简介：BondingofAl2O3tocuisperformeddirectlyusingTifoilattemperatureof1273K.Themicrostructureofthejointinterfaceisinuestigatedthroughscanningelectronmicroscope（SEM）,electron.probemicroanalysis（EPMA）andX-raydiffraction（XRD）.theeffectoftheinitialtifoilthicknessonthereactionlayerthicknessandthejointStrengthareinvestigated.

简介：Theobjectiveofthisstudyistoinvestigatetheinfluenceofaddingtinyamountofmixedrareearth(La,Ce)andSrtoAl-20Cu-5Si-2Nifillermetal,byanalyzingthemicrostructure,wettabilityandmechanicalpropertiesofbrazedjoints.Theresultsshowthawiththeadditionofmixedrareearth(La,Ce)intoAl-20Cu-5Si-2Nialloy,theα-AlsolidsolutionaswellasCuAl_2(Ni)intermetalliccompoundphasesignificantlyreduced,whilemoreAl-SieutecticphaseandAl-Si-Cuternaryeutecticphasewereproduced.Andasmixedrareearth(La,Ce)addedin,thewettabilityofAl-20Cu-5Si-2Nifillermetaldecreased,whiletheshearstrengthofthebrazedjointsincreased.TheadditionofMinorSrmodificatedAl-20Cu-5Si-2Nifillermetal,furtherreducedtheCuAl_2(Ni)intermetalliccompoundphase,whichwaspartiallyreplacedAl-Si-Cuternaryeutecticphase.Asaresult,thetensilestrengthaswellasthewettabilityofthefillermetalwasimproved.

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简介：CreeppropertyofsolderalloysisoneoftheimportantfactorstoaffectthereliabilityofsolderedjointsinSMT(surfacemounttechnology).Particle-enhancementisawaytoimprovethepropertiesofsolderalloysandhascausedmuchmoreattentionthanbefore.Temperaturesappliedtosolderedjointsareoneoftheprimaryfactorsofaffectingcreeppropertiesofparticleenhancementcompositesolderedjoints.Inthispapersingleshearlapcreepspecimenswitha1mm2cross-sectionalareawerefabricatedusingCuparticleenhancement63Sn37Pbbasedcompositesolderedjointsand63Sn37Pbeutecticsolderedjointstoexaminetheinfluenceoftemperatureoncreepbehaviorofsolderedjoints.ResultsindicatedthatthecreepresistanceofsolderedjointsofCuparticleenhancement63Sn37Pbbasedcompositesolderedjointwasgenerallysuperiortothatoftheconventional63Sn37Pbsolderedjoint.Atthesametime,creeprupturelifeofthecompositesolderedjointwasdeclinedwithincreasingtemperatureanddropfasterthanthatoftheconventional63Sn37Pbeutecticsolderedjoint.

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简介：Forthedevelopmentofalow-melting-pointfillermetalforbrazingaluminumalloys,aseriesofAl-Si-Cu-(Ni,Sn,Zn)fillermetalshavebeenstudied.Throughdifferentialthermalanalysis(DTA),themeltingtemperaturesofsuchAl-Si-Cu-(Ni,Sn,Zn)fillermetalsweredetermined.Theresultsshowthattheadditionof3wt.%-5wt.%SnintotheAl-6Si-15Cufillermetalcausesitssolidustemperaturetodecreasebyabout12℃.ThefillermetalwiththecompositionAl-6Si-l5Cu-2Niisproposed,whichpossessesameltingtemperaturerangeof512℃to520℃andamicrostructarethatincludesanAl-Cueutecticphases,Al-Si-Cueutecticphases,siliconparticlesandCu_2Al,AlNi_3,Al_7Cu_4NiandAl_3Ni_2intermetalliccompounds.Anadditionof5wt.%-7wt.%ZnintosuchAl-Si-Cufillermetalscausetheirsolidustemperaturestodropfurthertoavaluelowerthan498℃.MetallographicobservationsindicatethattheadditionofZnintotheAl-Si-CufillermetalinhibitstheformationoftheAl-Si,Al-CuandAl-Si-Cueutecticphases.TheremainingphasesareaAl_2Cuintermetalliecompound,anα-Alsolidsolutionandsiliconparticles.

简介：Cracksmayeasilyoccurinthefusionweldbetweenvanadiumalloysandstainlesssteelduetothebrittleintermetallicsandweldingstress.Thehighvacuumelectronbeambraze-weldinghasbeensuccessfullyusedtojoinvanadiumalloy(V-5Cr-5Ti)tostainlesssteel(HR-2)withelectroplatedCuandAgcoating.Toinvestigatetheeffectsofelectroplatedcoatingontheweldability,thejointappearance,themicrostructureandthemechanicalpropertiesofthejointshavebeenthoroughlyanalyzed.Theresultsshowthatthejointsurfaceconfigurationwasgoodandrootreinforcementwasfullandsmooth.Areactionzone(RZ)wasgainedontheinterfacebetweentheVSCrSTialloyandHR-2stainlesssteelbasemetals.Thewidthofreactionzoneatthetopofthejointwasupto0.65mm,widerthanthatinthebottomofthejoint(0.46mm).Thereactionzoneconsistedofconsiderablysmallerdendriticstructureswithanaveragegrainsizeoflessthan10μm.ElementAgandCualmostenrichedtheinterfacebetweenV-5Cr-5TialloysubstrateandRZ,servingasaphysicalbarrierwhichdecreasesoravoidstheformationofintermetallics.Themaximumtensilestrengthofvanadiumalloy/stainlesssteeldissimilaralloyjointwasmorethan300MPa.Thejointwasdefectsfree.

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简介：SolderingofLD31aluminumalloysusingSn-PbsolderpasteafterelectricbrushplatingNiandCucoatingswasnvestigated.ThetechnologyofelectricbrushplatingNiandCuwasstudiedandplatingsolutionwasdeveloped.Themicrostructureofthecoatings,solderedjointandfracturefacewereanalyzedusingopticmicroscopy,SEMandEDX.Theshearstrengthofsolderedjointcouldreachashighas26.83MPa.Theresultsshowedthatreliablesolderedjointcouldbeobtainedat230℃,theadhesionofcoatingsandLD31aluminumalloysubstratewashighenoughtobearthethermalprocessinthesoldering.

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简介：TheCu/Sn-3.OAg-0.5Cu/Cubuttingsolderjointswerefabricatedtoinvestigatetheevolutionoftheinterfacialintermetalliccompound(IMC)andthedegradationofthetensilestrengthofsolderjointsundertheeffectofelectromigration(EM)andagingprocesses.Scanningelectronmicroscopy(SEM)resultsindicatedthattheCu_6Sn_5interfacialIMCpresentedobviousasymmetricalgrowthwiththeincreaseofEMtimeundercurrentdensityof1.78×10~4A/cm~2at100℃,andthegrowthofanodicIMCpresentedaparabolicrelationshipwithtimewhilethecathodicIMCgotthinnergradually.However,asforagingsamplesat100℃withoutcurrentstressing,theCu_6Sn_5IMCpresentedasymmetricalgrowthwithaslowerratethantheanodicIMCofEMsamples.Thetensileresultsindicatedthatthetensilestrengthofthesolderjointsundercurrentstressdeclinedmoredrasticwithtimethantheagingsamples,andthefracturemodetransformedfromductilefracturetobrittlefracturequicklywhilethefracturemodeofagingsamplestransformedfromcup-coneshapedfracturetomicroporousgatheringfractureinaslowway.

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简介：ThevacuuminductionbrazingofSiCparticulatereinforcedLY12alloymatrixcompositeusingAl-28Cu-5Si-2Mgfillermetalhasbeencarriedout.Themicrographofthejointinterfacewasobservedbyscanningelectronmicroscopy.Thejointstrengthwasdeterminedbysheartests.Theresultsshowthatbrazingtemperature,holdingtime,SiCparticlevolumepercentageandpostheattreatmentinfluencejointstrength.SiCparticleshappeninthebrazingseamandthedistributionofSiCparticlesinthejointisnotuniform.Particle-poorzonesinthejointexistnearthebasemetal,andparticleconcentratezonesexistinthecenterofthebrazingseam.Inaddition,thefailureofthecompositeispredominantlyinitiatedbytherootingofSiCparticleinthebrazingseamandthemicro-crackexpandedalongthebrazingseamwithlowenergy.

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简介：本文结合生产实践,简要分析提出了CO2气体保护焊目前所存在的缺陷与问题,并提出了相应的解决方法与CO2气体保护焊的发展趋势。