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简介：Inthispaper,anumericalinvestigationaboutthemetaltransferofGMAWisinvestigatedbasedonthephasefieldmodel.Bedifferentofmostpublishedwork,wetakethethermocapillaryeffectandmixtureenergyintotheprocessofphasetransferandinterfacechangewhichisdifferentfromvolumeoffluid(VOF)method.Wediscretizethewholemodelwithacontinuousfiniteelementmethodandwealsoapplyapenaltyformulationtothecontinuityconditionenhancingthestabilityofthepressure.MetaltransferofGMAWwithconstantandpulsecurrentiscomputedasnumericalexampleswhichagreeswellwiththedataofhigh-speedphotography.Theresultshowsthatthecomputingprocessofthephasefieldmodelisstabilityandithasahigherprecisioninpredictingthediameterofdroplet.

简介：Inthiswork,thewettability,agingandshearpropertiesofanewtypeoflead-freesolderpasteSn-07Ag-05Cu+BiNi(SACBN07)wasinvestigatedbyconductingaseriesofcomparisonexperimentswithSAC305andSAC0307solderpaste.TheresultsshowthatwettabilityofSACBN07isalmostequaltoSAC305,andbetterthanthatofSAC0307solderpaste.Thethicknessofintermetalliccompound(IMC)layerinSACBN07/Cuislowerthanthatofothertwotypesofsolderjointafteraging.AndCu_3SnlayerofSACBN07/CuisthinnerthanthatofSAC305andSAC0307.Inaddition,theSACBN07solderjointsperformthebestshearstrengthamongthesethreetypesofsolderpastes.

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简介：Fromtheviewpointofweldingmechanics,twonewweldingmethods-weldingwithtrailingpeeningandweldingwithtrailingimpactiverollingwereintroduced.Foraluminumalloythin-shellstructureswithhighstrength,weldingwillleadtohotcracking,poorjointanddistortion.Inordertosolvethem,trailingimpactivedevicewasusedbehindweldingtorchtoimpactthedifferentpositionsofweldedjoints,thusrealizingtheweldingwithfree-hotcracking,lowdistortionandjointstrengthening.Byuseofimpactiverollingwheelsinsteadofpeeningheads,theoutlookofweldedspecimencanbeimprovedandstressconcentrationatweldtoescanbereduced.Equipmentofthistechnologyissimpleandportable.Itcanusedtoweldsheets,longitudinalandring-likebeamsoftube-likestructures,aswellasthethin-shellstructureswithclosedweldssuchasflangesandhatches.Sothetechnologyhasthewideapplicationforegroundinthefieldsofaviationandaerospace.

简介：VBHF(可变空白的持有者力量)优化策略被采用决定最佳的时间变量和空间变量的BHF轨道，瞄准与铝合金表改进汽车面板的formability。策略基于适应模拟被实现模拟周围在单人赛为Numisheet'05甲板盖的每个分割的文件夹计算批评起皱BHF。在最佳的VBHF和经常的BHF下面的印上的部分的厚度比较证明分别地，四节的变化被70%，44%，64%和61%减少它在厚度分发和变化控制显示重要改进。通过种类路径比较的调查揭示formability改进的基本原因。学习与铝合金表证明新VBHF优化策略的适用性到复杂部分。

简介：AnewsimulationmodelofCO2short-circuitingtransferweldingmaybeemployedtodevelopanewpatternofweldingmachineandtopredictweldingprocessparameterstoobtaintheoptimumweldingtechnologyproperties.Inthispaper,anewsimulatingmodelisdevelopedaccordingtotheAWP(adaptingweldingphysicsprocess)waveformcontrolmethod.Goodagreementisshownbetweenthepredictedandexperimentallydeterminedresults.ThemodelwillmakeanimportantpromotioninthedevelopmentofCO2arcweldingtechnique.

简介：这篇文章介绍疲劳裂缝生长(FCG)新灼伤抵抗的高度稳定的贝它Ti40合金的行为。FCG率被分析。破裂表面和测试样品的方面表面被探索。结果证明那频率影响Ti40合金的裂开的行为。温度也在Ti40合金裂开起一个重要作用。在房间温度(25°C)，当频率增加时，裂开的率在低压力紧张因素(ΔK)的范围改变一些，当ΔK什么时候高，显著地变化时。在500°C，Ti40合金的裂开的率在裂开的所有功课期间显著地变化。频率也影响Ti40合金的微观结构模式。很多个第二等的裂缝出现在区域从在高ΔK的主要裂缝的超过200μm当频率是1Hz，而是仅仅一些时，当频率是10Hz时，第二等的裂缝存在。当频率是1Hz时，方面图象是破裂表面的主要图象。当时，当频率是10Hz时，可锻的有条纹或刻痕之状态占据大多数破裂表面的区域。

简介：Thepapergivesananalysisontechnicalcharacteristicsofrepairtechniquesforfrictionstirweldingdefects.Toovercomethedefects,anewrepairtechnique,inertiafrictionpullplugwelding(IFPPW),wasresearchedanditsequipmentwasdevelopedaswell.ElementarydatumwasachievedbyinvestigatingtheinfluencesoftechnologicalparametersonmechanicalpropertiesandbyanalyzingthestructuralcharacteristicsofrepairjointwithIFPPW.ThestudyshowsthatthestabilityandreliabilityofweldingprocessofIFPPWcanbeguaranteedthroughtheconstantenergyfromtheflywheel.Integratedwiththeadvantagesoffrictionpullplugwelding,theIFPPW,freefrombackanvil,isconsideredasapromisingtechniqueinrepairofterminationkeyholeofbobbintoolfrictionstirweldingandpoint-likedefectsinaluminumalloywelding.

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简介：ThecoercivitymechanismofNd-Fe-Bbasedmagnetspreparedbyanewtechniqueofstripcastingwasinvestigated.Differentfromthetraditionalmagnets,α-FephasesaredifficulttobefoundinNd-Fe-Bmagnetspreparedbystripcasting.Meanwhile,therich-Ndphasesoccurnotonlynearthegrainboundariesofmainphases,butalsowithinthemain-phasegrains.Investigationonthemagnetizingfielddependenceofthecoercivityforthe(Nd0.935Dy0.065)14.5Fe79.4B6.1magnetandthetemperaturedependenceofthecoercivityfortheNd14.5Fe79.4B6.1magnethavebeendone.Resultsshowthatcoercivitiesforstripcastingmagnetsarecontrolledbythenucleationmechanism.

简介：TheelectronicstructuresofspinelMgAl2O4andMgOtunnelbarriermaterialswereinvestigatedusingfirst-principlesdensityfunctionaltheorycalculations.OurresultsshowthatsimilarelectronicstructuresarefoundfortheMgAl2O4andMgOtunnelingbarriers.ThecalculateddirectenergygapsattheΓ-pointareabout5.10eVforMgAl2O4and4.81eVforMgO,respectively.BecauseofthesimilarfeatureinbandstructuresfromΓhigh-symmetrypointtoFpoint(△band),thecoherenttunnelingeffectmightbeexpectedtoappearinMgAl2O4-basedMTJslikeinMgO-basedMTJs.ThesmalldifferenceofthesurfacefreeenergiesofFe(2.9J.m-2)andMgAl2O4(2.27J·m-2)onthe{100}orientation,andthesmallerlatticemismatchbetweenMgAl2O4andferromagneticelectrodesthanthatbetweenMgOandferromagneticelectrodes,thespinelMgAl2O4cansubstituteMgOtofabricatethecoherenttunnelingandchemicallystablemagnetictunneljunctionstructures,whichwillbeappliedinthenextgenerationreadheadsorspintronicdevices.

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简介：Inthispaperanewmethodforpreventingweldinghotcracking—theinversestrainmethod(ISM)isdevelopedontheprincipleofweldingmechan-ics.EffectivenessandfeasiblityofmethodinpreventingweldinghotcrackingofhighstrengthaluminumalloyLY12CZbysynchronousrollingduringwelding(SRDW)alongbothsidesoftheweldatasuitabledistancebehindtheweldingarcareexamined.ExperimentalresulteindicatethatweldinghotcrackingofLY12CYcanbeeffectivelypreventedandthemechanicalpropertiesofweldedjointcanalsobeimprovedbythemethod.Itisanimportantnewsolutionforpreventinghotcrackinginweldingofsheetmetal.