【公開日：2023.08.01】【最終更新日：2023.05.08】
課題データ / Project Data
課題番号 / Project Issue Number
22KT0023
利用課題名 / Title
The characterization of carbide in annealed high chromium cast irons using TEM and EELS
利用した実施機関 / Support Institute
京都大学
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）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（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
TEM, EDS, EELS,電子顕微鏡/Electron microscopy,集束イオンビーム/Focused ion beam,表面・界面・粒界制御/ Surface/interface/grain boundary control,異種材料接着・接合技術/ Dissimilar material adhesion/bonding technology
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)
Wiengmoon Amporn
所属名 / Affiliation
Department of Physics, Faculty of Science, Naresuan University
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
Kittikhun Ruangchai
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
山口 睦,清村 勤,治田 充貴
利用形態 / Support Type
（主 / Main）技術代行/Technology Substitution（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
KT-402：球面収差補正透過電子顕微鏡
KT-404：集束イオンビーム装置
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
The as-cast microstructure of the 22-30wt.%Cr and 2.0-2.7wt.%C high chromium cast irons (HCCIs) consists of primary austenite dendrites and eutectic M7C3 carbide. Properties of these irons can be improved by alloying and heat treatments. In particular applications, annealing treatment is necessary for machining operations. There are few reports on the morphology of secondary carbides forming after annealing in high chromium cast iron and investigation of these carbides by TEM is limited. The aim of this research is to use TEM for studying carbides formed by annealing of 28wt.%Cr cast irons. A preliminary EELS examination of the carbides will also be studied.
実験 / Experimental
As-cast specimens of the 28wt.%Cr (R), 28wt.%Cr-1wt.%Mo (Mo1) and 28wt.%Cr-1wt.%W (W1) irons were annealed at 800oC for 4 h, followed by slow cooling to 500oC and then furnace cooling. A JEOL JEM-2000FC TEM was used for carbides morphology observation by BF-TEM and phase identification by selected area diffraction patterns (SADPs). A JEOL, ARM200F TEM equipped with a Gatan Quantum ERS electron energy loss spectrometer was used for EELS and EDS. Both microscopes were operated at the accelerating voltage of 200 kV.
結果と考察 / Results and Discussion
BF-TEM images in Figs. 1 show that the microstructure after annealing of the reference (R), Mo1 and W1 irons consists of eutectic carbides with faulting contrast and secondary carbides. Coarser secondary carbides were found in areas close to eutectic carbides, whereas finer secondary carbides were found away from eutectic carbides to the centre of the prior dendrites. The Mo1 alloy contains finer and denser secondary carbides when compared to secondary carbides in R and W1 irons. Inset selected area diffraction patterns (SADPs) in Fig. 1 confirm that, after annealing, the eutectic carbides and secondary carbides are M7C3 and M23C6, and that the matrix is ferrite (α). The coarse secondary carbides may be formed on the preferred directions in the first step. Then, the fine secondary carbide precipitation may be occurred during longer holding time or during slow cooling. TEM-EDS in Fig. 2(a) revealed that the Fe/Cr wt.% ratio of eutectic M7C3 carbides is approximately 0.4, while that of coarse and fine secondary M23C6 carbides in both alloys are in range of 0.52-0.69. Preliminary EELS results are given in Fig. 2(b). The difference in the characteristic C K-edge of M7C3 and M23C6 in all irons includes: (i) the peak at 289 eV (marked by arrows in Fig. 2(b)) has been observed only in the case of M7C3 and (ii) the ratio of peak height between peak 1 at 286 eV and peak 2 at 294 eV is higher for the case of M7C3.
図・表・数式 / Figures, Tables and Equations
Fig. 1. BF-TEM images and corresponding SADPs from eutectic M7C3 carbides, coarse and fine secondary M23C6 carbides, and the ferrite (a) matrix: (a) R, (b) Mo1 and (c) W1 irons.
Fig. 2. (a) TEM-EDS spectra of eutectic M7C3 and coarse M23C6 in the R iron, (b) Comparision of the C K-edge EELS spectra from eutectic M7C3 and coarse M23C6 in the R, Mo1 and W1 irons.
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
This research was supported by the Collaborative Research Program of Institute for Chemical Research, Kyoto University and the financial funding supports from Thailand Graduate Institute of Science and Technology: TGIST (TG-MT-NU-62-020D), National Science and Technology Development Agency (NSTDA) and Department of Physics, Faculty of Science, Naresuan University.
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)
-
Kittikhun Ruangchai, Electron microscopy of carbides in annealed 28 wt% Cr - 1 wt% (Mo/W) cast irons, Materials Characterization, 198, 112723(2023).
DOI: 10.1016/j.matchar.2023.112723
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