FeCoCrMoCBY大块非晶合金的变温晶化行为及力学性能

南昌航空大学硕士学位论文Fe-Co-Cr-Mo-C-B-Y大块非晶合金的变温晶化行为及力学性能姓名：魏丹丹申请学位级别：硕士专业：材料学指导教师：艾云龙;陈庆军20080501IIIFe41Co7Cr15Mo14Y2C15B6(DSC)X-(XRD)(SEM)DSC(Tg)(Tx)(Tp1Tp2)KissingerOzawaFeTgTxTp1Tp2EgExEp1Ep2KissingerOzawa475oC15minFe23B6Cr23C6570oC15minFe23B6Cr23C6Fe3Ba-Fe570oC15min1153Kg/mm26.1404MPa·m1/2426.55MPa2573.4MPabcIVABSTRACTInthisdissertation,Fe41Co7Cr15Mo14C15B6Y2bulkamorphousalloywithhighglassformingabilityandhighstrengthhasbeeninvestigated.ThisBMGispreparedwithindustrialpurerawmaterialsbythemagnetic-controllingW-electrodearcfurnace.Thenon-isothermalcrystallizationkinetics,crystallizationbehaviors,mechanicalpropertiesandtheeffectofthepre-treatmentonthecrystallizationbehaviorsandmechanicalpropertiesofthisBMGaresystematicallystudiedmainlybyemployingthedifferentialscanningcalorimeter(DSC),X-raydiffraction(XRD)andscanningelectronmicroscope(SEM).ThecontinousheatingDSCresultsindicatethatthisbulkamorphousalloyshowstwo-stageamorphous-to-crystallinetransformation.Thedynamiceffectofthethermalstabilityparametershasbeenstudiedforthecontinuousheatingprocess,whichshowsthatthecharacteristictemperaturesincludingglasstransitiontemperatureTg,onsetcrystallizationtemperatureTxandpeakcrystallizationtemperatureTp1Tp2dependontheheatingrates.Thefittedresultsindicatethatthisdependenceobeysafirstorderexponentialdecayrelation.TheactivationenergiesEg,Ex,Ep1,Ep2correspondingtocharacteristictemperaturesTg,Tx,Tp1,Tp2havebeenobtainedfromKissingerandOzawaequationsrespectively.TheresultsindicatethatthevaluesofactivationenergyareveryclosetoeachotherbyusingthesetwomethodsandtheactivationenergiesobtainedbyKissingermethodishigherthanthatobtainedbyOzawamethod.Meanwhilethethermalstabilityofthisbulkamorphousalloywasveryhigh.Annealingtemperaturehassignificanteffectsoncrystallizationbehaviors,structureandmechanicalpropertiesofamorphousalloys.Theeffectoftherelaxationandpre-annealingtreatmentonthecrystallizationbehaviorsissystematicallyinvestigatedinthispaper.Theresultsshowthatwiththeimprovementofannealingtemperature,thethermalstabilityofsamplesisfalling,becausepre-annealingtreatmentletsthisbulkamorphousalloyproducecrystalswhichcanbringitformingmorecrystalsinthesubsequentheatingprocess;whereasthethermalstabilityisrisingwhenannealingtemperatureis570oC,becausetheremnantamporphousphaseFe23B6Cr23C6andnewcrystallinephaseFe3Ba-Fearebeginningtodevitrification.Mechanicalexperimentsshowthatthemicrohardness,fracturetoughness,bendingfracturestrengthandcompressivefracturestrengthofthisBMGare1153Kg/mm2,V6.1404MPa·m1/2,426.55MPaand2573.4MPa,respectively.Withtheimprovementofannealingtemperature,thecompressivefracturestrengthofthesamplesisrisingatbeginningandthendropping.Inthecompressivefracturemorphologies,wecanfindthatthenumberofshearbandisdecreasing,thedimensionisenhancingand“acicularcrystal”isappearingwiththeimprovementofannealingtemperaturewhichindicatethisBMGiscrystallizationgradually.ObservingfracturemorphologiesofthisBMGusingScanningElectronMicroscope(SEM),itisconcludedthatthebendingfractureofFe41Co7Cr15Mo14C15B6Y2bulkamorphousalloyisbrittlefractureandpossessesmicroscopicaltoughnessmechanism.Thecompressivefractureofas-castsampleandpre-annealingtreatmentsamplesarealsobrittlefracture.Keywords:Fe-basedbulkamorphousalloy,non-isothermalcrystallizationkinetics,thermalstability,pre-treatment,mechanicalproperty67()1111.12050[1][2][3][4][2]Fe41Co7Cr15Mo14C15B6Y23500MPa[5]35004000MPa[2][6][7][2]1995Fe-(Al,Ga)-(P,C,B,Si)Fe-(Al,Ga)-(P,C,B,Si)(Nd,Pr)-Fe-(Al,Si)(Fe,Co)-(Zr,Hf,Nb,Ta)-B(Fe,Co)-Ln-BFe-(Cr,Mo,W)-C-B5[8]JsHc12[9]GFA[10][11]GlassFormingAbility,GFARc∆T(=Tx-Tg)TxTg)1012Pa·s[12][12][13][14][15][16][12]13[3]Fe-Co-Cr-Mo-C-B-YFe1.2Fe1.2.1FeFe[17-18](≥104K/s)[19]GFA10mmZrCu1988A.InoueRc0.1K/sK/s(1)(2)12%(3)[20-21]1995Inoue[22]Fe-(Al,Ga)-(P,C,B,Si,Ge)Nd-Fe-A11995Inoue[23]Fe(Fe,Co,Ni)-(Zr,Nb,Ta,Mo,W)-B6mmFe(Fe,Co)-(Zr,Hf,Nb)-B[24]Fe-Co-Ln-BFe-(Nb,Mo)-(AI,Ga)-(P,B,C)[25]2001Shen[26]Fe-(Co,Sb,Cr,Mo,Ga)-(P,B,C)Fe40Ni40P14B64mm1mmFe-(Cr,Mn)-(Mo,Co)-(P,C,B)-(Er,Y)FeLu[27]14(Fe44.3Cr10Mo12.8Mn11.2C15.8B5.9)98.5Y1.5(Fe44.3Cr5Co5Mo12.8Mn11.2C15.8B5.9)98.5Y1.52006Chen[28]16mmFe41Co7Cr15Mo14Y2C15B61-1[22]1-1Table1-1ThetypicalFe-basedbulkamorphousalloysandtheirdiscoveringtimeFe-(Al,Ca)-(P,C,B,Si,Ce)1995Fe-(Nb,Mo)-(Al,Ga)-(P,B,Si)1995Fe-(Zr,Hf,Nb)-B1996Fe-Co-La-B1998Fe-(Nb,Cr,Mo)-(C,B)1999Fe-(Nb,Cr,Mo)-(P,B)1999Fe-Ga-(P,B)2000Fe-(Co,Sb,Cr,Mo,Ga)-(P,B,C)Fe-(Cr,Mn)-(Mo,Co)-(P,C,B)-(Er,Y)20012004ZPLu[29]GFA(1)(2)GFA[28]Fe58Co10Zr10Mo5W2B15NiNiFe58Co10-xNixZr10Mo5W2B15x=3456at%XRDDSC1-2[28]151-2Fe58Co10-xNixZr10Mo5W2B15XRDDSCTable1-2TheXRDandDSCparametersofFe58Co10-xNixZr10Mo5W2B15alloysTg/KTx/KTx/KTm/KTrgFe58Co7Ni3Zr10Mo5W2B158809426214450.5812Fe58Co6Ni4Zr10Mo5W2B158879577014400.5902Fe58Co5Ni5Zr10Mo5W2B158579297214290.5664Fe58Co4Ni6Zr10Mo5W2B158729406814270.57711-2Ni=4at%Fe58Co6Ni4Zr10Mo5W2B15TgTxTxTrg887K957K70K0.5902TgTxTrgFe58Co6Ni4Zr10Mo5W2B15NiFeNi()[30][30]()1976103000t500t16[31]Johnson[31]1.2.21.2.2.1[32]1.2.2.2B2O3[33]1.2.2.31.2.2.4171.2.2.51.2.2.6Tx(TgTx)TxTx90K10K[34]181.31.3.1[35][36