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Henkelmann G, Waldow D, Liu M, Lührs L, Li Y, Weissmüller J. Self-Detachment and Subsurface Densification of Dealloyed Nanoporous Thin Films. NANO LETTERS 2022; 22:6787-6793. [PMID: 35952308 PMCID: PMC9413411 DOI: 10.1021/acs.nanolett.2c02666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/05/2022] [Indexed: 05/10/2023]
Abstract
Experiment shows thin films of dealloyed nanoporous gold (NPG) spontaneously detaching from massive gold base layers. NPG can also densify near its external surface. This is naturally reproduced by kinetic Monte Carlo (KMC) simulation of dealloying and coarsening and so appears generic for nanoscale network materials evolving by surface diffusion. Near the porous layer's external surface and near its interface with the base layer, gradients in the depth-profile of a laterally averaged mean surface curvature provide driving forces for diffusion and cause divergences of the net fluxes of matter, leading to accretion/densification or to erosion/disconnection. As a toy model, the morphology evolution of substrate-supported nanopillars by surface diffusion illustrates and confirms our considerations. Contrary to cylindrical nanowires, the ligaments in nanoporous materials exhibit pre-existing gradients in the mean curvature. The Plateau-Rayleigh long-wavelength stability criterion is then not applicable and the disconnection accelerated.
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Affiliation(s)
- Gideon Henkelmann
- Institute
of Materials Physics and Technology, Hamburg
University of Technology, 21073 Hamburg, Germany
| | - Diana Waldow
- Institute
of Materials Physics and Technology, Hamburg
University of Technology, 21073 Hamburg, Germany
| | - Maowen Liu
- Institute
of Materials Physics and Technology, Hamburg
University of Technology, 21073 Hamburg, Germany
- Institute
of Materials Mechanics, Helmholtz-Zentrum
Hereon, 21502 Geesthacht, Germany
| | - Lukas Lührs
- Institute
of Materials Physics and Technology, Hamburg
University of Technology, 21073 Hamburg, Germany
| | - Yong Li
- Institute
of Materials Physics and Technology, Hamburg
University of Technology, 21073 Hamburg, Germany
- Institute
of Materials Mechanics, Helmholtz-Zentrum
Hereon, 21502 Geesthacht, Germany
| | - Jörg Weissmüller
- Institute
of Materials Physics and Technology, Hamburg
University of Technology, 21073 Hamburg, Germany
- Institute
of Materials Mechanics, Helmholtz-Zentrum
Hereon, 21502 Geesthacht, Germany
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Yasuda H, Morishita K, Nakatsuka N, Nishimura T, Yoshiya M, Sugiyama A, Uesugi K, Takeuchi A. Dendrite fragmentation induced by massive-like δ-γ transformation in Fe-C alloys. Nat Commun 2019; 10:3183. [PMID: 31320622 PMCID: PMC6639379 DOI: 10.1038/s41467-019-11079-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 06/21/2019] [Indexed: 11/09/2022] Open
Abstract
Dendrite arm fragmentation is considered in solidification structure tailoring. Time-resolved and in situ imaging using synchrotron radiation X-rays allows the observation of dendrite arm fragmentation in Fe-C alloys. Here we report a dendrite arm fragmentation mechanism. A massive-like transformation from ferrite to austenite rather than the peritectic reaction occurs during or after ferrite solidification. The transformation produces refined austenite grains and ferrite-austenite boundaries in dendrite arms. The austenite grains are fragmented by the liquid phase that is produced at the grain boundary. In unidirectional solidification, a slight increase in temperature moves the ferrite-austenite interface backwards and promotes detachment of the primary and secondary arms at the δ-γ interface via a reverse peritectic reaction. The results show a massive-like transformation inducing the dendrite arm fragmentation has a role in formation of the solidification structure and the austenite grain structures in the Fe-C alloys.
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Affiliation(s)
- Hideyuki Yasuda
- Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto, 606-8501, Japan.
| | - Kohei Morishita
- Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto, 606-8501, Japan.,Department of Materials Science and Engineering, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Noriaki Nakatsuka
- Department of Adaptive Machine Systems, Osaka University, Suita, Osaka, 565-0871, Japan.,Melting Section, Manufacturing Department, Moka Plant, Aluminum and Copper Business, Kobe Steel Ltd, 15 Kinugaoka, Moka, Tochigi, 321-4367, Japan
| | - Tomohiro Nishimura
- Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto, 606-8501, Japan.,Kobe Corporate Research Laboratories, Kobe Steel Ltd., 1-5-5 Takatsukadai, Nishiku, Kobe, Hyogo, 651-2271, Japan
| | - Masato Yoshiya
- Department of Adaptive Machine Systems, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Akira Sugiyama
- Department of Mechanical Engineering for Transportation, Osaka Sangyo University, Daito, Osaka, 574-8530, Japan
| | - Kentaro Uesugi
- Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Sayo-cho, Hyogo, 679-5198, Japan
| | - Akihisa Takeuchi
- Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Sayo-cho, Hyogo, 679-5198, Japan
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Dedovets D, Monteux C, Deville S. Five-dimensional imaging of freezing emulsions with solute effects. Science 2018; 360:303-306. [DOI: 10.1126/science.aar4503] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 02/26/2018] [Indexed: 12/27/2022]
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Cool T, Voorhees PW. Dendrite fragmentation: an experiment-driven simulation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:rsta.2017.0213. [PMID: 29311211 PMCID: PMC5784103 DOI: 10.1098/rsta.2017.0213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/17/2017] [Indexed: 05/25/2023]
Abstract
The processes leading to the fragmentation of secondary dendrite arms are studied using a three-dimensional Sn dendritic structure that was measured experimentally as an initial condition in a phase-field simulation. The phase-field model replicates the kinetics of the coarsening process seen experimentally. Consistent with the experiment, the simulations of the Sn-rich dendrite show that secondary dendrite arm coalescence is prevalent and that fragmentation is not. The lack of fragmentation is due to the non-axisymmetric morphology and comparatively small spacing of the dendrite arms. A model for the coalescence process is proposed, and, consistent with the model, the radius of the contact region following coalescence increases as t1/3 We find that small changes in the width and spacing of the dendrite arms can lead to a very different fragmentation-dominated coarsening process. Thus, the alloy system and growth conditions of the dendrite can have a major impact on the fragmentation process.This article is part of the theme issue 'From atomistic interfaces to dendritic patterns'.
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Affiliation(s)
- T Cool
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - P W Voorhees
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
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Zhang Q, Fang H, Xue H, Pan S, Rettenmayr M, Zhu M. Interaction of local solidification and remelting during dendrite coarsening - modeling and comparison with experiments. Sci Rep 2017; 7:17809. [PMID: 29259208 PMCID: PMC5736763 DOI: 10.1038/s41598-017-17857-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/29/2017] [Indexed: 11/22/2022] Open
Abstract
The microstructural evolution of dendrite coarsening during isothermal holding is simulated using a quantitative cellular automaton (CA) model involving the mechanisms of both solidification and melting. The present model encompasses the essential aspects of thermodynamics and kinetics, particularly the evolution/influence of composition, temperature, and curvature, leading to valid simulations of simultaneous solidification and melting. Model validation is performed through a comparison of the CA simulations with analytical predictions for a liquid pool migrating in the mushy zone of a SCN–0.3 wt.% ACE alloy due to temperature gradient zone melting. The model is applied to simulate the microstructural evolution of columnar dendrites of a SCN–2.0 wt.% ACE alloy during isothermal holding in a mushy zone. The simulation results are compared with those of a previous CA model that does not include the melting mechanism under otherwise identical conditions. The role of melting for dendrite coarsening is quantified, showing how the melting influences the coarsening process. The present model effectively reproduces the typical dendrite coarsening features as observed in experiments reported in the literature. The simulations reveal how local solidification and melting stimulate each other through the complicated interactions between phase transformation, interface shape variation, and solute diffusion.
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Affiliation(s)
- Qingyu Zhang
- Jiangsu Key Laboratory for Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing, 211189, China
| | - Hui Fang
- Jiangsu Key Laboratory for Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing, 211189, China
| | - Hua Xue
- Jiangsu Key Laboratory for Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing, 211189, China
| | - Shiyan Pan
- School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Markus Rettenmayr
- Otto Schott Institute of Materials Research, Friedrich Schiller University, Löbdergraben 32, Jena, 07743, Germany
| | - Mingfang Zhu
- Jiangsu Key Laboratory for Advanced Metallic Materials, School of Materials Science and Engineering, Southeast University, Nanjing, 211189, China.
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