An Overview on Atomistic Mechanisms of Heterogeneous Nucleation
Our current understanding of heterogeneous nucleation has been dominated by the classical nucleation theory (CNT) with little progress of significance being made in past 100 years. In recent years under the financial support from EPSRC for the LiME Research Hub, we have made substantial progress on...
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MDPI AG
2022-09-01
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| Online Access: | https://www.mdpi.com/2075-4701/12/9/1547 |
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| author | Zhongyun Fan Hua Men |
| author_facet | Zhongyun Fan Hua Men |
| author_sort | Zhongyun Fan |
| collection | DOAJ |
| description | Our current understanding of heterogeneous nucleation has been dominated by the classical nucleation theory (CNT) with little progress of significance being made in past 100 years. In recent years under the financial support from EPSRC for the LiME Research Hub, we have made substantial progress on understanding heterogeneous nucleation at atomic level using a combination of molecular dynamics simulations and advanced high-resolution electron microscopy. We found that heterogeneous nucleation proceeds through a three-layer nucleation mechanism to produce a 2D nucleus. The atomistic mechanisms responsible for accommodating lattice misfit are dependent on misfit (<i>f</i>): (1) for systems with small negative misfit (−12.5% < <i>f</i> < 0), misfit is accommodated by dislocation mechanism; (2) for systems with small positive misfit (0 < <i>f</i> < 12.5%), misfit is accommodated by vacancy mechanism; and (3) for systems with large misfit (|<i>f</i>| > 12.5%), misfit is accommodated in two steps: formation of coincidence site lattice during prenucleation to accommodate the major misfit (<i>f</i><sub>csL</sub>) and the residual misfit (<i>f</i><sub>r</sub>) is accommodated during heterogeneous nucleation by the dislocation mechanism if the residual misfit is less than 0 or by the vacancy mechanism if the residual misfit is larger than 0. Further analysis suggests that heterogeneous nucleation is spontaneous thus barrierless and deterministic rather than stochastic. |
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| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-09T23:08:41Z |
| publishDate | 2022-09-01 |
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| spelling | doaj.art-3d6cb630236a4d55a31b7a497f9f39f92023-11-23T17:47:55ZengMDPI AGMetals2075-47012022-09-01129154710.3390/met12091547An Overview on Atomistic Mechanisms of Heterogeneous NucleationZhongyun Fan0Hua Men1Brunel Centre for Advanced Solidification Technology (BCAST), Brunel University London, Uxbridge UB8 3PH, UKBrunel Centre for Advanced Solidification Technology (BCAST), Brunel University London, Uxbridge UB8 3PH, UKOur current understanding of heterogeneous nucleation has been dominated by the classical nucleation theory (CNT) with little progress of significance being made in past 100 years. In recent years under the financial support from EPSRC for the LiME Research Hub, we have made substantial progress on understanding heterogeneous nucleation at atomic level using a combination of molecular dynamics simulations and advanced high-resolution electron microscopy. We found that heterogeneous nucleation proceeds through a three-layer nucleation mechanism to produce a 2D nucleus. The atomistic mechanisms responsible for accommodating lattice misfit are dependent on misfit (<i>f</i>): (1) for systems with small negative misfit (−12.5% < <i>f</i> < 0), misfit is accommodated by dislocation mechanism; (2) for systems with small positive misfit (0 < <i>f</i> < 12.5%), misfit is accommodated by vacancy mechanism; and (3) for systems with large misfit (|<i>f</i>| > 12.5%), misfit is accommodated in two steps: formation of coincidence site lattice during prenucleation to accommodate the major misfit (<i>f</i><sub>csL</sub>) and the residual misfit (<i>f</i><sub>r</sub>) is accommodated during heterogeneous nucleation by the dislocation mechanism if the residual misfit is less than 0 or by the vacancy mechanism if the residual misfit is larger than 0. Further analysis suggests that heterogeneous nucleation is spontaneous thus barrierless and deterministic rather than stochastic.https://www.mdpi.com/2075-4701/12/9/1547heterogeneous nucleationmolecular dynamics simulationlattice misfitsolidification |
| spellingShingle | Zhongyun Fan Hua Men An Overview on Atomistic Mechanisms of Heterogeneous Nucleation Metals heterogeneous nucleation molecular dynamics simulation lattice misfit solidification |
| title | An Overview on Atomistic Mechanisms of Heterogeneous Nucleation |
| title_full | An Overview on Atomistic Mechanisms of Heterogeneous Nucleation |
| title_fullStr | An Overview on Atomistic Mechanisms of Heterogeneous Nucleation |
| title_full_unstemmed | An Overview on Atomistic Mechanisms of Heterogeneous Nucleation |
| title_short | An Overview on Atomistic Mechanisms of Heterogeneous Nucleation |
| title_sort | overview on atomistic mechanisms of heterogeneous nucleation |
| topic | heterogeneous nucleation molecular dynamics simulation lattice misfit solidification |
| url | https://www.mdpi.com/2075-4701/12/9/1547 |
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