Effect of DH treatment on microstructure and mechanical properties of an LM28-0.3wt.%Nd hypereutectic aluminum silicon alloy

(整期优先)网络出版时间:2007-06-16
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Inthisarticle,anovelheattreatmentmethod,deformationheat(DH)treatment(extrusion+aging),wasemployedonahypereutecticaluminumsiliconalloy(LM28-0.3wt.%Nd),anditseffectonmicrostructureandmechanicalpropertiesofthisalloywasinvestigated.ItcanbeconcludedthattheeutecticmicrostructuredisappearsaftertheDHtreatment,inthemeantimethemorphologyofα(Al)solidsolutionwastransformedfromfir-treeandcellulartoequiaxed,Siwasrefinedwithgrainsizesofabout1-10μmanddistributeddispersedly,evensomeofthembecameglobularshape,whichcanreducestressaccumulationeffectively.MechanicalpropertiestestindicatedthattheDHtreatmentcouldsignificantlyimprovetheroom-temperaturestrengthandhavelittleeffectonthehigh-temperaturestrengthofLM28-0.3wt.%Ndalloy.Thefracturemechanismisductilefracturebyfracturemorphologyanalysis.