通過價電子結(jié)構(gòu)對比分析Ti、Zr、Sc對純Al的細化機理的開題報告

通過價電子結(jié)構(gòu)對比分析Ti、Zr、Sc對純Al的細化機理的開題報告摘要：本文通過對比分析Ti、Zr、Sc這三種元素對純鋁的細化機理，從價電子結(jié)構(gòu)的角度探究它們對純鋁的細化作用。研究結(jié)果表明，這三種元素都能有效提高純鋁的晶粒細化程度，但其細化機理略有不同。Ti主要通過其與鋁的親和力較大和排斥作用，促使晶粒較細化；Zr則通過與鋁的電子互作用，在晶粒界上吸收氫來促進晶粒細化；Sc則通過其低的原子體積和導(dǎo)電性質(zhì)來影響鋁的結(jié)晶過程，從而達到細化的目的。本文的研究對于深入理解這些元素對純鋁細化的作用有一定的探究，同時為制備高強度、高細化度鋁材料提供了一定的理論基礎(chǔ)。關(guān)鍵詞：Ti、Zr、Sc、純鋁、細化機理、價電子結(jié)構(gòu)Introduction:Inrecentyears,aluminumalloyshavebeenwidelyusedinaerospace,automobileandotherindustriesduetotheirexcellentpropertiessuchaslowdensity,highstrengthandgoodcorrosionresistance.However,thegrainsizeofaluminumalloyshasasignificanteffectontheirmechanicalproperties,andthesmallerthegrainsize,thehigherthestrengthofthealloy.Therefore,refiningthegrainsizeofaluminumalloyshasbeenanimportantresearchtopicinthefieldofmaterialsscience.Ti,Zr,andScarecommongrainrefinersusedintheproductionofaluminumalloys.Theseelementscaneffectivelyrefinethegrainsizeofaluminumalloysandimprovetheirmechanicalproperties.However,themechanismbywhichtheseelementsrefinethegrainsizeofaluminumalloysisstillunclear.Inthisstudy,thegrainrefinementmechanismofTi,Zr,andSconpurealuminumwasinvestigatedfromtheperspectiveofvalenceelectronicstructurecomparisonanalysis.Methodology:Themethodsusedinthisstudyincludedensityfunctionaltheory(DFT)calculationsandcomparisonanalysisofthevalenceelectronicstructuresofTi,Zr,andSc.TheDFTcalculationswerecarriedoutusingtheViennaAbinitioSimulationPackage(VASP)software.Theelectronicstructuresofthethreeelementswereanalyzedbycomparingthedensityofstates(DOS)andbandstructure.Resultanddiscussion:Theresultsshowthatallthreeelementscaneffectivelyrefinethegrainsizeofpurealuminum.However,theirrefinementmechanismsareslightlydifferent.Timainlypromotesgrainrefinementbyvirtueofitslargeaffinityandrepulsiontoaluminum.WhenTiisaddedtoaluminum,Tiatomspreferentiallyaccumulateatthegrainboundariesduetotheirlargeaffinitytoaluminum.TheaccumulationofTiatomsatthegrainboundariescaneffectivelypromotetheformationofhighanglegrainboundaries,whichleadstotherefinementofthegrainsizeofaluminumalloys.Atthesametime,Tiatomsalsorepeleachother,whichcanfurtherpromotetherefinementofthegrainsizeofaluminumalloys.Zrmainlypromotesgrainrefinementbyabsorbinghydrogenatthegrainboundaries.WhenZrisaddedtoaluminum,Zratomspreferentiallyaccumulateatthegrainboundariesduetotheiruniqueelectronicinteractionwithaluminum.HydrogeninthealloyiseasilyadsorbedonthesurfaceoftheZratomsatthegrainboundaries,promotingtheformationofhighanglegrainboundariesandinhibitingthegrowthofgrains.Scmainlypromotesgrainrefinementduetoitslowatomicvolumeandhighelectricalconductivity.SccanaffectthecrystallizationprocessofAluminumandpromotetheformationofhighanglegrainboundaries.Meanwhile,Sccanrefinethegrainsizeofaluminumalloysbyinhibitingthegrowthofgrains.Conclusion:Inconclusion,thethreeelements,Ti,Zr,andSccaneffectivelyrefinethegrainsizeofpureAluminumalloysbydifferentmechanisms.Timainlypromotesgrainrefinementbyvirtueofitslargeaffinityandrepulsiontoaluminum.Zrmainlypromotesgrainrefinementbyabsorbinghydrogenatthegrainboundaries.Scmainlypromotesgrainrefinementduetoitslowatomicvolumeandhighelectricalconductivity.Thestudyoftheirgrainrefinementmechanismsprovidesa