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Formulation of a comprehensive solid-solution-strengthening theory accounting for short-range-order softening

Research Project

Project/Area Number 18K18936
Research Category

Grant-in-Aid for Challenging Research (Exploratory)

Allocation TypeMulti-year Fund
Review Section Medium-sized Section 26:Materials engineering and related fields
Research InstitutionTohoku University

Principal Investigator

OKAMOTO NORIHIKO  東北大学, 金属材料研究所, 准教授 (60505692)

Project Period (FY) 2018-06-29 – 2020-03-31
Project Status Completed (Fiscal Year 2019)
Budget Amount *help
¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2018: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Keywords固溶強化 / 原子変位 / 降伏強度 / 固溶体合金 / 固溶軟化 / 短範囲規則 / 局所格子ひずみ / 第一原理計算 / 強度
Outline of Final Research Achievements

The degree of solid solution strengthening in some high-entropy alloys and binary solid-solution alloys is positively correlated with the average atomic displacement of the constituent elements from the ideal lattice points. However, some binary alloys with short-range ordering are negatively deviated from the linear relationship between the degree of solid solution strengthening and the average atomic displacement derived by assuming a random solid solution, inferring that the short-range order softening could occur in those alloys unlike the traditional short-range order strengthening. We clarified that the degree of short-range ordering strongly affects the average atomic displacement by systematically performing first-principles structural relaxation, and explained the apparent short-range order softening phenomena in some binary solid solution alloys in view of the change in the average atomic displacement due to the short-range ordering.

Academic Significance and Societal Importance of the Research Achievements

身の回りの金属材料のほとんどは,純金属ではなく異種元素が原子レベルで混ざった(固溶体)合金です.異種元素が固溶することによって合金の強度がどの程度高くなるか(固溶強化量)に関して,古くから理論的研究がされてきましたが,単純な合金系や固溶元素濃度が低い場合にしか適用できません.研究代表者らは,固溶強化量を予測し得るユニバーサルな指標として構成元素の結晶格子位置からのずれ(原子変位量)を提案してきましたが,本研究では固溶元素がランダム配列している場合だけでなく,特定の優先的配列をした場合にも固溶強化量の予測指標となりうることを示しました.

Report

(3 results)
  • 2019 Annual Research Report   Final Research Report ( PDF )
  • 2018 Research-status Report
  • Research Products

    (15 results)

All 2019 2018 Other

All Journal Article (4 results) (of which Peer Reviewed: 4 results,  Open Access: 2 results) Presentation (9 results) (of which Int'l Joint Research: 3 results) Remarks (2 results)

  • [Journal Article] Crystal structure of η″-Fe3Al7+x determined by single-crystal synchrotron X-ray diffraction combined with scanning transmission electron microscopy2019

    • Author(s)
      Norihiko L. Okamoto, Masaya Higashi and Haruyuki Inui
    • Journal Title

      Science and Technology of Advanced Materials

      Volume: - Issue: 1 Pages: 543-556

    • DOI

      10.1080/14686996.2019.1613174

    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Structural Change in Hot-Stamped GA Coating and Influence on Corrosion Resistance by Tempering2019

    • Author(s)
      Sengoku Akihiro、Takebayashi Hiroshi、Okamoto Norihiko、Inui Haruyuki
    • Journal Title

      Tetsu-to-Hagane

      Volume: 105 Issue: 8 Pages: 819-826

    • DOI

      10.2355/tetsutohagane.TETSU-2018-155

    • NAID

      130007685238

    • ISSN
      0021-1575, 1883-2954
    • Related Report
      2019 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] 高エントロピー合金の塑性変形挙動と単結晶マイクロピラー圧縮試験法による固溶強化量測定2018

    • Author(s)
      岡本範彦, 乾晴行
    • Journal Title

      日本機械学会誌

      Volume: 121 Pages: 12-15

    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] Atomic Displacement and Strength Properties in Equiatomic High Entropy Alloys with the FCC Structure2018

    • Author(s)
      岡本範彦, 弓削是貴, 乾晴行
    • Journal Title

      Materia Japan

      Volume: 57 Issue: 7 Pages: 312-316

    • DOI

      10.2320/materia.57.312

    • NAID

      130007386651

    • ISSN
      1340-2625, 1884-5843
    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Presentation] Softening by Room Temperature Aging in High Entropy Alloys2019

    • Author(s)
      Norihiko L. Okamoto, Tokujiro Yamamoto, Martin Luckabauer, Hiromu Watanabe, Kouichi Hayashi, Hidemi Kato and Tetsu Ichitsubo
    • Organizer
      Materials Research Society Fall Meeting
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 高エントロピー合金の室温構造緩和2019

    • Author(s)
      岡本 範彦, Martin Luckabauer, 渡辺 宏眸, 山本 篤史郎, 林 好一, 加藤 秀実, 市坪 哲
    • Organizer
      粉体粉末冶金協会第123回講演大会
    • Related Report
      2019 Annual Research Report
  • [Presentation] 無拡散等温ω変態に伴うβ型Ti合金の微細組織および硬度変化2019

    • Author(s)
      岡本 範彦, 笠谷 周平, Martin Luckabauer, 多根 正和, 市坪 哲
    • Organizer
      日本金属学会第165回大会
    • Related Report
      2019 Annual Research Report
  • [Presentation] 高エントロピー合金の室温構造緩和2019

    • Author(s)
      岡本 範彦, Martin Luckabauer, 渡辺 宏眸, 山本 篤史郎, 林 好一, 加藤 秀実, 市坪 哲
    • Organizer
      日本金属学会第165回大会
    • Related Report
      2019 Annual Research Report
  • [Presentation] 高エントロピー合金の特異な室温時効2019

    • Author(s)
      岡本 範彦, Martin Luckabauer, 渡辺 宏眸, 山本 篤史郎, 林 好一, 加藤 秀実, 市坪 哲
    • Organizer
      日本材料学会第5回材料WEEK
    • Related Report
      2019 Annual Research Report
  • [Presentation] Possible Correlation Between Strength and Mean Square Atomic Displacement in Cr-Mn-Fe-Co-Ni High Entropy Alloys2018

    • Author(s)
      Makoto Asakura, Kodai Niitsu, Norihiko L. Okamoto, Koretaka Yuge, Kyosuke Kishida, Haruyuki Inui, Takashi Fukuda, and Tomoyuki Kakeshita
    • Organizer
      Materials Research Society Fall Meeting
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Presentation] Micropillar Compression Deformation of Single-Crystal in CrMnFeCoNi High-Entropy Alloy2018

    • Author(s)
      Norihiko L. Okamoto, Shu Fujimoto, Yuki Kambara, Marino Kawamura, Zhenghao M. Chen, Hirotaka Matsunoshita, Katsushi Tanaka, Haruyuki Inui, and Easo P. George
    • Organizer
      Materials Research Society Fall Meeting
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Presentation] Cr-Mn-Fe-Co-Ni高エントロピー合金の機械特性に及ぼす合金組成の影響2018

    • Author(s)
      浅倉 誠仁, 新津 甲大, 弓削 是貴, 福田 隆, 掛下 知行, 岡本 範彦, 岸田 恭輔, 乾 晴行
    • Organizer
      日本金属学会
    • Related Report
      2018 Research-status Report
  • [Presentation] 高エントロピー合金の室温緩和挙動2018

    • Author(s)
      岡本 範彦, Martin Luckabauer, 渡辺 宏眸, 山本 篤史郎, 林 好一, 加藤 秀実, 市坪 哲
    • Organizer
      日本金属学会
    • Related Report
      2018 Research-status Report
  • [Remarks] 研究代表者個人ホームページ

    • URL

      http://nlokamoto.web.fc2.com/

    • Related Report
      2019 Annual Research Report 2018 Research-status Report
  • [Remarks] 研究代表者所属研究室ホームページ

    • URL

      http://ilab.imr.tohoku.ac.jp/index.html

    • Related Report
      2019 Annual Research Report 2018 Research-status Report

URL: 

Published: 2018-07-25   Modified: 2021-02-19  

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