【公開日：2024.07.25】【最終更新日：2024.03.31】

課題データ / Project Data

課題番号 / Project Issue Number

23KT0002

利用課題名 / Title

Ti基固溶体合金における高温組織変化のその場観察

利用した実施機関 / Support Institute

京都大学 / Kyoto Univ.

機関外・機関内の利用 / External or Internal Use

内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)

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）マテリアルの高度循環のための技術/Advanced materials recycling technologies（副 / Sub）マルチマテリアル化技術・次世代高分子マテリアル/Multi-material technologies / Next-generation high-molecular materials

キーワード / Keywords

電子顕微鏡/ Electronic microscope,資源使用量低減技術/ Technologies for reducing resource usage,電子回折/ Electron diffraction,ハイエントロピー材料/ High entropy material

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)

吉田 周平

所属名 / Affiliation

京都大学大学院 工学研究科

共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes

Guo Baoqi

ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes

清村 勤

利用形態 / Support Type

（主 / Main）機器利用/Equipment Utilization（副 / Sub）,技術補助/Technical Assistance

利用した主な設備 / Equipment Used in This Project

KT-403：モノクロメータ搭載低加速原子分解能分析電子顕微鏡

報告書データ / Report

概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)

Experimental studies on phase transformation from alpha-HCP phase to beta-BCC phase in Ti and its alloys is limited to ex-situ observations in which microstructure is observed at room temperature after rapid cooling. However, during cooling, beta phase transformed to martensite or alpha phase. Thus, it is very difficult to understand the mechanisms of real-time phase transformations though conventional ex-situ techniques. To solve this problem, we used transmission electron microscopy (TEM) with a heating specimen stage to study the phase transformation from alpha to beta in real-time. 

実験 / Experimental

Pure Ti was firstly heavily deformed by a high-pressure torsion process at room temperature and annealed at 800°C for 3 min so that fine grains can be obtained. The samples with fine grains were introduced to TEM (ARM-200F) with a heating specimen holder. The accelerated voltage was 200 kV. The sample was supposed to be heated to temperatures ranging from 900°C to 950°C with the heating rate of 0.5 °C / s. Diffraction contrast images of the microstructure and selective area diffraction patterns were continuously taken to observe the microstructural change during the phase transformation．

結果と考察 / Results and Discussion

　The initial microstructure prior to heating (Fig. 1) showed that the several grains were detected with clear grain boundaries. After heating to 600 °C, the temperature could not be increased anymore due to the technical issues of the heating system. Accordingly, phase transformation was not observed in the sample. The transus temperature of pure Ti is approximately 882 °C. In order to activate the phase transformation from alpha to beta during heating, the temperature needs to be greater than 882 °C. 

図・表・数式 / Figures, Tables and Equations

Initial microstructural state of pure Ti at room temperature.

その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)

This work was supported by JSPS KAKENHI Grant-in-Aid for Early-Career Scientists (JP22K14501). Also, the technical assistance of Dr. Tsutomu Kiyomura of Kyoto University is highly acknowledged.

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)

口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.

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