Origin of phase stability in Fe with long-period stacking order as an intermediate phase in cyclic γ-ε martensitic transformation
A class of Fe-Mn-Si–based alloys exhibit a reversible martensitic transformation between the γ phase with a face-centered cubic (fcc) structure and an ε phase with a hexagonal close-packed (hcp) structure. During the deformation-induced γ-ε transformation, we identified a phase that is different fro...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2021-09-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.3.033215 |
| _version_ | 1797210950733922304 |
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| author | Takao Tsumuraya Ikumu Watanabe Takahiro Sawaguchi |
| author_facet | Takao Tsumuraya Ikumu Watanabe Takahiro Sawaguchi |
| author_sort | Takao Tsumuraya |
| collection | DOAJ |
| description | A class of Fe-Mn-Si–based alloys exhibit a reversible martensitic transformation between the γ phase with a face-centered cubic (fcc) structure and an ε phase with a hexagonal close-packed (hcp) structure. During the deformation-induced γ-ε transformation, we identified a phase that is different from the ε phase. In this phase, the electron diffraction spots are located at the 1/3 positions that correspond to the {0002} plane of the ε (hcp) phase with 2H structure, which suggests long-period stacking order (LPSO). To understand the stacking pattern and explore the possible existence of an LPSO phase as an intermediate between the γ and ε phases, the phase stability of various structural polytypes of iron was examined using first-principles calculations with a spin-polarized form of the generalized gradient approximation in density functional theory. We found that an antiferromagnetic ordered 6H_{2} structure is the most stable among the candidate LPSO structures and is energetically closest to the ε phase, which suggests that the observed LPSO-like phase adopts the 6H_{2} structure. Furthermore, we determined that the phase stability can be attributed to the valley depth in the density of states, close to the Fermi level. |
| first_indexed | 2024-04-24T10:18:44Z |
| format | Article |
| id | doaj.art-bed2828031874b85888a09c3dbc21f4e |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:18:44Z |
| publishDate | 2021-09-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-bed2828031874b85888a09c3dbc21f4e2024-04-12T17:13:35ZengAmerican Physical SocietyPhysical Review Research2643-15642021-09-013303321510.1103/PhysRevResearch.3.033215Origin of phase stability in Fe with long-period stacking order as an intermediate phase in cyclic γ-ε martensitic transformationTakao TsumurayaIkumu WatanabeTakahiro SawaguchiA class of Fe-Mn-Si–based alloys exhibit a reversible martensitic transformation between the γ phase with a face-centered cubic (fcc) structure and an ε phase with a hexagonal close-packed (hcp) structure. During the deformation-induced γ-ε transformation, we identified a phase that is different from the ε phase. In this phase, the electron diffraction spots are located at the 1/3 positions that correspond to the {0002} plane of the ε (hcp) phase with 2H structure, which suggests long-period stacking order (LPSO). To understand the stacking pattern and explore the possible existence of an LPSO phase as an intermediate between the γ and ε phases, the phase stability of various structural polytypes of iron was examined using first-principles calculations with a spin-polarized form of the generalized gradient approximation in density functional theory. We found that an antiferromagnetic ordered 6H_{2} structure is the most stable among the candidate LPSO structures and is energetically closest to the ε phase, which suggests that the observed LPSO-like phase adopts the 6H_{2} structure. Furthermore, we determined that the phase stability can be attributed to the valley depth in the density of states, close to the Fermi level.http://doi.org/10.1103/PhysRevResearch.3.033215 |
| spellingShingle | Takao Tsumuraya Ikumu Watanabe Takahiro Sawaguchi Origin of phase stability in Fe with long-period stacking order as an intermediate phase in cyclic γ-ε martensitic transformation Physical Review Research |
| title | Origin of phase stability in Fe with long-period stacking order as an intermediate phase in cyclic γ-ε martensitic transformation |
| title_full | Origin of phase stability in Fe with long-period stacking order as an intermediate phase in cyclic γ-ε martensitic transformation |
| title_fullStr | Origin of phase stability in Fe with long-period stacking order as an intermediate phase in cyclic γ-ε martensitic transformation |
| title_full_unstemmed | Origin of phase stability in Fe with long-period stacking order as an intermediate phase in cyclic γ-ε martensitic transformation |
| title_short | Origin of phase stability in Fe with long-period stacking order as an intermediate phase in cyclic γ-ε martensitic transformation |
| title_sort | origin of phase stability in fe with long period stacking order as an intermediate phase in cyclic γ ε martensitic transformation |
| url | http://doi.org/10.1103/PhysRevResearch.3.033215 |
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