反重力铸造条件下氢含量和冷却速度对铝合金铸件中孔洞的影响

··。、、。、、[1-2]、、、、[3-4]。[5-6]。[7]。。[8-12]。Counter-gravityWithdrawalCastingCWC。11.1A356Al-7%Si-0.4%Mg。4.5kgA356760℃720℃30min0.06%Sr1。!!!!!!!!!!!!!!!!·211189：。、、。：：TG146.2+1：A：1001-4977200903-0205-05WANGHui-ping,ZHAOLei,ZHOUBiao,LIAOHeng-cheng,PANYe（SchoolofMaterialsScienceandEngineering,SoutheastUniversity,Nanjing211189,Jiangsu,China）Abstract：FourAl-Sialloyspecimenswithdifferenthydrogencontentwerefabricatedbycounter-gravitycasting,andtheeffectsofhydrogencontentandcoolingrateonformationofporosityinthealloywereinvestigated.Theresearchshowsthathydrogencontentplaysacrucialroleonporositydefect.Atsamesolidificationcondition,meltwithhighhydrogencontentisliabletoformpores;asthehydrogencontentbecamehigher,thenumberofporesandvolumefractionofporesincrease.Aslongasthehydrogencontentislowenough,itishardtoformbigporesevenifmeltfeedingispoor.Coolingratealsoexertsanimportantinfluenceontheformationofpores.Rapidcoolingcaneffectivelydecreasethenumberandsizeofpores;intheprocessofsolidification,hydrogencontentandcoolingratecorporatelydeterminethenumber,sizeandvolumefractionofpores.Keywords：counter-gravitycasting;hydrogencontent;coolingrate;Al-Sialloy;porosityEffectofHydrogenContentandCoolingRateonPorosityinAluminumAlloyPartsbyCounter-GravityCasting：50771031。：2008-11-072008-12-26。：1982-。[e-mail].2009Vol.58No.3FOUNDRY··1.2CWC1。CWC0.053mm/s20mm、170mm。8kPa。1.32。5020。。10。22.1RosenthalLipson[13]、。720℃20s8kPa1.5min1ml/100g。2。V=100×p2×1/D-1/D0/p1ml/100g1p2———8kPap1———101.3kPaD———g/mlD0———A3562.688g/ml[14]。230min15min15min。2h0.0429ppm。2.210、0.5mm、0.5mm。3。33。33L、UK、P、K、P3L、U23K1、P1、2Table2Resultsofhydrogenleveltestedbydepressedcastingmethodml/100gppm1ppm=10×ρ×1ml/100g。/ml·10-2g-10.05600.0465ppm0.05710.0474ppm0.27940.2311ppm0.33010.2740ppmKPLU/g29.1325.9723.0729.42/ml11.09.89.312.22Fig.2Sketchofselectingmethodofcrosssection1Table1TreatmentsofdifferentmeltsU2hK30minP15minLFOUNDRYMar.2009Vol.58No.31Fig.1Schematicofthecounter-gravitycastingdeviceV··4×10Fig.4Macrographsofcrosssections10×aK1bK2cK3dU1eU2fU33Table3Resultsofporosityinsamplesoffourdifferentmelts/%//·mm-2KPLU/ppm0.04650.04740.23110.274010.1500.0670.1330.15820.1510.2101.8012.45730.1080.0560.6170.830100002007273001230.620.810.490.5410.670.680.692.1020.701.480.380.48L1、U1K2、P2K3、P3L、U23K、PL、U、90%。。42[9]。11。23L、U23。2.3K1K1。410KU。K1、K2K3U1U2U3505a。3Fig.3Relationshipbetweenhydrogencontentandporosityofthewholetestbar：··25b。。650。KUUKKK100μmU100~200μmK。KUUK。21。23322。6231123。。。5Fig.5MacrographsofbigporesincrosssectionsunderhighmagnificationaU2bL26Fig.6MacrographsofsmallporesincrosssectionsaK1bK2cK3dU1eU2fU3。3。。。。15~20minFOUNDRYMar.2009Vol.58No.3··。。。、、。：[1].———[J].2001436-41.[2].[J].20036384-386.[3].[J].19981/223-26.[4].[J].1995585-97.[5]WangQi-guiApelianDLadosDA.FatiguebehaviorofA356/357aluminumcastalloys.PartII-Effectofmicrostructuralconstituents[J].LightMetals20011173-84.[6]WangQi-guiJonesPEOsborneM.AdvancesinaluminumcastingtechnologyII[M].USASMInternationalMaterialsPark200275-84.[7]LiYMLiRD.Effectofthecastingprocessvariablesonmicroporosityandmechanicalpropertiesinaninvestmentcasting[J].TechofAdvancedMater20012277-280.[8].[J].200036133-36.[9].[J].2002745-49.[10]SamuelAMSarnuelFH.EffectofmelttreatmentsolidificationconditionsandporositylevelonthetensilepropertiesofA3192endchillaluminumcasting[J].JMaterSci1995304823-4833.[11]RoyNZhangLLouchezPR.PorosityformationinAl-9wtpctSi-wtpctCusystemmeasurementofporosity[J].MaterSci1996311243-1254.[12]RoyNLouchezPRSamuelFH.PorosityformationinAl-wtpctSi-wtpctCualloysystem[J].JMaterSci1996314725-4730.[13]RosenthalHLipsonS.Measurementofgasinmoltenaluminum[J].AFSTrans.199563301-305.[14]SaigalA.Stressandstraindistributionsintwophasealuminum-siliconalloy[J][e-mail]：