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2004 Fiscal Year Final Research Report Summary

INVESTIGATION TO RETAIN HIGH CRITICAL CURRENT OF COMPOSITE SUPERCONDUCTORS FROM MECHANICAL VIEWPOINT

Research Project

Project/Area Number 14350360
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Composite materials/Physical properties
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

OCHIAI Shojiro  KYOTO UNIVERSITY, INTERNATIONAL INNOVATION CENTER, PROFESSOR, 国際融合創造センター, 教授 (30111925)

Co-Investigator(Kenkyū-buntansha) HOJO Masaki  KYOTO UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING, PROFESSOR, 工学研究科, 教授 (70252492)
OKUDA Hiroshi  KYOTO UNIVERSITY, INTERNATIONAL INNOVATION CENTER, ASSOCIATE PROFESSOR, 国際融合創造センター, 助教授 (50214060)
TANAKA Mototsugu  KYOTO UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING, ASSISTANT PROFESSOR, 工学研究科, 助手 (30346085)
Project Period (FY) 2002 – 2004
KeywordsCOMPOSITE SUPERCONDUCTOR / DEFORMATION / FRACTURE / DAMAGE / CRACK / CRITICAL CURRENT / A15TYPE SUPERCONDUCTOR / HIGH TEMPERATURE OXIDE SUPERCONDUCTOR
Research Abstract

Thermal stresses arising from the difference in thermal expansion among the constituents and tensile/bending stresses are exerted during fabrication and winding. Also Lorentz force is exerted during operation. These stresses are statically and cyclically given to the composite superconductors. Therefore, it is one of the most important research subjects to reveal the mechanical behavior of the composites and its influence on superconducting properties, and, based on such results, to clarify the condition to retain high superconducting properties under applied stresses. The present work attempted to understand the relation of the initiation, growth and accumulation of the stress-induced damages to critical current and to obtain the mechanical condition to retain the original critical current for the multifilamentary Bi_2Sr_2Ca_2Cu_3O_x/Ag (hereafter noted as Bi2223/Ag), Nb_3Al/Cu and Nb-Ti/Cu superconducting composite wires and tapes. Main results are summarized as follows.
Under the sta … More tically applied tensile stresses, the fracture strains of the Bi2223,Nb_3Sn,Nb_3Al and Nb-Ti filaments were around 0.09-0.13,0.5-1.2,0.6-1.0 and 2%, respectively. The rough condition to retain the original critical current is to use the composite superconductors below such strain levels. It is important that the fracture of the filaments can be delayed by introducing residual stresses. In the case of Bi2223 composite with low fracture strain, the introduction of residual stress is very effective. Based on the experiments and analysis, the applied strain is allowable up to around 0.25% which is the sum of the minimum fracture strain and residual stress and applied bending strain up to around 0.4%. Under the cyclic stresses, the fatigue crack initiates in the clad cupper and it propagates to the core region when the stress cycles reaches around 70-90% of the fatigue life. When such situation arises, the critical current is reduced. To retain the original critical current, it is effective to employ the composite superconductors below such stress cycles. Less

  • Research Products

    (22 results)

All 2005 2004 2003 Other

All Journal Article (22 results)

  • [Journal Article] Bending damage evolution and its influence on critical current and n-value of Bi2223/Ag superconducting composite tape2005

    • Author(s)
      D.Doko, S.Ochiai, H.Okuda, M.Tanaka, M.Hojo他5名
    • Journal Title

      Materials Science Forum 475-479

      Pages: 933-936

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Bending damage evolution and its influence on critical current and n-value of Bi2223/Ag superconducting composite tape2005

    • Author(s)
      D.Doko, N.Miyazaki, M.Nakamura, S.Ochiai, H.Okuda, S.S.Oh, M.Tanaka, M.Hojo, K.Osamura
    • Journal Title

      Materials Science Forum Vol.475-479

      Pages: 933-936

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] 多芯Bi2223/Ag/Ag-Mg超伝導複合テープの引張および曲げ破壊挙動とその臨界電流に及ぼす影響2004

    • Author(s)
      落合庄治郎, 奥田浩司, 北條正樹, 田中基嗣他5名
    • Journal Title

      日本金属学会誌 68

      Pages: 681-687

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] In Situ Strain Measurements of in Multifilament Bi2223 Superconducting Filamentary Ag-sheathed Bi2223 Superconducting Tapes2004

    • Author(s)
      H.Okuda, S.Ochiai他5名
    • Journal Title

      Physica C 411

      Pages: 114-119

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Investigation of Mechanical Behavior of Copper in Nb_3Sn Superconducting Composite Wire2004

    • Author(s)
      M.Hojo, M.Tanaka, S.Ochiai他4名
    • Journal Title

      Physica C 412-414

      Pages: 1261-1266

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Damage Evolution under Bending and Tensile Stresses and Its Influence on Critical Current of Bi2223/Ag Superconducting Composite Tape2004

    • Author(s)
      S.Ochiai, N.Miyazaki, D.Doko, T.Nagai, M.Nakamura, H.Okuda, S.S.Oh, M.Hojo, M.Tanaka, K.Osamura
    • Journal Title

      Journal of Nuclear Materials Vol.329-333

      Pages: 1585-1589

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Tensile and Bending Fracture Behavior and Its Influence on Critical Current of Multifilamentary Bi2223/Ag/Ag-Mg Composite Tape2004

    • Author(s)
      S.Ochiai, N.Miyazaki, T.Nagai, D.Doko, H.Okuda, S.S.Oh, M.Hojo, M.Tanaka, K.Osamura
    • Journal Title

      Journal of the Japan Institute of Metals Vol.68

      Pages: 681-687

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] In Situ Strain Measurements of in Multifilament Bi2223 Superconducting Filamentary Ag-sheathed Bi2223 Superconducting Tapes2004

    • Author(s)
      H.Okuda, K.Morishita, S.Ochiai, D.Dokoh, M.Matsui, H.Fujimoto, M.Sato
    • Journal Title

      Physica C Vol.411

      Pages: 114-119

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Investigation of Mechanical Behavior of Copper in Nb_3Sn Superconducting Composite Wire2004

    • Author(s)
      M.Hojo, T.Matsuoka, M.Nakamura, M.Tanaka, T.Adachi, S.Ochiai, K.Miyashita
    • Journal Title

      Physica C Vol.412-414

      Pages: 1261-1266

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Fracture of Filaments and Its Influence on Critical Current and Residual Strength of Fatigued Nb-Ti/Cu Superconducting Composite2003

    • Author(s)
      S.Ochiai, M.Hojo, M.Tanaka, H.Okuda他5名
    • Journal Title

      Cryogenics 43

      Pages: 45-51

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Fatigue Damage Evolution and Damage-induced Reduction of Critical Current of Nb_3Al Superconducting Composite2003

    • Author(s)
      S.Ochiai, M.Hojo, M.Tanaka, H.Okuda他8名
    • Journal Title

      Superconductor Science and Technology 16

      Pages: 1071-1076

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Tensile Damage and Its Influence on Critical Current of Bi2223/Ag Superconducting Composite Tape2003

    • Author(s)
      S.Ochiai, H.Okuda, M.Hojo, M.Tanaka他5名
    • Journal Title

      Superconductor Science and Technology 16

      Pages: 988-994

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Microscopic Fracture of Filaments and Its Relation to the Critical Current under Bending Deformation in (Bi,Pb)_2Sr_2Ca_2Cu_3O_<10> Composite Superconducting Tapes2003

    • Author(s)
      M.Hojo, M.Tanaka, S.Ochiai他5名
    • Journal Title

      Superconductor Science and Technology 16

      Pages: 1043-1051

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Bending Deformation and Its Influence on Critical Current in Bi2223 Comopsite Superconducting Tapes2003

    • Author(s)
      M.Hojo, M.Tanaka, S.Ochiai他4名
    • Journal Title

      Physica C 392-396

      Pages: 1156-1161

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Fracture Damage Evolution and Its Influence on Critical Current of Nb_3Al/Cu and Nb-Ti/Cu Superconducting Composite Wires2003

    • Author(s)
      S.Ochiai, H.Okuda, M.Hojo, M.Tanaka
    • Journal Title

      Recent Research Developments in Materials Science 4

      Pages: 333-353

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Facture of Filaments and Its Influence on Critical Current and Residual Residual Strength of Fatigued Nb-Ti/Cu Superconducting Composite-2003

    • Author(s)
      S.Ochiai, Y.Oki, F.Sekino, M.Hojo, M.Tanaka, H.Okuda, H.Moriai, S.Sasaki, K.Watanabe
    • Journal Title

      Cryogenics Vol.43

      Pages: 45-51

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Fatigue Damage Evolution and Damage-induced Reduction of Critical Current of Nb_3Al Superconducting Composite2003

    • Author(s)
      S.Ochiai, F.Sekino, T.Sawada, H.Ohno, M.Hojo, M.Tanaka, H.Okuda, M.Koganeya, K.Hayashi, Y.Yamada, N.Ayai, K.Watanabe
    • Journal Title

      Superconductor Science and Technology Vol.16

      Pages: 1071-1076

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Tensile Damage and Its Influence on Critical Current of Bi2223/Ag Super-conducting Composite Tape2003

    • Author(s)
      S.Ochiai, T.Nagai, H.Okuda, S.S.Oh, M.Hojo, M.Tanaka, M.Sugano, K.Osamura
    • Journal Title

      Supercondcutor Science and Technology Vol.16

      Pages: 988-994

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Microscopic Fracture of Filaments and Its Relation to the Critical Current under Bending Deformation in (Bi,Pb)_2Sr_2Ca_2Cu_3O_<10> Composite Superconducting Tapes2003

    • Author(s)
      M.Hojo, M.Nakamura, T.Matsuoka, M.Tanaka, S.Ochiai, M.Sugano, K.Osamura
    • Journal Title

      Superconductor Science and Technology Vol.16

      Pages: 1043-1051

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Bending Deformation and Its Influence on Critical Current in Bi2223 Composite Superconducting Tapes2003

    • Author(s)
      M.Hojo, T.Matsuoka, S.Nakaoka, M.Tanaka, S.Ochiai, M.Sugano, K.Osamura
    • Journal Title

      Physica C Vol.392-396

      Pages: 1156-1161

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Fracture Damage Evolution and Its Influence on Critical Current of Nb_3Al/Cu and Nb-Ti/Cu Superconducting Composite Wires2003

    • Author(s)
      S.Ochiai, H.Okuda, M.Hojo, M.Tanaka
    • Journal Title

      Recent Research Developments in Materials Science Vol.4

      Pages: 333-353

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Damage Evolution under Bending and Tensile Stresses and Its Influence on Critical Current of Bi2223/Ag Superconducting Tape

    • Author(s)
      S.Ochiai, H.Okuda, M.Hojo, M.Tanaka 他5名
    • Journal Title

      Journal of Nuclear Materials 329-333

      Pages: 1585-1589

    • Description
      「研究成果報告書概要(和文)」より

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Published: 2006-07-11  

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