AZ80镁合金热变形过程组织演变的相场建模及应用研究

AZ80镁合金热变形过程组织演变的相场建模及应用研究摘要：

AZ80镁合金是一类优异的轻质高性能材料，具有广阔的应用前景。本文以AZ80镁合金为研究对象，采用相场建模方法，对材料在高温热变形过程中的组织演变进行了研究。首先，利用热力学模型构建合金的自由能函数，并使用一维相场模型对合金的初期微观组织进行建模。然后，结合ALE（ArbitraryLagrangian-EulerianMethod）方法，对合金在高温热变形过程中的微观组织演变进行了模拟，并分析了组织参数随时间的变化规律。研究结果发现，在高温下，镁合金中的分散相会随时间增长而演变成为大粒度的晶粒，同时晶界的面积也会增加。此外，组织参数的演变规律还与高温下金属材料内氧、氢等元素的行为有关。本文的研究成果有助于深入理解AZ80镁合金在高温下的微观组织演变规律，为研究高性能镁合金及其应用提供理论依据。

关键词：AZ80镁合金；相场模型；高温热变形；组织演变；ALE方法

Abstract:

AZ80magnesiumalloyisanexcellentlightweighthigh-performancematerialwithawiderangeofapplications.Inthispaper,AZ80magnesiumalloywasstudiedastheresearchobject,andtheorganizationevolutionofthematerialduringhightemperaturedeformationwasstudiedbyusingphasefieldmodelingmethod.Firstly,thefreeenergyfunctionofthealloywasconstructedbyusingthermodynamicmodels,andtheinitialmicrostructureofthealloywasmodeledusingone-dimensionalphasefieldmodel.Then,themicrostructureevolutionofthealloyduringhightemperaturedeformationwassimulatedbycombiningtheArbitraryLagrangian-EulerianMethod(ALE),andthechangelawofthemicrostructureparameterswithtimewasanalyzed.Theresearchresultsshowthatathightemperature,thedispersedphasesinthemagnesiumalloywillevolveintolarge-grainedcrystalswithtime,andtheareaofthegrainboundarieswillalsoincrease.Inaddition,theevolutionofmicrostructureparametersisalsorelatedtothebehaviorofelementssuchasoxygenandhydrogeninthemetalmaterialathightemperature.TheresearchresultsofthispaperwillhelptodeepentheunderstandingofthemicrostructureevolutionlawofAZ80magnesiumalloyathightemperatureandprovideatheoreticalbasisforthestudyandapplicationofhigh-performancemagnesiumalloy.

Keywords:AZ80magnesiumalloy;Phasefieldmodel;Hightemperaturedeformation;Organizationevolution;ArbitraryLagrangian-EulerianMethod(ALEHigh-temperaturedeformationandorganizationevolutionofAZ80magnesiumalloywerestudiedusingaphasefieldmodelincombinationwiththeArbitraryLagrangian-Eulerianmethod(ALE).Thesimulationsrevealedthebehaviorofoxygenandhydrogeninthemetalmaterialathightemperature,whichprovidedadeeperunderstandingofthemicrostructureevolutionlawofAZ80magnesiumalloy.

Thephasefieldmodelwasusedtosimulatethemicrostructureevolutionduringthehigh-temperaturedeformationofAZ80magnesiumalloy.Themodelwasbasedonthethermodynamicandkineticequationsthatgovernthephasetransformationandmassdiffusion.TheArbitraryLagrangian-Eulerianmethodwasusedtohandlethelargedeformationandthemeshdistortionduringthesimulation.

ThesimulationresultsshowedthatthedeformationtemperaturehadasignificanteffectonthemicrostructureevolutionofAZ80magnesiumalloy.Athighertemperatures,thenucleationofnewgrainswasfavored,leadingtoasmallergrainsizeandamorehomogeneousmicrostructure.Atlowertemperatures,however,thegraingrowthwaspredominant,resultinginalargergrainsizeandamoreheterogeneousmicrostructure.

Moreover,thesimulationalsorevealedthatoxygenandhydrogenhadaprofoundimpactonthemicrostructureevolutionofAZ80magnesiumalloyathightemperature.Oxygentendedtoaccumulateatthegrainboundaries,leadingtotheformationofoxideparticles,whilehydrogenwasmainlydissolvedinthemetalmatrix.Bothoxygenandhydrogenaffectedthematerialstrengthanddeformationbehavior,aswellasthemicrostructureevolutionofAZ80magnesiumalloy.

Inconclusion,thephasefieldmodelincombinationwiththeArbitraryLagrangian-EulerianmethodprovidedapowerfultooltostudythemicrostructureevolutionofAZ80magnesiumalloyathightemperature.Theresearchresultswillhelptodeepentheunderstandingofthematerialbehaviorandprovideatheoreticalbasisforthedevelopmentofhigh-performancemagnesiumalloysFurthermore,theresearchfindingsalsohavepracticalimplicationsfortheindustry.AZ80magnesiumalloyhasmanyapplicationsintheaerospace,automotive,andelectronicsindustries.Thealloypossessesexcellentqualitiessuchasahighstrength-to-weightratio,goodcastabilityandmachinability,andgoodcorrosionresistance.However,itsuseislimitedduetoitspoorhigh-temperatureperformanceandsusceptibilitytocreepdeformation.Therefore,understandingthematerialbehaviorofAZ80magnesiumalloyathightemperatureanditsmicrostructureevolutioniscrucialforthedevelopmentofhigh-performancemagnesiumalloysthatcanwithstandtemperatureextremes.

Throughthephasefieldmodelingapproach,theresearcherswereabletosimulatethedynamicbehaviorofAZ80magnesiumalloyduringdeformationandathightemperature.Theywereabletoinvestigatetheinfluenceofdifferentfactorssuchastemperature,strainrate,andmicrostructurefeaturesonthematerialpropertiesanddeformationbehaviorofthealloy.ThisinformationcanbeusedtooptimizetheprocessparametersduringthemanufacturingofAZ80magnesiumalloyandtopredictthematerialperformanceunderdifferentenvironmentalconditions.

Insummary,thisstudypresentsacomprehensiveanalysisofthemicrostructureevolutionofAZ80magnesiumalloyduringhigh-temperaturedeformationusingaphasefieldmodelingapproach.Thefindingsshedlightonthemechanismsinvolvedintheprocess,provideinsightsintothematerialbehavior,andoffervaluableinformationforthedevelopmentofhigh-performancemagnesiumalloys.Theresearchresultsareexpectedtohavewide-rangingapplicationsintheaerospace,automotive,andelectronicsindustries,amongothers,andpavethewayforfurtherresearchinthefieldofmagnesiumalloysInrecentyears,magnesiumalloyshavereceivedincreasingattentionaspotentiallightweightstructuralmaterialsduetotheirhighstrength-to-weightratio,excellentcastability,andgoodcorrosionresistance.However,thepracticalapplicationofmagnesiumalloysislimitedbytheirpoorductilityandlow-temperatureformability.High-temperaturedeformationisaneffectivewaytoimprovetheductilityandformabilityofmagnesiumalloysbycontrollingthemicrostructureevolutionandtexturedevelopmentduringdeformation.

Inthisstudy,aphasefieldmodelingapproachwasappliedtoinvestigatethemicrostructureandtextureevolutionofatypicalmagnesiumalloyAZ31duringhigh-temperaturedeformation.Thephasefieldmethodisapowerfultoolforsimulatingthecomplexmicrostructureevolutionandtexturedevelopmentinmaterialsundervariousdeformationconditions.Itisbasedonsolvingthetime-dependentevolutionequationsfororderparametersthatdescribethephasetransformationandrecrystallizationprocesses.

Thesimulationswereperformedforarepresentativematerialvolumeunderdifferentdeformationconditions,includinguniaxialcompression,torsion,andtensiledeformation.Theeffectsofdeformationparameterssuchasstrainrate,temperature,andinitialmicrostructureonthemicrostructureandtextureevolutionwereinvestigated.Thesimulationresultswerecomparedwithexperimentalobservationsandshowedgoodagreement.

Thesimulationresultsrevealedthatthemicrostructureevolutionandtexturedevelopmentduringhigh-temperaturedeformationofmagnesiumalloysaregovernedbycomplexmechanismsinvolvingdislocationslip,twinning,dynamicrecrystallization,andgraingrowth.Theformationofadeformationbandwasfoundtobetheprecursorofdynamicrecrystallization,andthetextureevolutionwascloselyrelatedtothedeformationmechanismsanddeformationparameters.

Thefindingsofthisstudyprovidenewinsightsintothedeformationbehaviorofmagnesiumalloysandoffervaluableinformationforimprovingtheirductilityandformability.Thephasefieldmodelingapproachcanbeextendedtoinvestigateothermagnesiumalloysanddeformationconditionsandcanbeusedasapredictivetoolforoptimizingtheprocessingparametersanddesigningnewmagnesiumalloysforspecificapplications.

Inconclusion,thisstudydemonstratestheimportanceofusingadvancedcomputationaltoolstounderstandthemicrostructureandtextureevolutionduringhigh-temperaturedeformationofmagnesiumalloys.Theresultsprovidefundamentalknowledgeforthedevelopmentof