Development of high strength and elongation structural material for cryogenic temperature used by characteristic improvement of cryogenic tensile properties by heterogeneous phase structure.

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K14605
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: Kanazawa University
• Principal Investigator: Koga Norimitsu 金沢大学, 機械工学系, 准教授 (30735923)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 構造材料 / 鉄鋼材料 / 引張特性 / 極低温 / 二相鋼 / セレーション

Outline of Final Research Achievements

Duplex steel consisted of ferrite with body-centered cubic structure and austenite with face-centered cubic structure exhibited excellent strength and elongation at low temperatures. Deformation-induced martensitic transformation and simultaneous deformation between ferrite and austenite provided this excellent low-temperature tensile properties. In the duplex steel, grain refinement improves strength and elongation, especially at low temperatures. Duplex steel with fine grain size exhibited a significantly higher strength than that of a conventional steel, while its elongation was approximately equal to conventional steel’s one.

Free Research Field

構造材料

Academic Significance and Societal Importance of the Research Achievements

4.2 Kでの変形では、発熱を伴うセレーションと呼ばれる局所領域の変形によってその機械的性質が変化することが示唆された。本結果は、極低温環境下での金属材料の変形についての基礎的知見を与えるものであり、その学術的意義は深い。一方で、本研究で最終的に得られた二相鋼の4.2 Kでの強度特性は従来材を遥かに凌駕しており、次世代型核融合炉の構造部材になりえる。よって、本成果は、将来的に核融合炉の普及を通して社会に貢献できる可能性を秘めている。