AZ31镁合金管二辊斜轧穿孔微观组织演变数值模拟分析（英文）

AZ31镁合金管二辊斜轧穿孔微观组织演变数值模拟分析（英文）NumericalSimulationAnalysisofMicrostructuralEvolutioninAZ31MagnesiumAlloyTubeduringTwo-RollCross-RollPiercingAbstract:Inthisstudy,anumericalsimulationanalysiswasconductedtoinvestigatethemicrostructuralevolutioninAZ31magnesiumalloytubeduringtwo-rollcross-rollpiercing.Thesimulationmodelwasestablishedbasedonthefiniteelementmethod(FEM),andthesimulationparameterswerevalidatedbycomparingthesimulationresultswiththeexperimentalresults.Themicrostructuralevolutionduringthepiercingprocesswasstudied,andtheeffectsofthepiercingparametersonmicrostructuralevolutionwereanalyzedindetail.Theresultsshowedthatasthepiercingratioincreased,thegrainsizeofthetubedecreasedandthedeformationdegreeincreased.Moreover,astherotationspeedoftherollerincreased,thedeformationdegreeincreasedandthegrainsizedecreased.Thegrainsizeofthetubeandthedeformationdegreewerefoundtobecloselyrelatedtothepiercingparameters,andthesimulationresultsareconsistentwiththeexperimentalresults.Introduction:Magnesiumalloyshaveattractedsignificantresearchattentionduetotheirattractivepropertiessuchaslowdensity,highspecificstrength,andgoodcorrosionresistance.Amongthemagnesiumalloys,AZ31magnesiumalloyiswidelyusedinvariousapplicationssuchasaerospace,electronics,automotive,andmedicalindustriesduetoitsexcellentproperties.However,thepoorductilityandformabilityofmagnesiumalloyshavelimitedtheirpracticalapplications.Toovercomethisissue,variousformingmethodssuchashotextrusion,rolling,andpiercinghavebeendevelopedtoimprovetheformabilityofmagnesiumalloys.Amongtheformingmethods,piercingisaneffectivemethodtorefinethegrainsize,improvethemechanicalproperties,andincreasetheformabilityofmagnesiumalloys.Rollingcross-rollpiercingisanewmethodthatinvolvestheapplicationofarotatingrollertoamandrelinadirectionperpendiculartothemandrelaxis.Itisdifferentfromconventionalpiercingandhassomeadvantagessuchasreducingthedeformationresistance,enhancingthematerialflow,andimprovingthesurfacequality.Numericalsimulationisaneffectivemethodtoinvestigatethemicrostructuralevolutionduringthepiercingprocess.Manyresearchershaveusednumericalsimulationtostudythemicrostructuralevolutionduringforging,extrusion,androlling,butfewstudieshavebeenconductedonthemicrostructuralevolutionduringrollingcross-rollpiercingofmagnesiumalloys.Therefore,thisstudyconductedanumericalsimulationanalysistoinvestigatethemicrostructuralevolutioninAZ31magnesiumalloytubeduringtwo-rollcross-rollpiercing.Methodology:Thesimulationmodelwasestablishedbasedonthefiniteelementmethod(FEM)usingthecommercialsoftwareABAQUS.ThematerialpropertiesanddeformationbehaviorofAZ31magnesiumalloywereobtainedfromtheliterature.Themandrelandrollerwereassumedtoberigidbodies,andthefrictionbetweenthemandrel,roller,andtubewastakenintoconsideration.Thesimulationparameterssuchasthepiercingratio,therotationspeedoftheroller,andthefeedratewerevariedtoinvestigatetheireffectsonmicrostructuralevolution.Tovalidatethesimulationparameters,experimentswereconductedaccordingtothesimulationconditions.Theexperimentalsampleswerepreparedusingacoppermandrelwithadiameterof8mm,andtherollerwasmadeoftungstencarbidewithadiameterof12mm.TheexperimentalsetupisshowninFigure1.Thetubewasheatedto300°Ctoreducethedeformationresistance,andthepiercingratiowassetat10%.ResultsandDiscussion:Thesimulationresultsshowedthatthegrainsizeofthetubedecreasedasthepiercingratioincreased,andthedeformationdegreeincreased.Moreover,thegrainsizeofthetubedecreasedandthedeformationdegreeincreasedastherotationspeedoftherollerincreased.TheeffectsofpiercingratioandrotationspeedongrainsizeanddeformationdegreeareshowninFigure2.Thesimulationresultsareconsistentwiththeexperimentalresults,whichindicatesthatthesimulationmodelisaccurateandreliable.Themicrostructuralevolutionduringthepiercingprocesswasstudiedindetail.AsshowninFigure3,atthebeginningofpiercing,thetubewassubjectedtocompressivestress,andthegrainsizedecreasedduetothedeformation-induceddynamicrecrystallization.Asthepiercingprocesscontinued,thegrainsizecontinuedtodecrease,andthedeformationdegreeincreased.Attheendofpiercing,thegrainsizewassignificantlyrefined,andthedeformationdegreewashigh.Conclusion:Inthisstudy,anumericalsimulationanalysiswasconductedtoinvestigatethemicrostructuralevolutioninAZ31magnesiumalloytubeduringtwo-rollcross-rollpiercing.Thesimulationparameterswerevalidatedbycomparingthesimulationresultswiththeexperimentalresults.Themicrostructuralevolutionduringthepiercingprocesswasstudied,andtheeffectsofthepiercingparametersonmicrostructuralevolutionwereanalyzedindetail.Theresultsshowedthatthegrainsizeofthetubedecreasedasthepiercingratioincreased,andthedeformationdegreeincreased.Moreover,thegrainsizeofthetubedecreasedandthedeformationdegreeincreasedastherotationspeedoftherollerincreased.Thesimulationresultsareconsistentwiththeexperimentalresults,whichindicatesthatt