Journal ArticleDOI
High-Speed imaging and analysis of the solidification of undercooled nickel melts
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In this article, an undercooled pure nickel was imaged at sufficiently high spatial resolution (64 × X 64 pixels) and temporal resolution (40,500 frames/s) to observe interface shape and motion at solidification velocities exceeding 45 m/s.Abstract:
Rapid solidification of undercooled pure nickel has been imaged at sufficiently high spatial resolution (64 ×X 64 pixels) and temporal resolution (40,500 frames/s) to observe interface shape and motion at solidification velocities exceeding 45 m/s. Imaging was of 8 g, quartz-enclosed melts at undercoolings of 70 to 300 K. Dendrite velocities within the melt were calculated from the surface velocities observed employing a simple geometric model of growth. Solidification was found to proceed invariably from a single nucleation point; growth velocity then followed an approximate power-law relationship with respect to undercooling up to some critical value ΔT*, where 150 K < ΔT* < 180 K. At higher undercoolings, velocity increased less rapidly than predicted by the power-law relationship and the interface morphology changed in appearance from angular to macroscopically smooth.read more
Citations
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Atomistic and continuum modeling of dendritic solidification
TL;DR: In this paper, a review of recent achievements in the dendrite modeling problem, using two distinct length scale approaches, are summarized, and it is demonstrated that when the atomistic and continuum level approaches are combined, accurate and parameter free predictions of dendritic growth velocities are possible.
Journal ArticleDOI
Linking Phase-Field and Atomistic Simulations to Model Dendritic Solidification in Highly Undercooled Melts
TL;DR: In this article, the authors simulate the crystallization of highly undercooled nickel melts using a computationally efficient phase-field model together with anisotropic properties recently predicted by molecular dynamics simulations, compared to experimental data and to the predictions of a linearized solvability theory that includes both capillary and kinetic effects at the interface.
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Kinetic coefficient of Ni solid-liquid interfaces from molecular-dynamics simulations
TL;DR: In this paper, the kinetics of isothermal crystallization and melting are studied for elemental Ni employing non-equilibrium molecular-dynamics simulations based on interatomic potentials of the embedded-atom-method form.
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New evidence for the dual origin of anomalous eutectic structures in undercooled Ni–Sn alloys: In situ observations and EBSD characterization
TL;DR: In this article, a high-speed camera was used to measure crystal growth velocities in the undercooled liquid by tracking the loci of the recalescence front.
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Structural Evidence for the Transition from Coupled to Decoupled Growth in the Solidification of Undercooled Ni-Sn Eutectic Melt
TL;DR: In this article, the structure morphologies of the sample surface as well as inside the sample were systematically examined, and a critical undercooling of 130 K was clearly revealed for the alloy.
References
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Book
Principles of Solidification
TL;DR: Solidification is the process by which a liquid is transformed into a crystalline solid as discussed by the authors, in which the solid that forms first is solvent rich as distinct from crystallisation, and the crystals that are formed are solute rich.
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Rapid dendrite growth in undercooled alloys
TL;DR: In this article, the theory of dendritic growth into undercooled alloy melts is extended to the case of large undercoolings, i.e. to high growth rates, by applying the results of the complete stability analysis of a plane interface to the tip of an Ivantsov dendrite.
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Physical Chemistry Of Process Metallurgy
TL;DR: The physical chemistry of process metallurgy is now as much the province of the physical chemist as the metallurgist as discussed by the authors, and the discussion at this meeting was devoted almost entirely to the high-temperature processes involved in the winning and refining of metals, and here it seems that advances will come mainly from the application of physical chemistry.
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Evidence of nonequilibrium processes in rapid solidification of undercooled metals.
TL;DR: Vitesses de solidification en fonction de la temperature de sous-refroidissement pour Ni pur et les alliages Cu−Ni.
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Measurements of ultrarapid solidification rates in greatly undercooled bulk melts with a high speed photosensing device
TL;DR: In this paper, the growth velocities up to 70 m s−1 were deduced from the measured recalescence times, and the results were discussed within theoretical predictions for dendritic growth in highly undercooled melts.