【公開日：2025.06.10】【最終更新日：2025.05.07】
課題データ / Project Data
課題番号 / Project Issue Number
24KU0109
利用課題名 / Title
Nanostructure analysis in Fe-based alloys by transmission electron microscopy
利用した実施機関 / Support Institute
九州大学 / Kyushu Univ.
機関外・機関内の利用 / External or Internal Use
外部利用/External Use
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-
【重要技術領域 / Important Technology Area】（主 / Main）次世代ナノスケールマテリアル/Next-generation nanoscale materials（副 / Sub）量子・電子制御により革新的な機能を発現するマテリアル/Materials using quantum and electronic control to perform innovative functions
キーワード / Keywords
nanostructure, interface, twin boundary, antiphase boundary
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
Yongmei M. JIN
所属名 / Affiliation
Michigan Technological University,Materials Science and Engineering
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
村上 恭和
利用形態 / Support Type
（主 / Main）共同研究/Joint Research（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
KU-009：ハイコントラスト補助電子顕微鏡
KU-016：低温域観測型・高分解能電子顕微鏡
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
Fe-Pd alloys near 62 at.% Pd exhibit complex diffusional and ordering phase transitions, leading to the formation of intriguing multiphase, multivariant microstructures composed of tetragonal L10 and cubic L12 phases, each possessing distinct magnetic properties. Establishing a direct correlation between magnetic domains and the underlying crystal microstructures in this system is essential for tailoring magnetic behavior through microstructure engineering. In our previous transmission electron microscopy (TEM) studies on Fe-61.8at.%Pd, we investigated the nanoscale interfaces in polytwin microstructures. These studies revealed that the L12 phase forms nanolayers along the twin boundaries of the L10 phase. Furthermore, nanoscale antiphase boundaries (APBs) were observed to facet along {110} planes and exhibit distinct joint structures with varying widths at intersections with twin boundaries. The twin boundary and APB structures in the L10+L12 two-phase microstructure differ significantly from those found in single-phase polytwins in Fe-Pd alloys with slightly lower Pd content. To elucidate the mechanisms of microstructure formation and to further investigate these distinctive nanointerfaces, we extended our TEM studies to Fe-62.2at.%Pd.
実験 / Experimental
Thin-foiled specimens of Fe-62.2at%Pd were prepared by electrochemical polishing in University of Virginia. The microstructure was characterized by using a 200-kV transmission electron microscope, JEM-2100HCKM. Electron diffraction patterns, and dark-field (DF) images were collected.
結果と考察 / Results and Discussion
In Fe-62.2at.%Pd, the microstructure consists of L10 polytwin plates embedded in an L12 matrix. Using electron diffraction and DT-TEM, we identified the tetragonal orientation variants present in the polytwin plates and quantified their volume fractions, and determined the orientations of their habit planes. While the volume fractions of the twin variants remain consistent with those in Fe-61.8at.%Pd, the habit planes change from ~ {100} to ~{111}. We measured the angles between the habit planes and internal twin boundaries within individual polytwin plates, as well as the mutual orientations among multiple polytwin plates. TEM micrographs also reveal systematic changes in the polytwin microstructures as a function of sample thickness, observed when moving away from the center hole. A theoretical analysis based on the invariant habit plane model provides quantitative explanations for these observed microstructure features. Building on these findings, we will perform atomic-resolution characterization of the interfacial structures in Fe-62.2at.%Pd and compare with those in Fe-61.8at.%Pd. This will be followed by magnetic characterization using Lorentz microscopy and electron holography to establish the correlation between microstructure and magnetic domain configurations.
図・表・数式 / Figures, Tables and Equations
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
-
Yuto Tomita, Magnetic Domain Observations in the Polytwin Microstructure of Fe-61.8 at.% Pd, Magnetic Domain Observations in the Polytwin Microstructure of Fe-61.8 at.% Pd, , (2025).
DOI: 10.14293/APMC13-2025-0202
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
- 富田 雄人,玉岡 武泰,村上 恭和,M.ヨンメイ ジン,”双晶構造を持つFe-61.8at.%Pd合金の磁区構造観察”日本金属学会2024年秋季講演大会,2024年9月18日
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件