剪应力状态下6061铝合金的力学性能及断裂行为-朱浩

22620126Vol.22No.6TheChineseJournalofNonferrousMetalsJun.20121004-0609(2012)06-1570-076061(050043)6061ABAQUS606160616061Johnson-Cook6061Johnson-CookTG146AMechanicalpropertiesandfracturebehaviorof6061aluminumalloyundershearstressstatesZHUHao,QIFang-juan,ZHANGYang(InstituteofMaterialsScienceandEngineering,ShijiazhuangTiedaoUniversity,Shijiazhuang050043,China)Abstract:Themechanicspropertiesandfracturebehaviorsof6061aluminumalloywereinvestigatedbythetensilesheartestsandin-situtensilesheartestswithtensileshearspecimendevised.TheFEMsoftwareABAQUScanbeusedtodescribethefracturebehaviorsof6061aluminumalloyundershearstressstates.Theresultsindicatethatwithincreasingtheshearstrainrates,theshearyieldstressandshearultimatestressof6061aluminumalloyremainconstantbasically,whiletheshearfracturestrainobviouslydecreases.Theshearstrainrateshavenoinfluenceonthefracturesurfaces.Alotofslipbandsparallelingtothetensiledirectionareproducedonthespecimens’surfaces.Thegrainboundariesof6061aluminumalloyaretheweakestarea,andthemicrocracksinitiateattheslipbandsandgrainboundariesparalleltothetensiledirectionundershearstress.Withincreasingtheshearstress,themicrocracksextendandcoalesce.Thespecimensfractureduetocoalescenceorshearingbetweenthemicrocracks.TheJohnson-Cookmodelcanbeusedtodescribethefracturebehaviorsof6061aluminumalloyundershearstressstates.Keywords:6061aluminumalloy;tensileshear;in-situtensileshear;fracturebehavior;Johnson-Cookmodel[1−3](211022)(E2012210001);(933005)(ZD2010209)2011-05-192012-01-050311-87935086E-mail:[e-mail]22660611571[4−7][8]6061606111.1Al-Mg-Si-Cu6061(T6)274.8MPa297.9MPa1116061Table1Compositionsofextrusion6061aluminumalloy(massfraction,%)SiMgFeZnCuMnCr0.691.020.430.200.260.150.2016061Fig.1Microstructureofextrusion6061aluminumalloy1.2[9−11]2(a)~(c)2(mm)Fig.2Schematicdiagramofseveralkindsofshearspecimens(mm):(a)Isoipescuspecimen;(b)Cupspecimen;(c)Punchspecimen;(d)Tensileshearspecimen;(e)In-situtensileshearspecimen2012615722(d)2(e)CKX−2AJ1.32(d)SHIMADZUAG−8TA130120360500mm/min0.010.331.334.005.56s−12(e)SEM−52022.1(τ)(γ)331.33s−16061Mg2Si[12]3Fig.3Curvesofshearstressstrainunderdifferentshearstrainrates0.33s−11.33s−11.33s−160616061[5,13]44Fig.4Effectofshearfracturestrainonshearstrainrates226606115734[13](f)05.0f4.0(1)55[14](σm/σe)(Equivalentplasticstrain,PEEQ)σm5Fig.5Tensileshearfracturesurfacesmorphologiesofdifferentshearstrainrates:(a)=0.01s−1;(b)=5.56s−1002.26()165.21MPa6(a)225.54MPa6(b)225.54MPa[15]165.21MPa400μm6(c)15°0()7(a)0.1(0)2.3ABAQUSσm/σe(σmσe)Johnson-CookJohnsonCook1983[16−18]])(1[ln1)(*0mnTCBA(2)201261574Tm)/()(rmr*TTTTT0Tr6Fig.6Surfacesobservationofin-situtensileshearspecimen:(a)165.21MPa;(b)225.54MPa;(c)165.21MPaJohnson-Cook*50em321f11)exp(4TDDDDD(3)ABnCmD1D2D3D4D58(C3D8R)7(a)7(b)A=250MPaB=265.94MPan=0.32C=0m=0D1=0.299D2=1.4965D3=3.32D4=D5=00.01s−1Mises87(a)0.14mm0.17Fig.7Distributionsofstresstriaxiality,normalstressandshearstress:(a)Distributionofstresstriaxiality;(b)Distributionofnormalstressandshearstress226606115757(b)8Johnson-Cook0.01s−180.01s−1MisersFig.8Curveofshearstressshearstrainundershearstrainrateof0.01s−1andMisersnephogram:(a)Curvesofshearstressshearstrainundershearstrainrateof0.01s−1;(b)165.21MPa;(c)225.54MPa;(d)165.21MPaMises8Johnson-Cook6061Johnson-Cook606131)2)606160613)60614)6061Johnson-CookREFERENCES[1]PIKETTAK,PYTTELT,PAYENF.Failurepredictionforadvancedcrashworthinessoftransportationvehicles[J].InternationalJournalofImpactEngineering,2004,30:853−872.[2]HOUSJ,LIQ,LONGSY,YANGXJ,LIW.Multiobjectiveoptimizationofmulti-cellsectionsforthecrashworthinessdesign[J].InternationalJournalofImpactEngineering,2008,35:1355−1367.[3]JOEMKP,JUNGKS.Amethodforprogressivestructuralcrashworthinessanalysisundercollisionsandgrounding[J].Thin-WalledStructures,2007,45:15−23.[4]BATRARC,LEARMH.Adiabaticshearbandinginplanestraintensiledeformationsofthermoelastoviscoplasticmaterials201261576withfinitethermalwavespeed[J].InternationalJournalofPlasticity,2005,21:1521−1545.[5]WARRENTL,FORRESTALMJ.Effectofstrainhardeningandstrain-ratesensitivityonthepenetrationofaluminumtargetswithspherical-nosedrods[J].IntJSolidStructures,1998,35:3737−3753.[6]ZHUH,ZHUL,CHENJH,LÜD.Investigationoffracturemechanismof6063Alalloyunderdifferentstressstates[J].InternationalJournalofFracture,2007,146(3):159−172.[7],,,.6063[J].,2007,36(4):597−601.ZHUHao,ZHULiang,CHENJian-hong,LÜXian-feng.Thestudyofdeformationanddamagemechanismofaluminumalloy(6063)underdifferentstressstates[J].RareMetalMaterialsandEngineering,2007,36(4):597−601.[8]GUGong-yao,XIAYong,ZHOUQing.Onthefracturepossibilityofthin-walledtubesunderaxialcrushing[J].Thin-WalledStructure,2012,55:85−95.[9]YANGRQ,LISX,ZHANGZF.Cyclicdeformationanddynamiccompressivepropertiesofcopperbaristas[J].MaterialsScienceandEngineeringA,2007,466(1/2):207−217.[10]FLEURYE,HAJS.Smallpunchteststoestimatethemechanicalpropertiesofsteelsforsteampowerplant:.Mechanicalstrength[J].InternationalJournalofPressureVesselsandPiping,1998,75:699−706.[1