| Autor: |
Tsumuraya, Takao, Watanabe, Ikumu, Sawaguchi, Takahiro |
| Rok vydání: |
2020 |
| Předmět: |
|
| Zdroj: |
Phys. Rev. Research 3, 033215 (2021) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1103/PhysRevResearch.3.033215 |
| Popis: |
A class of Fe-Mn-Si-based alloys exhibits a reversible martensitic transformation between the $\gamma$ phase with a face-centered cubic~(fcc) structure and an $\epsilon$ phase with a hexagonal close-packed (hcp) structure. During the deformation-induced $\gamma$--$\epsilon$ transformation, we identified a phase that is different from the $\epsilon$ phase. In this new phase, the electron diffraction spots are located at the 1/3 positions that correspond to the $\{$0002$\}$ plane of the $\epsilon$ (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 $\gamma$ and $\epsilon$ 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 close to the $\epsilon$ 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. |
| Databáze: |
arXiv |
| Externí odkaz: |
|
