Influence of melt convection on the columnar to equiaxed transition and microstructure of downward unsteady-state directionally solidified Sn-Pb alloys

dc.creatorSpinelli, JE
dc.creatorFerreira, IL
dc.creatorGarcia, A
dc.date2004
dc.dateDEC 14
dc.date2014-11-15T06:00:24Z
dc.date2015-11-26T16:09:37Z
dc.date2014-11-15T06:00:24Z
dc.date2015-11-26T16:09:37Z
dc.date.accessioned2018-03-28T22:58:13Z
dc.date.available2018-03-28T22:58:13Z
dc.identifierJournal Of Alloys And Compounds. Elsevier Science Sa, v. 384, n. 41671, n. 217, n. 226, 2004.
dc.identifier0925-8388
dc.identifierWOS:000225308800037
dc.identifier10.1016/j.jallcom.2004.04.098
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/80209
dc.identifierhttp://www.repositorio.unicamp.br/handle/REPOSIP/80209
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/80209
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1266666
dc.descriptionA combined theoretical and experimental approach is developed to quantitatively determine the solidification thermal parameters: transient heat transfer coefficients, tip growth rates and cooling rates during downward unsteady state solidification of hypoeutectic Sn-Pb alloys. For the growth conditions examined, solid in the top and melt below, with gravity pointing down, the rejection of solute into the melt during solidification results in increased melt density. The resulting thermosolutal convection can start in the melt both within the interdendritic region and ahead of the dendrite array. The experimental results have shown that melt convection may be causing pileup of fractioned dendritic arms, which must stimulate the CET occurrence. The results have supported a criterion recently proposed based on a critical cooling rate. For upward unidirectional condition, this critical value was found to about 0.014 K/s for hypoeutectic Sn-Pb alloys. In the present study, in conditions of downward solidification, melt convection seems to favor the structural transition, which is anticipated and occurs for a critical cooling rate of about 0.03 K/s, for any of three hypoeutectic alloys experimentally examined. Primary dendritic arm spacings have been affected by the direction of growth decreasing in conditions of downward vertical solidification when compared with those grown vertically upwards. A tendency of reduction of secondary dendritic arms has also been observed for the Sn 5 wt.% Pb alloy solidified downwards when compared with those grown vertically upwards. (C) 2004 Elsevier B.V. All rights reserved.
dc.description384
dc.description41671
dc.description217
dc.description226
dc.languageen
dc.publisherElsevier Science Sa
dc.publisherLausanne
dc.publisherSuíça
dc.relationJournal Of Alloys And Compounds
dc.relationJ. Alloy. Compd.
dc.rightsfechado
dc.rightshttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dc.sourceWeb of Science
dc.subjectdownward unsteady-state solidification
dc.subjectcolumnar to equiaxed transition
dc.subjectdendrite arm spacings
dc.subjectSn-Pb alloys
dc.subjectmelt convection
dc.subjectAl-cu Alloys
dc.subjectBinary-alloys
dc.subjectArm Spacings
dc.subjectHeat-flow
dc.subjectParameters
dc.subjectIngots
dc.subjectPrediction
dc.subjectCastings
dc.subjectGrowth
dc.titleInfluence of melt convection on the columnar to equiaxed transition and microstructure of downward unsteady-state directionally solidified Sn-Pb alloys
dc.typeArtículos de revistas


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