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Enhancement of ductility by controlling three dimensional structure and retained austenite in steels

Research Project

Project/Area Number 17H04958
Research Category

Grant-in-Aid for Young Scientists (A)

Allocation TypeSingle-year Grants
Research Field Material processing/Microstructural control engineering
Research InstitutionThe University of Tokyo

Principal Investigator

Nambu Shoichi  東京大学, 大学院工学系研究科(工学部), 准教授 (00529654)

Research Collaborator KOSEKI toshihiko  
Project Period (FY) 2017-04-01 – 2019-03-31
Project Status Completed (Fiscal Year 2018)
Budget Amount *help
¥21,840,000 (Direct Cost: ¥16,800,000、Indirect Cost: ¥5,040,000)
Fiscal Year 2018: ¥7,540,000 (Direct Cost: ¥5,800,000、Indirect Cost: ¥1,740,000)
Fiscal Year 2017: ¥14,300,000 (Direct Cost: ¥11,000,000、Indirect Cost: ¥3,300,000)
Keywords鉄鋼材料 / オーステナイト / その場観察 / 結晶塑性有限要素法 / 加工誘起マルテンサイト変態 / 3次元組織観察 / 組織制御 / 延性 / マルテンサイト / 強度
Outline of Final Research Achievements

In order to achieve more improved strength and ductility combinations of new multi-phase steels with 3-dimensional continuous complicated structure, the microstructural morphology in the 3-dimensional structures was evaluated, and the relationship between the microstructure and mechanical properties was examined. By observing the 3-dimensional structure of martensite, it was shown that the effect of boundary planes on the microstructure is large in the early stage of the transformation. In addition, an in-situ observation and a stress field analysis using crystal plasticity finite element model were conducted for the deformation-induced martensite transformation of retained austenite, and it was demonstrated that the position where the deformation-induced martensite transformation onsets can be estimated.

Academic Significance and Societal Importance of the Research Achievements

3次元の組織形態評価は近年の測定装置の精度向上によってようやく評価可能になった研究領域であり,この評価技術によって得られる組織と力学特性の関連性を明確にすることは,鉄鋼材料に限らず今後の新規材料開発においても重要な役割を果たすと考えられる。また,残留オーステナイトの制御は,材料の加工硬化率を制御するという点において産業的に非常に重要であることに加えて,複雑応力場でのマルテンサイト変態の理解や結晶塑性有限要素法によるマルテンサイト変態挙動の予測は科学的にも非常に有益であると考えられる。

Report

(3 results)
  • 2018 Annual Research Report   Final Research Report ( PDF )
  • 2017 Annual Research Report
  • Research Products

    (11 results)

All 2018 2017

All Presentation (11 results) (of which Int'l Joint Research: 8 results,  Invited: 2 results)

  • [Presentation] Phase transformation and microstructure in steel welds2018

    • Author(s)
      S. Nambu, T. Koseki
    • Organizer
      6th International Conference on Recent Advances in Materials, Minerals and Environment
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Crystallographic study of bainite transformation from various hetero-phase boundaries2018

    • Author(s)
      Y. Aisu, S. Nambu, T. Koseki
    • Organizer
      6th International Conference on Recent Advances in Materials, Minerals and Environment
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Three-dimensional analysis of martensitic transformation in steel2018

    • Author(s)
      S. Higuchi, S. Nambu, T. Koseki
    • Organizer
      6th International Conference on Recent Advances in Materials, Minerals and Environment
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Numerical Analysis of microstructure influence on the performance of TRIP steels2018

    • Author(s)
      C. Corthier, S. Nambu, T. Koseki
    • Organizer
      6th International Conference on Recent Advances in Materials, Minerals and Environment
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Bainite transformation from austenite grain boundary in medium carbon steels2018

    • Author(s)
      S. Jimbo, R. Hattori, S. Nambu
    • Organizer
      6th International Conference on Recent Advances in Materials, Minerals and Environment
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research
  • [Presentation] In-situ observation of transformation behavior of lath martensite in steels with various strength of austenite2017

    • Author(s)
      S. Nambu、 T. Moriguchi、 T. Koseki
    • Organizer
      International Conference on Martensitic Transformations
    • Related Report
      2017 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Development of structural materials with improved properties2017

    • Author(s)
      S. Nambu、 T. Koseki
    • Organizer
      International Symposium on Innovative Process Design for Structural Materials
    • Related Report
      2017 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Variant selection in primary and secondary nucleation of bainite in steels with various carbon contents2017

    • Author(s)
      S. Nambu、 R. Hattori、 M. Ojima、 T. Koseki
    • Organizer
      Materials Science & Technology 2017 Conference & Exhibition
    • Related Report
      2017 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 中・高炭素鋼における粒界から生成したベイナイトの結晶学的解析2017

    • Author(s)
      南部将一、服部涼介、小島真由美、小関敏彦
    • Organizer
      日本鉄鋼協会第174回秋季講演大会
    • Related Report
      2017 Annual Research Report
  • [Presentation] 鋼中の酸化物からのベイナイト変態の結晶学的検討2017

    • Author(s)
      愛須優輝、南部将一、小関敏彦
    • Organizer
      日本鉄鋼協会第174回秋季講演大会
    • Related Report
      2017 Annual Research Report
  • [Presentation] 高炭素鋼中の残留オーステナイトの加工誘起変態挙動2017

    • Author(s)
      北川冬馬、南部将一、小関敏彦
    • Organizer
      日本鉄鋼協会第174回秋季講演大会
    • Related Report
      2017 Annual Research Report

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Published: 2017-04-28   Modified: 2020-03-30  

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