Deeply revealing the coupled formation mechanism of inclusions and precipitates in 654NMo ingot

This study systematically investigates the formation, evolution, and distribution of inclusions in a 654NMo ingot during solidification by combining lattice mismatch degree with multi-scale characterization, and elucidates the coupled precipitation mechanisms of inclusions and precipitates. The domi...

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Main Authors: Hongchun Zhu, Xinbo Yan, Huabing Li, Zhiyu He, Zhuowen Ni, Hao Feng, Shucai Zhang, Zhouhua Jiang, Pengchong Lu
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S2238785425016904
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author Hongchun Zhu
Xinbo Yan
Huabing Li
Zhiyu He
Zhuowen Ni
Hao Feng
Shucai Zhang
Zhouhua Jiang
Pengchong Lu
author_facet Hongchun Zhu
Xinbo Yan
Huabing Li
Zhiyu He
Zhuowen Ni
Hao Feng
Shucai Zhang
Zhouhua Jiang
Pengchong Lu
author_sort Hongchun Zhu
collection DOAJ
description This study systematically investigates the formation, evolution, and distribution of inclusions in a 654NMo ingot during solidification by combining lattice mismatch degree with multi-scale characterization, and elucidates the coupled precipitation mechanisms of inclusions and precipitates. The dominant inclusions in the ingot are Al2O3–MnS–CrN composite inclusions. Initially, MnS nucleates on Al2O3 inclusions, followed by the heterogeneous nucleation of CrN on the Al2O3–MnS interface, ultimately forming Al2O3–MnS–CrN composite inclusions. The inclusion number density is significantly higher at the ingot edge compared to the center, while the bottom zone exhibits a greater density than the top and middle. This distribution pattern is attributed to the higher solidification rates at the edge and bottom. Conversely, the center zone contains a larger proportion of large-sized inclusions, resulting from slower solidification, which promotes inclusion collision and coalescence. Furthermore, the Mo3Si phase precipitates around the Al2O3–MnS–CrN composite inclusions. This phenomenon occurs because CrN nucleation on the Al2O3–MnS composite inclusions decreases the Cr and N of the surrounding matrix, creating a solute-depleted zone that facilitates Mo3Si precipitation. These findings provide a scientific basis for alloy design and solidification process optimization of high-nitrogen stainless steels.
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institution Kabale University
issn 2238-7854
language English
publishDate 2025-07-01
publisher Elsevier
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series Journal of Materials Research and Technology
spelling doaj-art-4e7a8bbc3440479eb02c95725d875d8b2025-08-20T03:28:14ZengElsevierJournal of Materials Research and Technology2238-78542025-07-01373388339610.1016/j.jmrt.2025.07.032Deeply revealing the coupled formation mechanism of inclusions and precipitates in 654NMo ingotHongchun Zhu0Xinbo Yan1Huabing Li2Zhiyu He3Zhuowen Ni4Hao Feng5Shucai Zhang6Zhouhua Jiang7Pengchong Lu8School of Metallurgy, Northeastern University, Shenyang, 110819, ChinaSchool of Metallurgy, Northeastern University, Shenyang, 110819, ChinaSchool of Metallurgy, Northeastern University, Shenyang, 110819, China; Key Laboratory for Ecological Metallurgy of Multimetallic Ores (Ministry of Education), Northeastern University, Shenyang, 110819, China; Corresponding author. School of Metallurgy, Northeastern University, Shenyang, 110819, China.School of Metallurgy, Northeastern University, Shenyang, 110819, China; Corresponding author.School of Metallurgy, Northeastern University, Shenyang, 110819, ChinaSchool of Metallurgy, Northeastern University, Shenyang, 110819, ChinaSchool of Metallurgy, Northeastern University, Shenyang, 110819, ChinaSchool of Metallurgy, Northeastern University, Shenyang, 110819, China; Key Laboratory for Ecological Metallurgy of Multimetallic Ores (Ministry of Education), Northeastern University, Shenyang, 110819, ChinaSchool of Metallurgy, Northeastern University, Shenyang, 110819, ChinaThis study systematically investigates the formation, evolution, and distribution of inclusions in a 654NMo ingot during solidification by combining lattice mismatch degree with multi-scale characterization, and elucidates the coupled precipitation mechanisms of inclusions and precipitates. The dominant inclusions in the ingot are Al2O3–MnS–CrN composite inclusions. Initially, MnS nucleates on Al2O3 inclusions, followed by the heterogeneous nucleation of CrN on the Al2O3–MnS interface, ultimately forming Al2O3–MnS–CrN composite inclusions. The inclusion number density is significantly higher at the ingot edge compared to the center, while the bottom zone exhibits a greater density than the top and middle. This distribution pattern is attributed to the higher solidification rates at the edge and bottom. Conversely, the center zone contains a larger proportion of large-sized inclusions, resulting from slower solidification, which promotes inclusion collision and coalescence. Furthermore, the Mo3Si phase precipitates around the Al2O3–MnS–CrN composite inclusions. This phenomenon occurs because CrN nucleation on the Al2O3–MnS composite inclusions decreases the Cr and N of the surrounding matrix, creating a solute-depleted zone that facilitates Mo3Si precipitation. These findings provide a scientific basis for alloy design and solidification process optimization of high-nitrogen stainless steels.http://www.sciencedirect.com/science/article/pii/S2238785425016904654NMo ingotSolidificationInclusionPrecipitation phase
spellingShingle Hongchun Zhu
Xinbo Yan
Huabing Li
Zhiyu He
Zhuowen Ni
Hao Feng
Shucai Zhang
Zhouhua Jiang
Pengchong Lu
Deeply revealing the coupled formation mechanism of inclusions and precipitates in 654NMo ingot
Journal of Materials Research and Technology
654NMo ingot
Solidification
Inclusion
Precipitation phase
title Deeply revealing the coupled formation mechanism of inclusions and precipitates in 654NMo ingot
title_full Deeply revealing the coupled formation mechanism of inclusions and precipitates in 654NMo ingot
title_fullStr Deeply revealing the coupled formation mechanism of inclusions and precipitates in 654NMo ingot
title_full_unstemmed Deeply revealing the coupled formation mechanism of inclusions and precipitates in 654NMo ingot
title_short Deeply revealing the coupled formation mechanism of inclusions and precipitates in 654NMo ingot
title_sort deeply revealing the coupled formation mechanism of inclusions and precipitates in 654nmo ingot
topic 654NMo ingot
Solidification
Inclusion
Precipitation phase
url http://www.sciencedirect.com/science/article/pii/S2238785425016904
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