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20220102Vol.20No.2TheChineseJournalofNonferrousMetalsFeb.20101004-0609(2010)02-0171-06Mg-12Gd-3Y-0.6Zr1,21211(1.4100832.315103)XMg-12Gd-3Y-0.6Zr6µmMg5Gd1−xYx{0002}20.5%107.1%Mg-12Gd-3Y-0.6ZrTG146.2AEffectofdouble-extrusiononmicrostructureandmechanicalpropertiesofMg-12Gd-3Y-0.6ZralloyLIUChu-ming1,2,LIBing-feng1,WANGRong2,LIHui-zhong1,CHENZhi-yong1(1.SchoolofMaterialsScienceandEngineering,CentralSouthUniversity,Changsha410083,China;2.NingboBranch,OrdnanceScienceInstituteofChina,Ningbo315103,China)Abstract:Theeffectofdouble-extrusiononthemicrostructureandmechanicalpropertiesofMg-12Gd-3Y-0.6Zralloywasstudiedbyopticmicroscopy(OM),scanningelectronmicroscopy(SEM)andX-raydiffractometry(XRD).Theresultsshowthat,afterdouble-extrusion,thegrainsizeofthisalloyisrefinedto6µm,whichimprovesthestrengtheningeffectofthefinegrain.ThecoarseMg5Gd1−xYxphaseincreases,resultinginthedecreasesofsolutionstrengtheningeffect.Theweakeningof{0002}basalplanetexturedecreasesthestrengtheningeffectofthetexture.Underthecomprehensiveeffectofthethreefactors,thestrengthofthisalloydecreasesslightlyafterdouble-extrusion,whereastheelongationincreasesremarkablyto20.5%,whichisincreasedby107.1%comparedwiththatoftheas-once-extrudedalloy.Thefracturemechanismoftheas-once-extrudedalloyiscompoundfracturecleavagefracture,andthatoftheas-double-extrudedalloyistoughnessandfracture.Keywords:Mg-12Gd-3Y-0.6Zralloy;microstructure;double-extrusion;mechanicalproperties;texture[1]Mg-Gd-Y-Zr[2−3]ANYANWU[4−5]Mg-Gd-Y-ZrWE54A2009-02-032009-05-070731-88877502E-mail:cmliu@mail.csu.edu.cn20102172HE[6]YANG[7]300MPaT5400MPa[8−9]Mg-9Gd-4Y-0.6ZrT5370MPa5%Mg-ZnAl-LiTi-Al[10−12]AZ9110µm3507.310−5s−1512%[13]Mg-Gd-Y-Zr[14−16]Mg-Gd-Y-ZrMg-Gd-Y-ZrMg-12Gd-3Y-0.6Zr1Mg-12Gd-3Y-0.6Zr()(30.47%Gd)(31.72%Y)(30.16%Zr)CO2+SF6d180mm(53024h)d45mmd50mmd15mm11420GB/T2282002CSS−441002mm/min5g+100mL+5mL+10mLPOLYVARMETSirion200BrukerD8DiscoverX22.11Mg-12Gd-3Y-0.6Zr135µm(1(a))(1(b))6µm1Mg-12Gd-3Y-0.6ZrFig.1Opticalmicrostructuresofcross-sectionofMg-12Gd-3Y-0.6Zralloy:(a)As-once-extruded;(b)As-double-extruded2Mg-12Gd-3Y-0.6Zr2(a)Mg2Y3Gd2(2(b))Mg2Y3Gd2Mg5Gd1−xYx202Mg-12Gd-3Y-0.6Zr1732Mg-12Gd-3Y-0.6ZrSEMFig.2SEMimagesofMg-12Gd-3Y-0.6Zralloy:(a)As-once-extruded;(b)As-double-extruded2.23Mg-12Gd-3Y-0.6Zr{0002}3{0002}(ED)4.02(3(a))2.1954.4%(3(b)){0002}2.3Mg-12Gd-3Y-0.6Zr44368.8MPa324.8MPa9.9%326.9241.2MPa20.5%107.1%2.45Mg-12Gd-3Y-0.6ZrLevel:0.36,0.73,1.10,1.46,1.83,2.19,2.56,2.93,3.29,3.66,4.023Mg-12Gd-3Y-0.6Zr{0002}Fig.3{0002}polefiguresofMg-12Gd-3Y-0.6Zralloy:(a)As-once-extruded;(b)As-double-extruded4Mg-12Gd-3Y-0.6ZrFig.4MechanicalpropertiesofMg-12Gd-3Y-0.6Zralloy:(a)As-once-extruded;(b)As-double-extruded201021745(a)5(a)5(a)5(c)()5(c)}0110{}0110{−5(b)5(b)5Mg-12Gd-3Y-0.6ZrFig.5FracturemorphologiesofMg-12Gd-3Y-0.6Zralloy:(a),(c)As-once-extruded;(b)As-double-extruded3Mg-12Gd-3Y-0.6Zr135µm6µmHall-Petch2/10y−+=Kdσσ(1)σyσ0Kd(1)4[17]40%100µm10µm10µm6µmMg-Gd-Y-ZrGdYMg5Gd1−xYx(2(b))GdYMg-12Gd-3Y-0.6Zr[18−20]{0002}202Mg-12Gd-3Y-0.6Zr175Schmid(m)Schmidτc=σscosλcosφ=σsm(2)τcττcλφcosλcosφSchmid(2)λφ90˚SchmidτcσsCottrell-Petch[21]dmβµγττσ])([2c32/1c0rmdrm+(3)µγβτcσ0rdm3Mg-12Gd-3Y-0.6Zr20.5%41)Mg-12Gd-3Y-0.6Zr20.5%107.1%2)Mg-12Gd-3Y-0.6Zr6µmMg5Gd1−xYx{0002}3)Mg-12Gd-3Y-0.6ZrREFERENCES[1]MATUCHAKH.[M].,.:,1999.MATUCHAKH.Structureandpropertiesofnonferrousalloys[M].DINGDao-yun,transl.Beijing:SciencePress,1999.[2]MORDIKEBL.Creep-resistantmagnesiumalloys[J].MaterSciEngA,2002,324(1/2):103−112.[3],,,.[J].,2004,14(9):1443−1450.ZHANGXin-ming,PENGZhuo-kai,CHENJian-mei,DENGYun-lai.Heat-resistantmagnesiumalloysandtheirdevelopment[J].TheChineseJournalofNonferrousMetals,2004,14(9):1443−1450.[4]ANYANWUA,KAMADOS,KOJIMAY.AgingcharacteristicsandhightemperaturetensilepropertiesofMg-Gd-Y-Zralloys[J].MaterialsTransactions,2001,42(7):1206−1211.[5]ANYANWUA,KAMADOS,KOJIMAY.CreeppropertiesofMg-Gd-Y-Zralloys[J].MaterialsTransactions,2001,42(7):1212−1218.[6]HESM,ZENGXQ,PENGLM.MicrostructureandstrengtheningmechanismofhighstrengthMg-10Gd-2Y-0.5Zralloy[J].JournalofAlloysandCompounds,2007,427(1/2):316−323.[7]YANGZ,LIJP,GUOYC.PrecipitationprocessandeffectonmechanicalpropertiesofMg-9Gd-3Y-0.6Zn-0.5Zralloy[J].MaterSciEngA,2007,454/455:274−280.[8],,,,,.Mn,ZrMg-Gd-Y[J].,2005,15(6):917−922.PENGZhuo-kai,ZHANGXin-ming,CHENJian-mei,XIAOYang,JIANGHao,DENGZhen-zhen.EffectsofMn,ZronmicrostructureandpropertiesofMg-Gd-Yalloys[J].TheChineseJournalofNonferrousMetals,2005,15(6):917−922.[9],,,,,.Mg-Gd-Y-(Mn,Zr)[J].,2006,16(2):219−227.ZHANGXin-ming,CHENJian-mei,DENGYun-lai,XIAOYang,JIANGHao,DENGZhen-zhen.MicrostructuresandmechanicalpropertiesofMg-Gd-Y2(Mn,Zr)magnesiumalloys[J].TheChineseJournalofNonferrousMetals,2006,16(2):219−227.[10],,,,,.Mg-Zn-Zr-Re[J].:,2008,39(2):228−233.ZHANGZhen-dong,LIUChu-ming,CHANGYa-zhe,LI20102176Hui-zhong,WANGRong,ZHOUHai-tao.EffectofnumberofextrusiontimesonmicrostructureandpropertiesofMg-Zn-Zr-Realloys[J].JournalofCentralSouthUniversity:ScienceandTechnology,2008,39(2):228−233.[11],,,,.Al-Li[J].,1991,22(2):174−183.ZHANGXin-ming,SHIQi-nian,YINZ