AZ80镁合金管材热挤压成形及组织演变研究

沈阳理工大学硕士学位论文AZ80镁合金管材热挤压成形及组织演变研究姓名：赵根发申请学位级别：硕士专业：@指导教师：王忠堂2011211Gleeble-2000AZ80260-4100.001s-1-10s-1.2AZ80AZ803MSC.MarcAZ804AZ80AZ80,,,AZ805AZ8018.239036060°70°AZ8050834008AbstractWithmanyadvantages,includinglowspecificgravity;highspecificstrength,specificrigidity,dampingcapacity,processability;excellentthermalconductivity,electromagneticshieldingandrecyclability,magnesiumalloysareconsideredaseco-structuralmetalmaterialinthe21stcenturyandinterestmanyresearchers.Themainresearchincludessixpartsasfollows.1.Inthepresentstudy,hotcompressiontestsofAZ80magnesiumalloywereperformedonGleeble2000atstrainrates0.001-10s-1anddefomationtemperatures260-410,respectively.Theinfluenceoftheparametersonthestress-straincurveswasanalyzedtodeteminetheconstantsintheconstitutiveequations.2.Therulesofgraingrowthwereresearchedonthesolutionheattreatmentprocess.Themodelofgraingrowthwasestablishedbasedonthisexperiment.ThemathematicalmodeloftheAZ80magnesiumalloysmicrostructureevolutionwereestablishedbythehotcompressiontestsofAZ80magnesiumalloys.3.ThesubroutineofAZ80magnesiumalloysmicrostructureevolutionwascompiledbyusingthestrongsecondarydevelopmentfunctionoftheFEAsoftwareMSC.Marc.HotextrusionformingprocessoftheAZ80magnesiumalloyswassimulated.Theoptimizedprocessparameterwasbroughtforthbyanalyzingthedistributionoftemperature,effectivestrain,effectivestress,microstructureandresidualstrainforbilletunderdifferentdeformation.4.Basedonthehotcompressiontestsandthenumericalsimulation“experiments”,AZ80magnesiumalloywashotextrudedunderthedifferenttechnologicalparameters.Themicrostructureandmechanicalpropertiesofthealloybeforeandafterhotextrusionwereinvestigated.ThemicrostructureoftheAZ80alloywaseffectivelyrefinedafterhot-extrusion.Thegrainsbecomefinerwithincreasingextrusionratio.ThetensilestrengthoftheextrudedAZ80alloygotobviouslyenhancedwithanincreaseinextrusionratio.Theexperimentalresultswerebasicallyconsistentwiththenumericalsimulation.5.Theresearchshowedthatthetubeswithbettermicrostructureandmechanicalpropertiescouldbeobstainedbycontrolingthetemperatureofbilletandmoldpreheatingat390and360,Halfdieangle60°-70°,extrusionratio18.2.KeyWordsAZ80MagnesiumAlloy;MicrostructureEvolution;HotDeformationBehavior;FiniteSimulation;hotextrusion1111.1,21[1],[2-3]1.21.2.11997-201018%[4-5]1006045302020-40kg2000103kg1.2.23C2[6]3C19993C(PDA)[7]Encssoll60%Nokia20%CF788105mm×49mm×24mm35gPC/ABS0.5mmSolw199910MD(MZ-R90E-90)3C[8]1.2.3EUROCOPTER200-3002050ZM31967ZM3J6WP6ZM3WPll1370ZM3ZM4—1980ZM66()[9]MB5MB8MB15MB1540Ф20-Ф95mmMB8MB157mm-l8mmMB8MB15[10]SIG3315cmT-311.31.11.1(a)1.1(b)cε1.1(c)[11]Cellars[12]cε1.1(b)41.1Fig.1.1Typesofstress-straincurves1.1(b)1.1(b)cεpεsεZcεsε1.1(b)150cεZ1.41965MarcalMarcal(1967)Yamada(1968)Prandtl-Reuss-Mises7070Lee(1969)Hibbitt(1970)McMeeking(1975)(T.LU.L.Euler)[11]67080-1.5[13](MC)(CA)Chun[14]MCDing[15][16][17]5070Sellars[12]Jang[18]YadaC-Mn[19]MarcTC4Li[20][21]YadaAZ311.61.6.1AZ80AZ80171.6.2(1)AZ80(2)AZ80(3)(4)AZ80AZ80(5)FortranMSC.MarcAZ80(6)AZ8081.6.31.2Fig.1.2TechnicalRoute2AZ8092AZ80-[22]AZ80-AZ802.12.12.1AZ80Tab.2.1ChemicalcompositionofAZ80magnesiumalloyAlZnMnSiCuNiFeImpurityMg8.60.450.150.03≤0.01≤0.001≤0.005≤0.3Bal.102.22.2.1/GleebleThermecmasterThermecmasterGleebleGleeble-2000Gleeble-20002.12.2rεpε)/ln(220DDr=ε(2-1))/ln(0llp=ε(2-2)0D0lDl2.12.2Fig.2.1SchematicofexperimentFig.2.2ProcessofexperimentC-Strain2AZ8011)/(4200DlFlπσ=(2-3)F2.2.2Ф6mm×10mmGleeble-2000(+)2604100.001101−s10/s3min60%2.32.3.12.3.2[23]AZ801.5g25ml5ml10ml4%2.3.3,1000#—1500#—2000#90°15122.4AZ802.30.00.20.40.60.8050100150200250(a)0.001s-10.01s-10.1s-11s-110s-1Truestress/MPaTruestrain0.00.20.40.60.804080120160(b)Truestress/MPaTruestrain10s-11s-10.1s-10.01s-10.001s-10.00.20.40.60.804080120(c)Truestress/MPaTruestrain10s-11s-10.1s-10.01s-10.001s-10.00.20.40.60.8020406080100120(d)Truestress/MPaTruestrain10s-11s-10.1s-10.01s-10.001s-1(a)260(b)310(c)360(d)4102.3AZ80Fig.2.3Truestress-truestraincurvesforAZ80deformedatdifferenttempreture2.3AZ80[24]2.3AZ802AZ8013[25-26]2.5AZ802.5.1[27][28-35]Zener[36]Sellars[37]),T,(εεσσ&=(2-4)σMPaε&s-1ε14TKσε&[38]11nAσε=&(2-5)1A1n)exp(2βσεA=&(2-6)2AβSellarsTagartQTArrhenius[39])/exp()][sinh(RTQAn−=ασε&(2-7)AαnQJ/molR8.314J/mol·K-1TKZener-HollomonZ[]nARTQZ)sinh()exp(ασε==&(2-8)SellarsTegartQε&TArrheniusArrhenius[40])/exp()(RTQAF−=σε&(2-9))(σF,nFσσ=)(ασ0.8(2-10))exp()(σασnF=ασ1.2(2-11)nF)][sinh()(ασσ=(2-12))/exp(1RTQAn−=σε&ασ0.8(2-13)2AZ8015())/exp(exp2RTQnA−=σαε&ασ1.2(2-14))/exp()][sinh(RTQAn−=ασε&(2-15)ε&1s−QJ/molσMPanTKRR8.314J/mol·K-1AQ,A,nBariani[41]Beaudoin[42]Cheng[43]Laasraoui[44]Donahue[45]V-4Cr-4Ti2.5.2AZ80ArrheniusAZ80(2-15)(2-13)(2-14)RTQnA/lnlnln1−+=σε&(2-16)RTQnA/lnln2−+=σαε&(2-17)TRQAA,,,,21(2-16)(2-17)σεlnln∂∂=&n(2-18)σεα∂∂=&lnn(2-19)16(2-15)RTQnA−+=)]ln[sinh(lnlnασε&(2-20)εα&,,,,RnA(2-20){}()TddRnQ1)]ln[sinh(ασ=(2-21)Qnα(2-20))]ln[sinh(lnlnασεnRTQA−+=&(2-22)σεlnln∂∂=&nσεα∂∂=&ln1n{}()TddRnQ1)]ln[sinh(ασ=)]ln[sinh(lnlnασεnRTQA−+=&3.03.54.04.55.05.5-8-6-4-2024260310360410ln(strain-rate/s-1)ln(stress/MPa)3.03.54.04.55.05.5-8-6