Mushy Layer Formation during Solidification οf Binary Alloys from a Cooled Wall: the Role of Boundary Conditions

Аlexandrova, Irina V.; Alexandrov, Dmitri V.; Aseev, D.L.; Bulitcheva, S. V.

doi:10.12693/aphyspola.115.791

Cited by 58 publications

(35 citation statements)

References 7 publications

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“…The essential role playing by the so-called contact layer (air gap) is considered in the current simulation analogously to some models considering both the mushy zone and contact layer influences on the ingot structure formation, [3][4][5].…”

Section: Mathematical Prediction Of Structural Transformationsmentioning

confidence: 99%

Structural Transformations Versus Hard Particles Motion in the Brass Ingots

Wołczyński

Ivanova

Kwapisiński

et al. 2017

Archives of Metallurgy and Materials

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A mathematical method for the forecast of the type of structure in the steel static ingot has been recently developed. Currently, the method has been applied to structural zones prediction in the brass ingots obtained by the continuous casting. Both the temperature field and thermal gradient field have been calculated in order to predict mathematically the existence of some structural zones in the solidifying brass ingot. Particularly, the velocity of the liquidus isotherm movement and thermal gradient behavior versus solidification time have been considered. The analysis of the mentioned velocity allows the conclusion that the brass ingots can evince: chilled columnar grains-, (CC), fine columnar grains-, (FC), columnar grains-, (C), equiaxed grains zone, (E), and even the single crystal, (SC), situated axially. The role of the mentioned morphologies is analyzed to decide whether the hard particles existing in the brass ingots can be swallowed or rejected by the solid / liquid (s/l) interface of a given type of the growing grains. It is suggested that the columnar grains push the hard particles to the end of a brass ingot during its continuous casting.

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Section: Mathematical Prediction Of Structural Transformationsmentioning

confidence: 99%

Structural Transformations Versus Hard Particles Motion in the Brass Ingots

Wołczyński

Ivanova

Kwapisiński

et al. 2017

Archives of Metallurgy and Materials

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“…Therefore, the boundary conditions connected with the air gap are formulated, analogously, as in the model for the mushy zone formation, [3].…”

Section: Introductionmentioning

confidence: 99%

Some Similarities / Differences between Steel Static and Virtual Brass Static Casting

Kwapisiński

Ivanova

Kania

et al. 2017

Archives of Foundry Engineering

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An innovative method for determining the structural zones in the large static steel ingots has been described. It is based on the mathematical interpretation of some functions obtained due to simulation of temperature field and thermal gradient field for solidifying massive ingot. The method is associated with the extrema of an analyzed function and with its points of inflection. Particularly, the CET transformation is predicted as a time-consuming transition from the columnar-into equiaxed structure. The equations dealing with heat transfer balance for the continuous casting are presented and used for the simulation of temperature field in the solidifying virtual static brass ingot. The developed method for the prediction of structural zones formation is applied to determine these zones in the solidifying brass static ingot. Some differences / similarities between structure formation during solidification of the steel static ingot and virtual brass static ingot are studied. The developed method allows to predict the following structural zones: fine columnar grains zone, (FC), columnar grains zone, (C), equiaxed grains zone, (E). The FCCT-transformation and CET-transformation are forecast as sharp transitions of the analyzed structures. Similarities between steel static ingot morphology and that predicted for the virtual brass static ingot are described.

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“…The microstructure predictions in solidification processes have the deep scientific and practical roots (see [1][2][3][4][5] and references therein). A development of experimental methods in solidification processing made possible to reach a much broader range of measurable crystal growth velocities, temperature gradients and cooling rates [6].…”

Section: Introductionmentioning

confidence: 99%

A relaxation time of secondary dendritic branches to their steady-state growth

Титова

Alexandrov

Galenko

2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. In the present article, we use the selection theory to estimate the non-stationarity time of evolving dendrites to their steady-state growth. IntroductionThe microstructure predictions in solidification processes have the deep scientific and practical roots (see [1][2][3][4][5] and references therein). A development of experimental methods in solidification processing made possible to reach a much broader range of measurable crystal growth velocities, temperature gradients and cooling rates [6]. For instance, splats and films can be quenched with the cooling rate of the order of 10 7 K/s, the temperature gradients can have the order of 10 8 K/s in laser annealing of sample surfaces, and containerless methods of droplets processing provide the deep undercoolings having the values of 200-400 K prior to the primary crystallization. A large driving force for transformation, arising in such methods, leads to fast solidification from a liquid metastable state as well as the high-speed solid-state transformations of metastable crystalline phases [7]. For instance, the experimentally measured solidification velocity has the order of 10 −1 − 10 2 m/s in droplets processed by the electromagnetic levitation facility [7,8]. As such, the total duration of primary solidification in small droplets is rather short and estimated as [8]: 10 −5 − 10 −3 s.For the analytical calculations of rapid solidification regimes and theoretical estimations of microstructural parameters of dendritic and eutectic crystals, different models of non-equilibrium crystallization are used, as a rule, formally developed for the steady state scenario [9][10][11]. However, the steady state approximation for conditions of rapid solidification of small samples (films, splats, droplets) is questionable and such approach is often criticized. A very common view is that a steady state scenario may be expected to exist but not in rapidly solidifying small samples [12]: the stationary regime of solidification can be reached at long times that is possible in usual experimental circumstances (directional solidification) or well-known classic technologies (continuous casting and low intensive brazing). In other words, during the short periods of time, the steady state is not achieved and, consequently, the quasi-stationary approximation in modeling of rapid solidification does fail. The detailed calculations of solidification regimes lead, however, to the remarkable behavior of the transient time between the non-stationary and stationary regimes of solidification: the non-stationary time sharply depends on the interface

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Mushy Layer Formation during Solidification οf Binary Alloys from a Cooled Wall: the Role of Boundary Conditions

Cited by 58 publications

References 7 publications

Structural Transformations Versus Hard Particles Motion in the Brass Ingots

Structural Transformations Versus Hard Particles Motion in the Brass Ingots

Some Similarities / Differences between Steel Static and Virtual Brass Static Casting

A relaxation time of secondary dendritic branches to their steady-state growth

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