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Effect of Transport Mechanism on the Coarsening of Bicontinuous Structures: A Comparison between Bulk and Surface Diffusion
- Publication Year :
- 2020
-
Abstract
- Coarsening of bicontinuous microstructures is observed in a variety of systems, such as nanoporous metals and mixtures that have undergone spinodal decomposition. To better understand the morphological evolution of these structures during coarsening, we compare the morphologies resulting from two different coarsening mechanisms, surface and bulk diffusion. We perform phase-field simulations of coarsening via each mechanism in a two-phase mixture at nominal volume fractions of 50%-50% and 36%-64%, and the simulated structures are characterized in terms of topology (genus density), the interfacial shape distribution, structure factor, and autocorrelations of phase and mean curvature. We observe self-similar evolution of morphology and topology and agreement with the expected power laws for dynamic scaling, in which the characteristic length scale increases over time proportionally to $t^{1/4}$ for surface diffusion and $t^{1/3}$ for bulk diffusion. While we observe the expected difference in the coarsening kinetics, we find that differences in self-similar morphology due to coarsening mechanism are relatively small, although typically they are larger at 36% volume fraction than at 50% volume fraction. In particular, we find that bicontinuous structures coarsened via surface diffusion have lower scaled genus densities than structures coarsened via bulk diffusion. We also compare the self-similar morphologies to those in literature and to two model bicontinuous structures, namely, constant-mean-curvature surfaces based on the Schoen G minimal surface and random leveled-wave structures. The average scaled mean curvatures of these model structures agree reasonably with those of the coarsened structures at both 36% and 50%, but we find substantial disagreements in the scaled genus densities and the standard deviations of mean curvature.<br />Main text: 20 pages, 7 figures. Supplemental Material: 9 pages, 6 figures
- Subjects :
- Surface diffusion
Condensed Matter - Materials Science
Minimal surface
Materials science
Mean curvature
Physics and Astronomy (miscellaneous)
Characteristic length
Spinodal decomposition
Materials Science (cond-mat.mtrl-sci)
FOS: Physical sciences
Thermodynamics
02 engineering and technology
Condensed Matter - Soft Condensed Matter
021001 nanoscience & nanotechnology
01 natural sciences
Power law
Condensed Matter::Soft Condensed Matter
0103 physical sciences
Volume fraction
Soft Condensed Matter (cond-mat.soft)
General Materials Science
Diffusion (business)
010306 general physics
0210 nano-technology
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....799e106c501ae655caaf9b8b413e9b63