Local Lattice Strain around Alloying Element and Martensitic Transformation in Titanium and Iron Alloys

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04991
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26010:Metallic material properties-related
• Research Institution: Nagoya Industrial Science Research Institute
• Principal Investigator: Morinaga Masahiko 公益財団法人名古屋産業科学研究所, 研究部, 研究員 (50126950)
• Co-Investigator(Kenkyū-buntansha): 吉野 正人 名古屋大学, 工学研究科, 助教 (10397466) ; 湯川 宏 名古屋大学, 工学研究科, 助教 (50293676)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: チタン / 鉄 / マルテンサイト変態 / 局所格子歪 / 擬ポテンシャル / 合金設計

Outline of Final Research Achievements

It is well known that local strains are introduced into the crystal lattice around a solute atom, M, due to the size mismatch between solute and solvent atoms in any alloy. In this study, local lattice strains are calculated for the first time in both binary Ti and Fe alloys,using the pseudopotential method.
The calculated local lattice strains are found to vary largely with M and the crystal structures. Also, there is a certain correlation between the martensite start temperature (Ms) and the local lattice strains introduced around M. Such local lattice strains work to suppress the onset of the martensitic transformation in both Ti and Fe alloys.

Free Research Field

金属材料・物性

Academic Significance and Societal Importance of the Research Achievements

合金中の種々の合金元素近傍の局所格子歪の大きさを系統的に決定した最初の学術研究である。また、マルテンサイト変態は金属材料学の中核をなす変態であり、本研究成果は、実用上も重要な鉄合金やチタン合金の設計と開発を行う上で重要な知見を与える。