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MAINTOPICS，ABSTRACTS＆KEYWORDS2011，Vol．32，No．12
Throughcomparingthesimulationresultsandexperimentalmeas-urements，thepredictionaccuracyofthedevelopedthermo-elas-tic-plasticFEMbasedonQuickWelderwasverified．Mean-while，theinfluenceofweldingsequenceontheresidualstress
distributionwasclarifiedusingnumericalsimulationmethod．Theresultsshowthatbothtransverseresidualstressandlongitudinalresidualstressweresignificantlyaffectedbydepositionsequence．Thedepositionsequencenotonlylargelychangesthepeakvaluesofresidualstress，butalsoalterstheshapeofresidualstressdis-tribution．
Keywords：numericalsimulation；non-linearanalysis；weldingresidualstress；weldingsequence
NanoindentationmeasurementofSn-Cu-NijointWANG
Jianxin，LAIZhongmin，SUNDandan（ProvinceKeyLabofAd-vancedWeldingTechnology，JiangsuUniversityofScienceandTechnology，Zhenjiang212003，China）．p59－62
Abstract：Inordertostudytheeffectofintermetalliccompoundonmechanicalpropertiesofjoint，theelasticmodulusandhardnessofintermetalliccompoundswereanalyzedbynanoindentationmethod，andthecreepstrainratesensitivityofsoldermatrixwasobtainedbyMayo-Nixmethod．Fromthephysi-calanalysisofnanoindentationcurves，theelasticmoduluof（Cu，Ni）6Sn5inSn-Cu-Nijointsis113．2GPa±4．8GPa，
whilethehardnessis5．59GPa±0．32GPa．Itisfoundthatin-termetalliccompoundsarethekeyfactorsinthereliabilityoflead-freejoints，duetothebigcontrastsbetweenmechanicalpropertiesofintermetalliccompoundsandsoldermatrix．ThecreepstrainratesensitivitiesofSn-Cu-Ni，Sn-Cu-Ni-0．05Ceand
Sn-Pbsoldermatrixare0．1286，0．1248，and0．1832，andthecreepstressexponentsare7．7760，8．0128，and5．4585，re-spectively，whichindicatetheimprovementincreepresistanceofSn-Cu-NijointsduetoCeaddition．Keywords：lead-freesolder；nanoindentation；elasticmodulu；creepstrainratesensitivity
InterfacialmicrostructureofsinteringcompositesofPCBN
ZHANGBin，grains-graphiteparticles-CuSnTialloy
DINGWenfeng，XUJiuhua，CHENZhenzhen，SUHonghua，FUYucan（CollegeofMechanicalandElectricalEngineering，NanjingUniversityofAeronauticsandAstronautics，Nanjing
69210016，China）．p63－65，
Abstract：SinteringexperimentsofCu-Sn-Tialloy，poly-crystallinecubicboronnitride（PCBN）abrasivegrainsandgraphiteparticleswerecarriedoutattheheatingtemperatureof920℃withthedwelltimeof30min．Thestrengthofsinteringbulkswasmeasuredbymeansofthethree-pointbendingexperi-ments．Theinterfacialmicrostructureandthephasesofthesinte-ringbulkswerecharacterizedusingscanningelectronmicroscope（SEM），energydispersionspectrometer（EDS）andX-raydif-fraction（XRD）．Theresultsrevealthatinthecaseofthegraph-itecontentof5～15wt%，thebendingstrengthofthecompositebulksisabove91MPa，whichismuchhigherthanthatofthebulkstrengthofthevitrifiedgrindingwheels．Theelementaldif-fusionbehaviorhastakenplaceacrossthejoininginterfacebe-tweenPCBNgrainsandCu-Sn-Tialloyinthesinteringprocess．
Thecompoundswereformed，therefore，thePCBNgrainswerebondedfirmly．Undersuchcondition，thebreakageofthePCBNgrainshasplayedthemostimportantroleinthefractureofthecompositebulks．Inparticular，thebreakagemodeofthePCBN
grainsistheintergranularfracture．
Keywords：PCBNabrasivegrains；Cu-Sn-Tialloy；ben-dingstrength；interfacialmicrostructure
Finiteelementanalysisoftemperaturefieldduringkeyhole-plasmaarcweldingusingSYSWELDsoftwareHU
112
Qingxian，WANGYanhui，YAOQingjun，WANGShunyao1（1．ProvincialKeyLabofAdvancedWeldingTechnology，Jian-gsuUniversityofScienceandTechnology，Zhenjiang212003，China；2．JiangsuProvinceSpecialEquipmentSafetySupervi-sionInspectionInstitute，YangzhouBranch，Yangzhou225003，China）．p66－69
Abstract：Consideringtheweldgeometriccharactersofkeyholeplasmaarcwelding（K-PAW），asuitableandadaptive
combinedheatsourcefornumericalsimulationisdeveloped，i．e．atthetransversecross-sectionandalongtheworkpiecethick-ellipsoidalvolumetricheatsourceactsnessdirection，thedouble-atupperpartoftheworkpiecewhilealinearly-increasedpeak
valueofheatfluxingaussiancylindermodeexertsatlowerpartoftheworkpiece．Basedonthedevelopedadaptivecombinedheatsourcemodel，theweldingtemperaturefieldof6mmthick-nessstainlesssteelissimulatedbySYSWELD．Thepredictedweldgeometryandfusionlinelocusatcross-sectionareingood
agreementwiththeexperimentalmeasurement．Thisdemonstratesthesuitabilityofthecombinedvolumetricheatsourcemode．
Keywords：keyholeplasmaarcwelding；temperaturefield；combinedvolumetricheatsource；finiteelementanalysisStudyonultrasonicstirhybridweldingofaluminumalloyHEDiqiu，LIJian，LIDonghui，LIANGJianzhang（StateKeyLaboratoryofHigh-performanceComplexManufacturing，Central
SouthUniversity，Changsha410083，China）．p70－72，108
Abstract：Frictionstirwelding（FSW）ofaluminumalloyusuallyresultsinaspecial"funnelshaped"temperaturefield，whichmakesobviousdifferenceofmicrostructurepropertiesinthedirectionofweldseams．Inordertogetbetterpropertiesofweldedjoints，ultrasonicstirhybridweldingtechnologyhasbeen
whichconcentratestheultrasonicener-putforwardinthispaper，
gyindeepweldseamsthroughthestirringpin．Thicknessof2．5mm2219aluminumalloysheetshasbeenadoptedandweldedbythetwotechnologiesmentionedaboveinthisexperiment，micro-structureandmechanicalpropertiesofweldareanalyzedandcomparedaswell．Resultshowsthattheweldjointsof2219alu-minumweldedbythetwotechnologiesarebothwithgoodappear-anceanddefect-freeintheinner，andultrasonicstirhybrid
weldingobviouslyhasbettermechanicalproperties．
Keywords：ultrasonicstirhybridwelding；frictionstirwelding；2219aluminumalloy
EffectofNdadditiononmicrostructureandmechanicalpropertyofSn3．8Ag0．7CusolderjointGAOLili，XUESongbai，WANGBo（CollegeofMaterialsScienceandTechnolo-gy，NanjingUniversityofAeronauticsandAstronautics，Nanjing210016，China）．p73－76
Abstract：TheeffectsofNdaddition（0，0．05，0.5wt%）onthemicrostructureandshearstrengthofSACsolderjointun-deras-reflowedand150℃isothermal-agingprocesswereinves-tigated．ExperimentalresultsshowedthatNdadditioncanobvi-ouslyimprovetheshearstrengthandmicrostructureoftheSACsolderjoints．ThegrowthrateoftheSAC/Cuinterfaciallayeras