Cellular/dendritic transition during unsteady-state unidirectional solidification of Sn–Pb alloys

Rocha, Otávio Fernandes Lima da; Siqueira, Claudio; Garcia, Amauri

doi:10.1016/s0921-5093(02)00581-6

Cited by 72 publications

(53 citation statements)

References 21 publications

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“…A number of directional solidification studies have been reported in the last decades to point out the effect of microstructure upon the mechanical properties, and different approaches and equations have been used with the purpose of modeling both theoretically and experimentally the primary and secondary dendrite arm spacings as a function of alloy solute concentration (C O ), transient metal-mold heat transfer coefficient (h i ), tip growth rate (V L ), temperature gradient (G L ) ahead of the macroscopic solidification front, tip cooling rate (T R ) in the melt, type of mold and melt superheat [14][15][16][17][18][19][20][21][22][23][24][25] . Most studies have shown that for steady or unsteady growth conditions, the primary dendrite arm spacings decrease as the solidification rate or temperature gradient increases; however, there is no agreement in the literature regarding the effect of the alloy solute content on primary spacings.…”

Section: Introductionmentioning

confidence: 99%

“…It has been observed, however, that these predictive theoretical models did not generate the experimental observations concerning the unsteady-state solidification of Al-Cu and Sn-Pb alloys 20 . The insertion of analytical expressions for V L and T R into experimental equations has been proposed in order to establish experimental formulae that relate cellular 19,22 and dendritic 20,23 spacings with the unsteady-state solidification variables. On the other hand, various numerical methods including cellular automata [26][27][28] , front-tracking methods [29][30][31] , phase field techniques [32][33][34] and level set methods [35][36] have been developed to study the growth of dendrites.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of the Al-3wt.%Si alloy in unsteady-state horizontal directional solidification

et al. 2013

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The main purpose of this paper is to investigate both the columnar to equiaxed transition and primary dendritic arm spacings of Al-3wt.%Si alloy during the horizontal directional solidification. The transient heat transfer coefficient at the metal-mold interface is calculated based on comparisons between the experimental thermal profiles in castings and the simulations provided by a finite difference heat flow program. Simulated curve of the interfacial heat transfer coefficient was used in another numerical solidification model to determine theoretical values of tip growth rates, cooling rates and thermal gradients that are associated with both columnar to equiaxed transition and primary dendritic arm spacings. A good agreement was observed between the experimental values of these thermal variables and those numerically simulated for the alloy examined. A comparative analysis is carried out between the experimental data of this work and theoretical models from the literature that have been proposed to predict the primary dendritic spacings. In this context, this study may contribute to the understanding of how to manage solidification operational parameters aiming at designing the microstructure of Al-Si alloys.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of the Al-3wt.%Si alloy in unsteady-state horizontal directional solidification

et al. 2013

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“…On the other hand, the analysis of these structures in the non-steady-state regime is scarce in the literature, despite its importance, since it encompasses the majority of industrial solidification processes. Rocha et al [19] have studied the cellular to dendritic transition during the transient directional solidification of Sn-Pb hypoeutectic alloys. They have found that such transition can be observed in the range of compositions between 2 and 3 wt pct Pb.…”

Section: Introductionmentioning

confidence: 99%

Cellular/Dendritic Transition and Microstructure Evolution during Transient Directional Solidification of Pb-Sb Alloys

Rosa

Spinelli

Ferreira

et al. 2008

Metall Mater Trans A

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Recent studies of lead-antimony alloys, used for the production of positive electrodes of leadacid batteries, have assessed the influences of both the microstructural morphology and of solute redistribution on the surface corrosion resistance in sulfuric acid solution, and have shown that cellular structures and dendritic structures have different responses on the corrosion rate of such alloys. The present article focuses on the search of adequate solidification conditions (alloy composition, cooling rate, and solidification velocity), which determine the occurrence of a microstructural transition from the cellular to the dendritic regime during the transient unidirectional solidification of hypoeutectic Pb-Sb alloys and on the microstructural evolution after such transition. The experimental data refers to the solidification of four hypoeutectic Pb-Sb alloys (2.2, 2.5, 3, and 6.6 wt pct Sb) and of the eutectic composition. The experimental results include transient metal/mold heat-transfer coefficients, liquidus isotherm velocity, cooling rate, and cellular and dendritic spacings. It was found that the cooling rate dependence on cellular and primary dendritic spacings is characterized by an experimental law of the form k 1 ¼ AÁ _ T À0:55 ; which seems to be independent of composition where A = 60 represents the alloys undergoing a cellular growth and A = 115 can describe the dendritic growth. The sudden change on such multiplier has occurred for the Pb 2.2 wt pct Sb alloy, i.e., for the cellular/ dendritic transition.

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“…The geometry of typical cell spacing is obtained from previous and present works. 17,18) Figure 8(a) also shows that the TE current emanates from the tips and passes down to the root. Figure 8(a) shows the TEMC in the mushy zone.…”

Section: (8)mentioning

confidence: 99%

Experimental and Numerical Investigations of the Multi-scale Thermoelectromagnetic Convection on the Microstructure during Directionally Solidified Sn-5wt%Pb Alloys

Fautrelle

Ren

et al. 2017

ISIJ Int.

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Cellular/dendritic transition during unsteady-state unidirectional solidification of Sn–Pb alloys

Cited by 72 publications

References 21 publications

Characterization of the Al-3wt.%Si alloy in unsteady-state horizontal directional solidification

Characterization of the Al-3wt.%Si alloy in unsteady-state horizontal directional solidification

Cellular/Dendritic Transition and Microstructure Evolution during Transient Directional Solidification of Pb-Sb Alloys

Experimental and Numerical Investigations of the Multi-scale Thermoelectromagnetic Convection on the Microstructure during Directionally Solidified Sn-5wt%Pb Alloys

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