Isothermal Transformation in Fe–N Hypereutectoid Alloy
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- Nakada Nobuo
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University
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- Fukuzawa Norihide
- Graduate Student of Engineering, Kyushu University
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- Tsuchiyama Toshihiro
- International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University
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- Takaki Setsuo
- Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University
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- Koyano Tamotsu
- Cryogenics Division, Research Facility Center, University of Tsukuba
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- Iwamoto Takashi
- Steel Research Laboratory, JFE Steel Corporation
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- Omori Yasuhiro
- Steel Research Laboratory, JFE Steel Corporation
Bibliographic Information
- Other Title
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- Isothermal Transformation in Fe^|^ndash;N Hypereutectoid Alloy
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Abstract
In order to understand the mechanism of isothermal transformation of Fe–N alloy, the isothermal transformation microstructure that forms in a wide temperature range below Ae1 was investigated in Fe–2.6 mass%N hypereutectoid alloy by means of the electron back scatter diffraction method in addition to the conventional microstructural observation methods. High-nitrogen austenite fully decomposed to ferrite and Fe4N over the entire temperature range, and the time-temperature-transformation (TTT) diagram had a C shape with a nose temperature around 700 K. The hardness linearly increased with decreasing transformation temperature because the microstructure became finer, but the morphology of the (ferrite + Fe4N) structure changed discontinuously at around 800 K. From the microstructural and crystallographic analyses, it was concluded that the microstructure formed at higher temperature is a lamellar eutectoid structure, braunite, while the other is an upper bainitic structure containing bainitic ferrite formed through a displacive mechanism and Fe4N formed by concentration and ordering of the nitrogen. Since Fe4N is a counterpart of the cementite in Fe–C alloy, the respective structures are similar to pearlite and upper bainite in carbon steel.
Journal
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- ISIJ International
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ISIJ International 53 (1), 139-144, 2013
The Iron and Steel Institute of Japan
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Details 詳細情報について
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- CRID
- 1390282681464840960
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- NII Article ID
- 10031170298
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- NII Book ID
- AA10680712
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- COI
- 1:CAS:528:DC%2BC3sXhsFSisbk%3D
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- ISSN
- 13475460
- 09151559
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- Text Lang
- en
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- Data Source
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- JaLC
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed