简介：Theelevatedtemperaturetensileexperimentshavebeencarriedoutonthemagnesiumalloyandresultsindicatethatthemagnesiumalloyhasexcellentsuperplasticproperty.Gleebe-1500testingmachinewasusedinthediffusionbondingexperimentonthesuperplasticmagnesiumalloy.Then,theshearstrengthofthejointsunderdifferentconditionsisobtainedthroughsheartestingandtheoptimumprocessingparametersforthediffusionbondingareachieved.Bymetallurgicalmicroscopeandscanningelectronmicroscope(SEM),itisrevealedthatthemicromechanismofdiffusionbondingistheslideofgrainboundariescausedbythegrowthofgrainsandatomdiffusionofthesuperplasticmagnesiumalloy.

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简介：Automaticgastungstenarc(GTA)weldinghasbeenutilizedtoconnectAZ31magnesiumalloybuttedplateswithAZ61andAZ61-1.0Sbfillerwire.ContrastedtoAZ61fillerwire,theAZ61-1.0Sbfillerwireholdsacomponentof1wt%antimony(Sb).Inthepresentwork,properweldingtechnologyparaneterswereexplored.AndthemicrostructureandperformanceofweldedjointswereanalyzedtoresearchtheinfluenceofSbonmagnesiumalloyweldedjoint.Observedfromthemicrostructureofweldedjoint,additionofSbhasrefinedcrystalgrainsandchangedthepatternofeutecticinbeadandheataffectedzone(HAZ)adjacenttobeadfromdiscontinuousreticulartograininessstructure,whichstrengthentheweaknessofjoint.Inaddition,becauseoftheanchoringactionofMg3Sb2phasesaswellashamperingactiontocrystalboundaryslip,theperformanceofjointweldedbyAZ61-1.0Sbfillerwirehasbeenimproved.

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简介：ThefatiguepropertyofAZ31magnesiumalloyanditsTIGweldedjointswereinvestigated.Theultrasonicpeeningtreatment(UPT)wasusedtoimprovethefatiguepropertyoftheTIGweldedjoints,whichwastreatedattheweldtoebytheUPTprocess.ThetestresultsshowthatthefatiguestrengthofthebasemetalofAZ31magnesiumalloysis57.8MPa,andthoseofthefilletjointandthetransversecrossjointarerespectively20.0MPaand17.2MPaat2×106cycles.ThefatiguestrengthsoftwokindsofweldedjointstreatedbytheUPTarerespectively30.3MPaand24.7MPa,whichhavebeenimprovedby51.5%and43.6%,respectively.Thefatiguelifeofthefilletjointspecimensisprolongedbyabout2.74timesandthefatiguelifeofthetransversecrossjointspecimensisprolongedbyabout1.05timeswhenthestressrangeisat40.0MPa.

简介：Thefatiguepropertiesoffrictionstirwelded(FSW)buttjointandbasemetalofMB8magnesiumalloywereinvestigated.ThecomparativefatiguetestswerecarriedoutusingEHF-EM200K2-070-1AfatiguetestingmachineforbothFSWbuttjointandbasemetalspecimens.ThefatiguefractureswereobservedandanalyzedusingascanningelectronmicroscopeofJSM-6063LAtype.TheexperimentalresultsshowthatthefatigueperformanceoftheFSWbuttjointofMB8magnesiumalloyissharplydecreased.Theconditionalfatiguelimit(2×10~6)ofbasemetalandweldedbuttjointisabout77.44MPaand49.91MPa,respectively.Theconditionalfatiguelimit(2×10~6)oftheweldedbuttjointis64.45%ofthatofbasemetal.Themainreasonsarethattheweldingcanleadtostressconcentrationintheflasharea,tensileweldingresidualstressintheweldedjoint(Theresidualstressvaluewas30.5MPa),aswellasthegrainsizeisnotuniformintheheat-affectedzone.Thecleavagestepsorquasi-cleavagepatternspresentonthefatiguefracturesurface,thefracturetypeoftheFSWbuttjointbelongstoabrittlefracture.

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简介：LaserweldingwithfillerwireofAZ31magnesiumalloysisinvestigatedusingaCO2laserexperimentalsystem.Theeffectofthreedifferentfillerwiresonthejointpropertiesisresearched.Theresultsshowthattheweldappearancecanbeeffectivelyimprovedwhenusinglaserweldingwithfillerwire.ThemicrohardnessandtensilestrengthofjointsarealmostthesameasthoseofthebasemetalwhenERAZ31orERAZ61wireisadopted.However,whenthefillerwireofER5356aluminumalloyisused,themechanicalpropertiesofjointsbecomeworse.ForERAZ31andERAZ61fillerwires,themicrostructureofweldzoneshowssmalldendritegrains.Incomparison,forER5356fillerwire,theweldshowsastructureofsnowydendritesandmanyintermetalliccompoundsandeutecticphasesdistributeinthedendrites.Theseintermetallicconstituentswithlowmeltingpointincreasethetendencyofhotcrackandresultinfragilejointproperties.Therefore,ERAZ31andERAZ61wirearemoresuitablefillermaterialthanER5356forCO2laserweldingofAZ31magnesiumalloys.

简介：Microstructuresandmechanicalpropertiesoftransientliquidphase(TLP)bondedmagnesiummetalmatrixcomposite(MMC)jointsusingcopperinterlayerhavebeeninvestigated.Withanincreaseofbondingtimesfrom5minto50minatbondingtemperatureof510℃,theaverageconcentrationofcopperinthebondedzonedecreased,themicrostructureinthezonechangedfromCu,α-MgandCuMg2toα-Mg,CuMg2andTiC,andmechanicalpropertiesofthejointincreased.Theshearstrengthofthejointbondedat510℃for50minreached64MPaduetothemetallurgicalbondingofthejointandimprovingitshomogeneityofcompositionandmicrostructure.ItisfavorabletoincreasethebondingtimeforimprovingmechanicalpropertiesofTLPbondedmagnesiumMMCjoint.

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