Ordered Liquid Aluminum at the Interface with Sapphire

Oh, Sang Ho; Kauffmann, Yaron; Scheu, Christina; Kaplan, Wayne D.; Rühle, M.

doi:10.1126/science.1118611

Cited by 311 publications

(130 citation statements)

References 27 publications

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“…Given the purely additive contribution of each layer to the dielectric strength in our experimental configuration 33 , we might imagine a higher BOO in proximity to the interfaces, penetrating for a few nanometres. Such a length scale is larger than has been observed in metallic liquids in proximity to the crystal growth front 34 , where only a few atomic layers are affected. We were able to fit the interfacial excess in De N with a single exponential with a characteristic decay length of 5.9 ± 1.0 nm.…”

Section: Resultsmentioning

confidence: 78%

Supercooled liquids with enhanced orientational order

2012

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The nature of the glass transition, the transformation of a liquid into a disordered solid, still remains one of the most intriguing unsolved problems in materials science. Recent models rationalize crucial features of vitrification with the presence of medium-range ordered regions coexisting with the isotropic liquid. Here, in line with this prediction, we report an extraordinary enhancement in bond orientational order in ultrathin films of supercooled polyols, grown by physical vapour deposition. By varying the deposition conditions and the molecular size, we could tune the kinetic stability of the liquid phase enriched in bond orientational order towards conversion into the ordinary liquid phase. We observed a strong increase in the dielectric strength with respect to the ordinary supercooled liquid and slower structural dynamics, suggesting the existence of a metastable liquid phase with improved orientational correlations.

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Section: Resultsmentioning

confidence: 78%

Supercooled liquids with enhanced orientational order

2012

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“…It is reasonable to consider that the special structures are relevant to the specific heat increase. Oh et al experimentally observed ordered liquid aluminum atoms adjacent to the crystalline interface with sapphire [46]. Additionally, molecular dynamics simulations showed the formation of a dense (compressed) layer with a certain thickness at the interface between a solid nanoparticle and liquid molecules [30].…”

Section: Resultsmentioning

confidence: 99%

Anomalous Increase in Specific Heat of Binary Molten Salt-Based Graphite Nanofluids for Thermal Energy Storage

Kim¹,

Jo²

2018

Applied Sciences

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An anomalous increase of the specific heat was experimentally observed in molten salt nanofluids using a differential scanning calorimeter. Binary carbonate molten salt mixtures were used as a base fluid, and the base salts were doped with graphite nanoparticles. Specific heat measurements of the nanofluids were performed to examine the effects of the composition of two salts consisting of the base fluid. In addition, the effect of the nanoparticle concentration was investigated as the concentration of the graphite nanoparticles was varied from 0.025 to 1.0 wt %. Moreover, the dispersion homogeneity of the nanoparticles was explored by increasing amount of surfactant in the synthesis process of the molten salt nanofluids. The results showed that the specific heat of the nanofluid was enhanced by more than 30% in the liquid phase and by more than 36% in the solid phase at a nanoparticle concentration of 1 wt %. It was also observed that the concentration and the dispersion homogeneity of nanoparticles favorably affected the specific heat enhancement of the molten salt nanofluids. The dispersion status of graphite nanoparticles into the salt mixtures was visualized via scanning electron microscopy. The experimental results were explained according to the nanoparticle-induced compressed liquid layer structure of the molten salts.

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“…This is the case when ordering in the liquid [71,72] is necessary for crystallization [73]. The activation energy of crystallization in a number of metals and alloys is the same as for diffusion [74].…”

Section: Dendrite Growth In Undercooled Glass-forming Cu 50 Zr 50 Alloymentioning

confidence: 99%

Non-Equilibrium Solidification of Undercooled Metallic Melts

Herlach

2014

Metals

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Abstract:If a liquid is undercooled below its equilibrium melting temperature an excess Gibbs free energy is created. This gives access to solidification of metastable solids under non-equilibrium conditions. In the present work, techniques of containerless processing are applied. Electromagnetic and electrostatic levitation enable to freely suspend a liquid drop of a few millimeters in diameter. Heterogeneous nucleation on container walls is completely avoided leading to large undercoolings. The freely suspended drop is accessible for direct observation of rapid solidification under conditions far away from equilibrium by applying proper diagnostic means. Nucleation of metastable crystalline phases is monitored by X-ray diffraction using synchrotron radiation during non-equilibrium solidification. While nucleation preselects the crystallographic phase, subsequent crystal growth controls the microstructure evolution. Metastable microstructures are obtained from deeply undercooled melts as supersaturated solid solutions, disordered superlattice structures of intermetallics. Nucleation and crystal growth take place by heat and mass transport. Comparative experiments in reduced gravity allow for investigations on how forced convection can be used to alter the transport processes and design materials by using undercooling and convection as process parameters.

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Ordered Liquid Aluminum at the Interface with Sapphire

Cited by 311 publications

References 27 publications

Supercooled liquids with enhanced orientational order

Supercooled liquids with enhanced orientational order

Anomalous Increase in Specific Heat of Binary Molten Salt-Based Graphite Nanofluids for Thermal Energy Storage

Non-Equilibrium Solidification of Undercooled Metallic Melts

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