Shear Deformation Helps Phase Transition in Pure Iron Thin Films with 'Inactive' Surfaces: A Molecular Dynamics Study
| Autor: | Binjun Wang, Yunqiang Jiang, Ting Ruan, Chun Xu |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Phase transition
Work (thermodynamics) Materials science thin film General Chemical Engineering Nucleation Stacking 02 engineering and technology 01 natural sciences solid-solid phase transition Inorganic Chemistry Molecular dynamics iron 0103 physical sciences lcsh:QD901-999 General Materials Science shear deformation Thin film 010302 applied physics Deformation (mechanics) 021001 nanoscience & nanotechnology Condensed Matter Physics molecular dynamics simulation Chemical physics Free surface lcsh:Crystallography 0210 nano-technology |
| Zdroj: | Crystals Volume 10 Issue 10 Crystals, Vol 10, Iss 855, p 855 (2020) |
| ISSN: | 2073-4352 |
| DOI: | 10.3390/cryst10100855 |
| Popis: | In a previous study, it was shown that the (111)fcc, (110)fcc and (111)bcc free surfaces do not assist the phase transitions as nucleation sites upon heating/cooling in iron (Fe) thin slabs. In the present work, the three surfaces are denoted as &ldquo inactive&rdquo free surfaces. The phase transitions in Fe thin films with these &ldquo free surfaces have been studied using a classical molecular dynamics simulation and the Meyer&ndash Entel potential. Our results show that shear deformation helps to activate the free surface as nucleation sites. The transition mechanisms are different in dependence on the surface orientation. In film with the (111)fcc free surface, two body-centered cubic (bcc) phases with different crystalline orientations nucleate at the free surface. In film with the (110)fcc surface, the nucleation sites are the intersections between the surfaces and stacking faults. In film with the (111)bcc surface, both heterogeneous nucleation at the free surface and homogeneous nucleation in the bulk material are observed. In addition, the transition pathways are analyzed. In all cases studied, the unstrained system is stable and no phase transition takes place. This work may be helpful to understand the mechanism of phase transition in nanoscale systems under external deformation. |
| Databáze: | OpenAIRE |
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