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In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials
The phase transformation in two modes, including both displacive and massive growth of τ-phase from ε-MnAl(C), was observed by in situ transmission electron microscopy. The exact temperature range for different phase transformation modes was determined by magnetic measurements. The displacive growth...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5615671/ https://www.ncbi.nlm.nih.gov/pubmed/28858231 http://dx.doi.org/10.3390/ma10091016 |
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author | Si, Ping-Zhan Qian, Hui-Dong Choi, Chul-Jin Park, Jihoon Han, Sangho Ge, Hong-Liang Shinde, Kiran P. |
author_facet | Si, Ping-Zhan Qian, Hui-Dong Choi, Chul-Jin Park, Jihoon Han, Sangho Ge, Hong-Liang Shinde, Kiran P. |
author_sort | Si, Ping-Zhan |
collection | PubMed |
description | The phase transformation in two modes, including both displacive and massive growth of τ-phase from ε-MnAl(C), was observed by in situ transmission electron microscopy. The exact temperature range for different phase transformation modes was determined by magnetic measurements. The displacive growth of ε→τ in Mn(54)Al(46) (or Mn(54)Al(46)C(2.44)) occurs at temperatures below 650 K (or 766 K), above which both modes coexist. One-third or less of the ε-phase can be transformed into τ-phase via displacive mode while the remaining two-thirds or more via massive mode. In bulk τ-phase, most τ-nanocrystals formed via displacive mode are distributed in the matrix of large τ-grains that formed via massive mode. The typical massive growth rate of the τ-phase is 8–60 nm/s, while the displacive growth rate is low. A more complete understanding of the ε→τ phase transformations in the MnAl-based magnets was provided in this work, based on which the annealing process for ε→τ was optimized and thus high purity τ-phase with high saturation magnetization was obtained. |
format | Online Article Text |
id | pubmed-5615671 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-56156712017-09-28 In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials Si, Ping-Zhan Qian, Hui-Dong Choi, Chul-Jin Park, Jihoon Han, Sangho Ge, Hong-Liang Shinde, Kiran P. Materials (Basel) Article The phase transformation in two modes, including both displacive and massive growth of τ-phase from ε-MnAl(C), was observed by in situ transmission electron microscopy. The exact temperature range for different phase transformation modes was determined by magnetic measurements. The displacive growth of ε→τ in Mn(54)Al(46) (or Mn(54)Al(46)C(2.44)) occurs at temperatures below 650 K (or 766 K), above which both modes coexist. One-third or less of the ε-phase can be transformed into τ-phase via displacive mode while the remaining two-thirds or more via massive mode. In bulk τ-phase, most τ-nanocrystals formed via displacive mode are distributed in the matrix of large τ-grains that formed via massive mode. The typical massive growth rate of the τ-phase is 8–60 nm/s, while the displacive growth rate is low. A more complete understanding of the ε→τ phase transformations in the MnAl-based magnets was provided in this work, based on which the annealing process for ε→τ was optimized and thus high purity τ-phase with high saturation magnetization was obtained. MDPI 2017-08-31 /pmc/articles/PMC5615671/ /pubmed/28858231 http://dx.doi.org/10.3390/ma10091016 Text en © 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Si, Ping-Zhan Qian, Hui-Dong Choi, Chul-Jin Park, Jihoon Han, Sangho Ge, Hong-Liang Shinde, Kiran P. In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials |
title | In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials |
title_full | In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials |
title_fullStr | In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials |
title_full_unstemmed | In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials |
title_short | In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials |
title_sort | in situ observation of phase transformation in mnal(c) magnetic materials |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5615671/ https://www.ncbi.nlm.nih.gov/pubmed/28858231 http://dx.doi.org/10.3390/ma10091016 |
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