外文翻译--摩擦搅拌焊接技术及其发展过程.doc

外文翻译毕业设计题目：双搅拌轴搅拌摩擦焊机设计原文：FIRCTIONSTIRWELDINGANDPROCESSING译文：摩擦搅拌焊接技术及其发展过程（原文2）FIRCTIONSTIRWELDINGANDPROCESSINGAbstractFrictionstirwelding(FSW)isarelativelynewsolid-statejoiningprocess.Thisjoiningtechniqueisenergyefficient,environmentfriendly,andversatile.Inparticular,itcanbeusedtojoinhigh-strengthaerospacealuminumalloysandothermetallicalloysthatarehardtoweldbyconventionalfusionwelding.FSWisconsideredtobethemostsignificantdevelopmentinmetaljoininginadecade.Recently,frictionstirprocessing(FSP)wasdevelopedformicrostructuralmodificationofmetallicmaterials.Inthisreviewarticle,thecurrentstateofunderstandinganddevelopmentoftheFSWandFSPareaddressed.Particularemphasishasbeengivento:(a)mechanismsresponsiblefortheformationofweldsandmicrostructuralrefinement,and(b)effectsofFSW/FSPparametersonresultantmicrostructureandfinalmechanicalproperties.Whilethebulkoftheinformationisrelatedtoaluminumalloys,importantresultsarenowavailableforothermetalsandalloys.Atthisstage,thetechnologydiffusionhassignificantlyoutpacedthefundamentalunderstandingofmicrostructuralevolutionandmicrostructurepropertyrelationships.#2005ElsevierB.V.Allrightsreserved.1.IntroductionThedifficultyofmakinghigh-strength,fatigueandfractureresistantweldsinaerospacealuminumalloys,suchashighlyalloyed2XXXand7XXXseries,haslonginhibitedthewideuseofweldingforjoiningaerospacestructures.Thesealuminumalloysaregenerallyclassifiedasnon-weldablebecauseofthepoorsolidificationmicrostructureandporosityinthefusionzone.Also,thelossinmechanicalpropertiesascomparedtothebasematerialisverysignificant.Thesefactorsmakethejoiningofthesealloysbyconventionalweldingprocessesunattractive.Somealuminumalloyscanberesistancewelded,butthesurfacepreparationisexpensive,withsurfaceoxidebeingamajorproblem.Frictionstirwelding(FSW)wasinventedatTheWeldingInstitute(TWI)ofUKin1991asasolid-statejoiningtechnique,anditwasinitiallyappliedtoaluminumalloys1,2.ThebasicconceptofFSWisremarkablysimple.Anon-consumablerotatingtoolwithaspeciallydesignedpinandshoulderisinsertedintotheabuttingedgesofsheetsorplatestobejoinedandtraversedalongthelineofjoint(Fig.1).Thetoolservestwoprimaryfunctions:(a)heatingofworkpiece,and(b)movementofmaterialtoproducethejoint.Theheatingisaccomplishedbyfrictionbetweenthetoolandtheworkpieceandplasticdeformationofworkpiece.ThelocalizedheatingsoftensthematerialaroundthepinandcombinationoftoolrotationandtranslationleadstomovementofmaterialfromthefrontofFig.1.Schematicdrawingoffrictionstirweldingthepintothebackofthepin.Asaresultofthisprocessajointisproducedinsolidstate.Becauseofvariousgeometricalfeaturesofthetool,thematerialmovementaroundthepincanbequitecomplex3.DuringFSWprocess,thematerialundergoesintenseplasticdeformationatelevatedtemperature,resultingingenerationoffineandrecrystallizedgrains47.Thefinemicrostructureinfrictionstirweldsproducesgoodmechanicalproperties.FSWisconsideredtobethemostsignificantdevelopmentinmetaljoininginadecadeandisagreentechnologyduetoitsenergyefficiency,environmentfriendliness,andversatility.Ascomparedtotheconventionalweldingmethods,FSWconsumesconsiderablylessenergy.Nocovergasorfluxisused,therebymakingtheprocessenvironmentallyfriendly.Thejoiningdoesnotinvolveanyuseoffillermetalandthereforeanyaluminumalloycanbejoinedwithoutconcernforthecompatibilityofcomposition,whichisanissueinfusionwelding.Whendesirable,dissimilaraluminumalloysandcompositescanbejoinedwithequalease810.Incontrasttothetraditionalfrictionwelding,whichisusuallyperformedonsmallaxisymmetricpartsthatcanberotatedandpushedagainsteachothertoformajoint11,frictionstirweldingcanbeappliedtovarioustypesofjointslikebuttjoints,lapjoints,Tbuttjoints,andfilletjoints12.ThekeybenefitsofFSWaresummarizedinTable1.Recentlyfrictionstirprocessing(FSP)wasdevelopedbyMishraetal.13,14asagenerictoolformicrostructuralmodificationbasedonthebasicprinciplesofFSW.Inthisc