Structure-property relation of higher-ordered structures - Control of nanostructure for materials properties in Al5Fe2

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K18825
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Kyoto University
• Principal Investigator: INUI HARUYUKI 京都大学, 工学研究科, 教授 (30213135)
• Co-Investigator(Kenkyū-buntansha): 岸田 恭輔 京都大学, 工学研究科, 准教授 (20354178) ; 陳 正昊 京都大学, 工学研究科, 助教 (20889109)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: 高次規則構造 / 結晶構造 / 部分占有 / 構造物性 / 溶融アルミめっき鋼板 / 相変態 / 電子顕微鏡法 / X線回折

Outline of Final Research Achievements

In addition to the previously reported orthorhombic phase, we have found many higher-ordered phases for Al5Fe2, which is industrially very important as the major constituent phase in the coating layer of hot-dip aluminized steel. The crystal structure of the previously reported orthorhombic Al5Fe2 phase consists of the network structure of the Al2Fe stoichiometry and the partially-occupied Al-site chains, in which 6 consecutive Al2 and Al3 sites that are allowed to be occupied by Al atoms are aligned along the c-axis. A series of higher-ordered phases are found to form with some ordered arrangements of Al and Fe atoms in the partially-occupied Al-site chains parallel to the c-axis. The crystal structures of four different higher-ordered phases for Al5Fe2 have been refined and the origin of differences in deformability has been elucidated.

Free Research Field

材料物性

Academic Significance and Societal Importance of the Research Achievements

一連の「高次規則相」は，Al5Fe2相の固溶範囲内では化合物の密度は大きく変化しないという知見から，高次規則構造は，c軸チェーンサイト内でのAlおよびFe部分占有原子の高次規則配列によるもので，この高次規則配列がFe/Al濃度，温度によりどのように決定されるか，その規則配列によってどのように物性が変化するのか実験的に評価する点に高い創造性があり，学術的意義がある．また，高次規則構造の制御により，Al5Fe2相金属間化合物に物性・特性の改善の可能性に繋がり，我が国発の独自技術である溶融アルミメッキ鋼板の脆化抑制に応用できる技術に直結する成果が上げられる可能性が高く，社会的意義も高いといえる．