the composite modulus of elasticity. A biexponential model is further employed over the causally convolved experimental data in order to analyse and compare the relaxation process from both the fractal order and the unnormalised stress range, respectively. Eventually, since the weak metallic part of the composite indicates an abrupt transition from elasticity to direct plasticity, σ-ε data were further analysed by a rate -dependent power -law hardening of the Ramberg -Osgood type. The highest attainable residual strain is therefore used to estimate the intrinsic strain in Bi -2223 filaments when the pre-compressive stress is completely depleted.

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Progress of Evaluation Techniques for Electromagnetic and Mechanical Properties of High Temperature Composite Superconductors

et al. 2009

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Synopsis:Remarkable progresses in the development of high temperature superconductors (HTS) such as BSCCO-2223 tapes and YBCO coated conductors have been achieved in recent years, where very high engineering critical current densities (J e ) were reached in long conductor length. It is however necessary to realize simultaneously high strain tolerance of J e , low AC losses and high mechanical strength in order to apply them for practical uses. In the first part of the present review, some critical techniques to improve microstructures for achieving total performance of BSSCO tapes as well as YBCO coated conductors are suggested. In the major part, the recent progress of evaluation techniques of mecahno-electromagnetic properties is introduced. The HTS's are typical composite material consisting of essentially five components. Here the analytical technique is proposed to make clear the mechanical properties based on the rule of mixture, while the quantitative experimental method to measure tensile properties is introduced. The critical current is very sensitive on strain. The strain dependency could be divided into two regions. In the reversible region, the critical current decreases monotonously for BSCCO tapes. On the other hand, YBCO coated conductors give a so-called Ekin's intrinsic behavior for the change of critical current, where a maximum of critical current appears during the process of increasing tensile strain. In order to understand fully the strain dependences of critical current, it is absolutely necessary to elucidate the strain state exerted on the superconducting component in the composite. Recently the direct measurements of local strain have been succeeded by means of diffraction techniques using neutron and synchrotron radiation. Their interesting results including a new science are reported in the present review.

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Direct measurement of mechanical properties of Bi2223 filament using Ag alloy removed tape

Cited by 3 publications

References 17 publications

The direct evaluation of the internal strain of biaxially textured YBCO film in a coated conductor using synchrotron radiation

The direct evaluation of the internal strain of biaxially textured YBCO film in a coated conductor using synchrotron radiation

Modulated Rate (Time) – Dependent Strain Hardening of Ag/Bi2223 Composite Wire Flattened in a Low – Strength AgMg Alloy Matrix

Progress of Evaluation Techniques for Electromagnetic and Mechanical Properties of High Temperature Composite Superconductors

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