convection in the two phase zone of solidifying alloys英文文献资料

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1、ConvectionintheTwo-PhaseZoneofSolidifyingAlloysA.L.MAPLESandD.R.POIRIERTheanalysisisapplicabletoalloysolidificationwhichproceedshorizontallytothecenterofamold.Themodelfollowsthegrowthofthesolid-liquidzoneadjacenttothechillface(theinitialtransient),themovementofthez

2、oneacrossthemold,andtheregionoffinalsolidificationadjacenttothecenterline(thefinaltransient).Duringsolidificationthedensityoftheliquidvariesacrossthetwo-phasezone.Consequently,thereisnaturalconvectionwhichistreatedasflowthroughaporousmedium.Theequationsforconvectio

3、narecoupledwiththeequationofsoluteredistributionbetweenthephasesinordertocalculatemacrosegregationaftersolidificationiscomplete.Resultswerecomputedforalloyswhichshow:(1)"inversesegregation"atacooled-surface;(2)macrosegregationresultingfromsolidificationwiththeiniti

4、altransient,aperiodwithacompletetwo-phasezone,andafinaltransient;and(3)macrosegregationwhenthewidthofthetwo-phasezoneexceedsthesemi-widthofthemold.I.INTRODUCTIONThestructureoftheS/LzoneisshowninFigure2(a)inwhichthesolidphaseisshownasdendrites.Figure2(a)THISpaperdes

5、cribesamodelofbinaryalloyswhichdoesillustratethemannerinwhichvolumefractionofsolidifyhorizontally.ThemajorpurposeofthemodelistosolidvarieswithintheS/Lzone,andthisisplottedincalculatemacrosegregationwhichresultsfromthecon-Figure2(b).Sincethereisredistributionofsolut

6、ebetweenvectionofinterdendriticliquidduringsolidification.Thisthetwophasesduringsolidification,thetemperatureandconvection,whichisdrivenbysolidificationcontractionscompositionoftheinterdendriticliquidvaryasdepictedinandbygravity,ismodeledasflowthroughaporousme-Figu

7、res2(c)and2(d),respectively.dium.Themodelcanbeusedtoobtain(1)thepressureThemathematicalformulationisbaseduponthatgivenbyfield,(2)thevelocityfield,and(3)thesolutefluxintheMehrabianetal.6forunidirectionalandhorizontalsolidi-solidplusliquidzoneduringsolidification.Wit

8、hthesees-fication,butMehrabianetal.didnotanalyzethetransientstablished,macrosegregationaftercompletesolidificationisoftheS/Lzone.Inalaterwork,Fuj