Effect of Niobium on the Formation of Microstructure and Grain Boundary in Fe-Nb and Fe-C-Nb Alloys
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- Kudoh Masayuki
- Professor Emeritus, Hokkaido University
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- Tezuka Masataka
- Graduate Student, Hokkaido University
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- Matsuura Kiyotaka
- Division of Materials Science and Engineering, Hokkaido University
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Abstract
The changes in degree of undercooling, secondary dendrite arm spacing and microstructure were investigated by using three cooling methods. The Fe–Nb binary alloys and Fe–0.1mass%C–Nb ternary alloys having various niobium concentrations ranging from 0.50 to 6 mass% were used. The Fe–C–Nb ternary alloys were used to investigate the role of niobiumcarbide (NbC) as the heterogeneous nucleation site. The degree of undercooling in both alloys changed with niobium concentration and that in the ternary alloy was always smaller than that in the binary alloys because of the presence of NbC. Dendritic microstructures were observed in both alloys quenched from 1 673 K after cooling at a rate of 0.028 K/s when Nb concentration exceeds 2 mass%. An Fe–0.1mass%C–3.0mass%Nb alloy air-cooled from 1 473 K also exhibited the dendritic microstructure, while an Fe–3.0%Nb alloy similarly air-cooled did not exhibit the dendritic microstructure. Then, grain boundary in the Fe–0.1mass%C–3.0mass%Nb alloy was formed between the arrays of dendrites, while it wasn't formed between secondary dendrite arms. Furthermore, the microstructure in an Fe–0.10%C–1.0%Nb alloy which was air-cooled from liquid state exhibited fine dendrite microstructure.
Journal
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- ISIJ International
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ISIJ International 46 (12), 1871-1876, 2006
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
- 1390001206487496448
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- NII Article ID
- 10018554964
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- NII Book ID
- AA10680712
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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