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2015 Fiscal Year Annual Research Report

Ni基高Cr合金の粒界応力腐食割れき裂進展機構解明と保全技術の創成

Research Project

Project/Area Number 25289348
Research InstitutionTohoku University

Principal Investigator

米澤 利夫  東北大学, 未来科学技術共同研究センター, 産学官連携研究員 (10422081)

Co-Investigator(Kenkyū-buntansha) 渡邉 真史  東北大学, 未来科学技術共同研究センター, 准教授 (60312659)
竹田 陽一  東北大学, 工学(系)研究科(研究院), 准教授 (40374970)
Project Period (FY) 2013-04-01 – 2016-03-31
Keywords冷間加工 / 方射光X線 / 加圧水型軽水炉 / 積層欠陥エネルギー / 負傷環境下その場観察 / 応力腐食割れき裂進展機構 / 残留共晶炭化物 / 応力・ひずみ
Outline of Annual Research Achievements

Ni基高CrのTT690合金は、耐応力腐食割れ材料として、世界の加圧水型軽水炉で広く用いられている。しかし近年、一部の研究者から「高度の冷間加工を施したTT690合金は、応力腐食割れき裂進展速度が大きい」との報告がなされ、米国では軽水炉の信頼性維持の観点で大問題となり、国際評価グループが設けられ、その一員である本研究代表者には、TT690合金の応力腐食割れき裂進展に対する抜本的な学術研究を強く求められている。これに対処すべく、本研究では、材料面、応力面、環境面からNi基高Cr合金の粒界応力腐食割れき裂進展機構解明を図り、Ni基高Cr合金の信頼性評価や寿命評価等の保全技術の創成を図ることとした。
平成25年度、26年度で作成した供試材、確立した実験手法(高分解能透過電子顕微鏡による積層欠陥エネルギー値の計測、高性能イオン研磨装置を用いた粒界炭化物の観察、SPring-8の方射光X線による結晶粒界近傍局所の応力ひずみ計測や表面酸化物生成に伴う材料表面残留応力の計測等々)、得られた実験結果、明確になった見解等を基に、平成27年度には、粒界応力腐食割れ挙動に及ぼす材料因子の影響解明や、更なる長時間の応力腐食割れ試験データの取得等を図った。その結果、粒界酸化を加速させる物理要因(溶製時の残留共晶炭化物の酸化による粒界応力腐食割れの促進や、粒界近傍局所の積層欠陥エネルギー値低下による応力腐食割れ進展速度の増大等)を明確にし、応力面からは酸化皮膜生成に伴う引張残留応力の増大や、粒界近傍局所の応力・ひずみの増大を明確にし、環境面からは、腐食環境下その場(In-situ)での酸化挙動を解明し、これらを基に、Ni基高Cr合金の粒界応力腐食割れき裂進展機構解明を、材料、応力、環境面から果たすことができた。それらの成果を多数の論文として発表し、世界のこの種分野の専門家の高い評価を得る事ができた。

Research Progress Status

27年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

27年度が最終年度であるため、記入しない。

Causes of Carryover

27年度が最終年度であるため、記入しない。

Expenditure Plan for Carryover Budget

27年度が最終年度であるため、記入しない。

  • Research Products

    (16 results)

All 2015

All Journal Article (4 results) (of which Peer Reviewed: 4 results,  Open Access: 2 results,  Acknowledgement Compliant: 4 results) Presentation (12 results) (of which Int'l Joint Research: 12 results,  Invited: 5 results)

  • [Journal Article] The Effects of Metallurgical Factors on PWSCC Crack Growth Rates in TT Alloy 690 in Simulated PWR Primary Water2015

    • Author(s)
      Toshio Yonezawa, Masashi Watanabe, Atsushi Hashimoto
    • Journal Title

      Metallurgical and Materials Transactions A

      Volume: Vol.46 Pages: 2766-2780

    • DOI

      10.1007/s11661-015-2852-1

    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Effect of work hardened inner surface layers on stress corrosion cracking of Type 316 stainless steel and TT Alloy 690 in simulated PWR primary water2015

    • Author(s)
      Toshio Yonezawa, Masashi Watanabe, Atsushi Hashimoto
    • Journal Title

      Proceedings of the 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors-

      Volume: - Pages: -

    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] The effects of metallurgical factors on stress corrosion crack growth rate for cold worked TT Alloy 690 in simulated PWR primary water2015

    • Author(s)
      Toshio Yonezawa, Masashi Watanabe, Atsushi Hashimoto
    • Journal Title

      Proceedings of the 17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors-

      Volume: - Pages: -

    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] In Situ X-Ray Diffraction Measurement Method for Investigating the Oxides Films on Austenitic Stainless Steel in Simulated Pressurized Water Reactor Primary Water2015

    • Author(s)
      Masashi Watanabe, Toshio Yonezawa, Takahisa Shobu, and Tesuo Shoji
    • Journal Title

      CORROSION SCIENCE SECTION

      Volume: Vol.71 Pages: 1224-1236

    • DOI

      10.5006/1690

    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Presentation] Study on the Possibility of PWSCC Initiation for TT Alloy 6902015

    • Author(s)
      T.Yonezawa
    • Organizer
      EPRI Alloy 690/52/152 PWSCC Research Collaboration Meeting
    • Place of Presentation
      Tampa, USA
    • Year and Date
      2015-12-01 – 2015-12-04
    • Int'l Joint Research
  • [Presentation] Residual Strain and Dilution Zone of CRDM Tube J-Weld Mock Up2015

    • Author(s)
      T.Yonezawa
    • Organizer
      EPRI Alloy 690/52/152 PWSCC Research Collaboration Meeting
    • Place of Presentation
      Tampa, USA
    • Year and Date
      2015-12-01 – 2015-12-04
    • Int'l Joint Research
  • [Presentation] Policy, Planning and Funding on Material Degradation in Japan2015

    • Author(s)
      T.Yonezawa
    • Organizer
      KAERI
    • Place of Presentation
      DAEJEON, KOREA
    • Year and Date
      2015-11-04 – 2015-11-05
    • Int'l Joint Research / Invited
  • [Presentation] IGSCC (including PWSCC), IASCC of Materials2015

    • Author(s)
      T.Yonezawa
    • Organizer
      KAERI
    • Place of Presentation
      DAEJEON, KOREA
    • Year and Date
      2015-11-04 – 2015-11-05
    • Int'l Joint Research / Invited
  • [Presentation] ODSCC & IGA for SG Tube Materials in Japanese PWRs2015

    • Author(s)
      T.Yonezawa
    • Organizer
      KAERI
    • Place of Presentation
      DAEJEON, KOREA
    • Year and Date
      2015-11-04 – 2015-11-05
    • Int'l Joint Research / Invited
  • [Presentation] Material research activities for Fukushima Dai-ichi NPS after accident2015

    • Author(s)
      T.Yonezawa
    • Organizer
      KAERI
    • Place of Presentation
      DAEJEON, KOREA
    • Year and Date
      2015-11-04 – 2015-11-05
    • Int'l Joint Research / Invited
  • [Presentation] The effect of metallurgical factors on stress corrosion cracking growth rate in simulated PWR primary water for cold worked TT Alloy 6902015

    • Author(s)
      Toshio Yonezawa, Masashi Watanabe, Atsushi Hashimoto
    • Organizer
      17th International Conference on Environmental Degradation of Materials in Nuclear Power Systems- Water Reactors
    • Place of Presentation
      Ottawa, Ontario, Canada
    • Year and Date
      2015-08-09 – 2015-08-13
    • Int'l Joint Research
  • [Presentation] Effects of work hardened inner surface on stress corrosion cracking growth for 316 stainless steel and TT Alloy 690 in Simulated PWR Primary Water2015

    • Author(s)
      Toshio Yonezawa, Masashi Watanabe, Atsushi Hashimoto
    • Organizer
      17th International Conference on Environmental Degradation of Materials in
    • Place of Presentation
      Ottawa, Ontario, Canada
    • Year and Date
      2015-08-09 – 2015-08-13
    • Int'l Joint Research
  • [Presentation] Stress Corrosion Cracking of Austenitic Stainless Steels in High Temperature Water and Alternative Stainless Steel2015

    • Author(s)
      T.Yonezawa
    • Organizer
      11th National Conference on Nuclear Science and Technology
    • Place of Presentation
      Da Nang, Vietnam
    • Year and Date
      2015-08-05 – 2015-08-07
    • Int'l Joint Research / Invited
  • [Presentation] SCCGR evaluation of TT Alloy 690 and its weld metal from the practical view points2015

    • Author(s)
      T.Yonezawa
    • Organizer
      PWSCC CGR Expert Panel Meeting
    • Place of Presentation
      Washington DC,USA
    • Year and Date
      2015-07-14 – 2015-07-15
    • Int'l Joint Research
  • [Presentation] Evaluation on the effect of cold working on SCC initiation and propagation for Alloy 690/52/152 in actual PWR plant2015

    • Author(s)
      T.Yonezawa
    • Organizer
      PWSCC CGR Expert Panel Meeting
    • Place of Presentation
      Washington DC,USA
    • Year and Date
      2015-07-14 – 2015-07-15
    • Int'l Joint Research
  • [Presentation] Effect of work hardened inner surface layers on stress corrosion cracking of 316 stainless steel and TT Alloy 690 in simulated PWR primary water2015

    • Author(s)
      T.Yonezawa, M. Watanabe
    • Organizer
      ICG-EAC Meeting 2015
    • Place of Presentation
      Ann Arbor, USA
    • Year and Date
      2015-05-18 – 2015-05-22
    • Int'l Joint Research

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Published: 2017-01-06  

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