Allotropic phase transformation by point-defect clustering

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H00309
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Shimane University
• Principal Investigator: Arakawa Kazuto 島根大学, 学術研究院理工学系, 教授 (30294367)
• Co-Investigator(Kenkyū-buntansha): 武藤 哲也 島根大学, 学術研究院理工学系, 准教授 (50312244) ; 大島 義文 北陸先端科学技術大学院大学, 先端科学技術研究科, 教授 (80272699)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 点欠陥 / 転位 / 鉄 / 透過電子顕微鏡

Outline of Final Research Achievements

The purpose of this study was to clarify fundamental issues regarding small point defect clusters, particularly "defect allotropes," using in-situ transmission electron microscopy. The main achievements are as follows: (1) We succeeded in directly observing the formation process of defect allotropes in high-purity iron and a few iron alloys. It was made clear that the formation of defect allotropes is not due to solute or impurity atoms, but is an intrinsic property of iron. (2) We succeeded in directly observing the interactions between dislocation loops and gliding dislocations in iron at room temperature and at high temperatures.

Free Research Field

材料科学

Academic Significance and Societal Importance of the Research Achievements

本研究成果は、点欠陥が導入される多くの過程（原子炉・核融合炉材料における高エネルギー粒子照射、幅広い種類の構造材料における塑性変形 等）における鉄および鉄鋼材料の微細組織変化を理解する上で極めて重要である。「欠陥同素体」を新たな強化因子として生かした新たな鉄鋼材料設計に繋がり得るものと期待される。