文献翻译钛合金相变超塑性连接技术研究.docx
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文献翻译钛合金相变超塑性连接技术研究.docx
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文献翻译钛合金相变超塑性连接技术研究
外文资料翻译
TransformationSuperplasticityofTitaniumAlloyTechnologyResearchConnection
Theoutstandingcharacteristicoftitaniumisitshighspecificstrengthandexcellentcorrosionresistance,whileatthesametimehasgoodheatresistanceandlowtemperatureperformance,andpracticalapplicationofawiderange.Aslongasthematerialsproperly,notonlycangreatlyincreasetheeffectivenessofequipment,butalsocanbringsignificanteconomicbenefits.Inregardtocorrosionresistance,titaniumalloysinoxidizingandneutralmediaisextremelystable,thecorrosionrateinseawaterisfarbelowthestainlesssteel,comparedwithplatinum,itissuitableforthepetroleum,chemical,electricpower,metallurgy,agriculturalchemicals,paper-making,shipbuilding,foodandmedicalapplicationsandhealthdepartments.
Duetothecharacteristicsoftitaniumalloywiththeabove,itisparticularlysuitableforaircraftandspacecraftmaterialsdesignisrequired.AviationIndustryDevelopmentandApplicationoftitaniumalloysisthefirstsector.Thebeginningofthefifties,theUnitedStatessucceededintheuseofatitaniumaircraft,althoughatthetimeofeachaircraftbeingusedforonly1%theweightofthestructureoftitanium,buttitaniumhasopenedupapplicationsintheaviationindustryinthebroadroad.Now,thetitaniumintheworldhasbeenwidelyused,smallscrews,nuts,suchasconnectors,uptothefuselageframe,everyotherframe,suchasstructuralparts,andevenmorethan6meterslong,weighingtwotonsofthemainsupportbeamofthelandinggear.Forhigh-speedfighters,asaresultofhigh-speedandhighmaneuverability,theaircraftstructureasfaraspossibletherequirementsoflight,heatcapacityatthesametime;practicehasprovedthattitaniumisthemostappropriatematerial.
Titaniumistheworld'srecognizeddifficult-to-machinematerials,buttheuseofsuperplasticforming/diffusionbondingprocess(SPF/DB)canbeproducedbywelding,rivetingprocessesdifficulttoproducecomplextitaniumaircraftpartsandcomponentstoenableintegration,lightweight,andlowerthecost.
Useofmaterialsunderthermalcyclerepeatedphase-changeroleintheeffectsofpressureweldingmaterialsothatthecontacttookplaceinsuperplasticflow,sothatthesurfaceinclosecontactandclosetotheinter-atomicforcestoachievethescopeof,therealizationofthematerialonbothsidesoftheinterfaceconnectedtoareliableweldingmethodknownasphase-changeSuperplasticdiffusionbonding(TransformationSuperplasticDiffusionBonding).Superplasticconditions,thematerialunderstressinthesmallerplasticdeformationhasaverygoodabilitytoflowtheprocessofsuperplasticmaterialsinahighlyactivatedstateofatoms,thesematerialswillhelptoremovethesurfaceoxidefilmtoimprovethecombinationofthecloseconnectionsandspeeduptheatomicdiffusion,resultinginashortperiodoftimetoachieveareliableconnection.Beweldedaslongasthephase-changematerial,theuseofsuchmethodscanbewelded.Repeatedphase-changematerialisproducedbythermalcyclingtoachieve,andthereforethermalcyclingmethodhasbecomethecoreofthisweldingprocesslinks.
Phasetransformationsuperplasticdiffusionbondingisasolid-phaseweldingmethod,ageneralproliferationofweldingandthecharacteristicsofweldingdeformation,deformationmechanismsandtheproliferationofmechanismsintheformationofweldedjointsareequallyimportantroleintheprocess.Phasetransformationsuperplasticdiffusionbondingjointsorlessaftertheformationofthreephases.
First,physicalcontactwiththeformationofphases:
Totheformationoftheactualphysicalcontact,thematerialmustberemovedonthesurfaceoxidefilmandtheadsorbedlayer,butintheweldingprocessandweldingcancompletelycleartheoxidefilmisofutmostimportance.Vacuumwelding,theadsorbedlayerandtheoxidefilmunderhightemperaturedescription,distillation,evaporation,chemicalreactionanddissolutionmethodscanbeeliminated.
Intheprocessofdiffusionbonding,onlythematerialnearthesurfaceofeachother,reachingbetweenatomscanbecausedbyphysicaldistance,willitbepossibletoformaweldedjointquality.Ingeneral,thesoldermaterialswereprocessedthroughsophisticated,fromthemicro-viewofitssurfaceisstilluneven.Therefore,inthebeginningstagesofdiffusionwelding,theweldingmaterialcontactsurfacescanonlyformoflocalcontacts,whiletheremainderofthefullcontactisrequiredbytheinterfaceoftheplasticdeformationofsoldermaterial,thereisnopartofthefullcontactholesareformed,theholesontheformationofadverseeffectonjointreliability.
Phasechangematerialsinthesuperplasticdeformationresistanceunderconditionsoflowstressinthelowtothehighoccurrenceofplasticdeformation,weldinginterfaceoftheholescanexistintheroleofhigh-plasticarcheologytobefilledrapidly.Phase-changematerial,thegrainscontinuetomigrationandconversion,thesurfaceoxidefilmtobreakdownquicklybroken.Theuseofphase-changemethodofsuperplasticdiffusionbondingcanbesmallerunderthepressureoftherapidrealizationoffullyweldedjointphysicalcontact.
Second,chemicalinteractionofstages:
Theformationoftheactualcontactandthesurfaceisnotenoughtohaveastrongconnectionbetweenatoms.Inordertoobtainthecombinationofatomsbetweenthesolid,itisnecessarytoactivatethesurfaceatoms.Activationofthesurfaceatomswillleadtotheoriginalbond(forexample,thechemicaladsorptionandoxygenlevel)ofthetear,andthenwillitbepossibletomaketheelectronicinteractionsbetweenatoms.Underthemetalintheexternalforcegeneratedbyshearstressandnormalstresscancausethemetalsurfaceoftheplasticdeformationandflow,plasticdeformationandflowofcausedefectsinthecrystalstructure(dislocationsandhole)tomovetothesurfaceatthistime,defectmigrationthereleaseofatomicenergywillactivatethesurface,theformationofactivationcenters.Ifthehighertemperature,thesurfacewillactivatethenumberofcentersisincreasingrapidly.Surfaceandthenweldedbetweenthetwohastoactivatetheinteractionbetweentheatomscombine.
TransformationSuperplasticitymakeplasticweldingsurfacearcheology,thearcheologyofplastictobrokenoxidefilmandincreasethedislocationdensityandtheholewiththespeedofmigration.Afterbreakingtheoxidefilmtoforma"fresh,thesurface,thissurfacehasahigherdegreeofchemicalactivity.Atthesametime,phasechangeasaresultofrecrystallizationanddynamicrecrystallizationoftherepeatedchangesinthegrainboundaryandrepeatedmigration,sothatatomshaveahighinterfaceactivity.
Third,theinteractionofbodyphases:
Isthroughacombinationofmetalmaterialsforthespreadaroundthestage.Inweldingwiththemetal,thesignoftheendofthethirdphaseisgeneratedinthejointoftherecrystallizationprocess,acommongrain.Dissimilarmetalwelding,whetherornottolimitthespreadofthethirdphaseoftheprocessdependsonthenatureoftheproliferationzoneandtheresultingnatureofthenewphase.TransformationSuperplasticityofthetremendousroleinpromotingproliferation,couldhavebeenweldinginashorttime.
Applicationofsuperplastictitaniumalloyconnectivityfeatures:
First,canthepastbyanumberofpartsbymechanicalconnectionorweldingtogetherthemajorcomponentsassembledinaheated,pressurizedprocessofformingtheoverallstructureforlargepieces,greatlyreducingthenumberofpartsandtoolingtoshortenthemanufacturingcycle,reducedthemanufacturingcost.
Second,designerscanprovidegreaterflexibilitytodesignamorerationalstructuretofurtherimprovetheefficiencyofthestructuralloadtoreducethestructuralweight.
Third,theuseofthistechnologytocreatecomprehensivemapsofthestructure,andmaterialafterthediffusionbondinginterfacecompletelydisappeared,sothattheentirestructureasawhole,hasgreatlyimprovedthestructureoftheanti-fatigueandanti-corrosionproperties;andthroughappropriatestructuraldesigncanalsoimprovethestructureofthebendingrigidity,andexpandthescopeofapplicationoftitaniumalloys.Industrialbase,suchasairdaysofthetitaniumalloyusedincoldformingandmachiningisverydifficulttomakeitpracticalsubjecttocertainrestrictions,SPF/DBtitaniumtechnologyenablesasimplemanufacturingprocess,canbeachievedalmostatthesametimemorethantechnologyThepreciseamountofprocessing,improvedmaterialutilization,reducedproductioncosts.
Fourth,thematerialintheprocessofsuperplasticformingcanwithstandgreatdeformationwithoutrupture,youcanshapethestructureofaverycomplexmatter,whichistheconventionalmethodofcoldformingthebasicshapecannotdoorneedtobeachievedonmanyoccasions.Superplasticformingmaterialinthecourseofflowstressisverysmall,thiscanbeusedinsmalltonnageofequipmentformingthestructureoflargepiecesofthestructureandprocessingofnon-resilient,non-residualstress,high-precisionforming.
U.S.aircraftmanufacturerintheearlyseventiesbegantostudythesuperplasticformingtechnologyoftitaniumalloy(SPF),in899~927℃hightemperatureandstrainrateof10-4cm/sundertheconditionssothatanextensionoftitaniumalloysrateof60to1000%,thesampleformingprocessavacuumformingplasticboardasthesamedoesnotoccurinthecaseofneckingandfractureundertheuniformdeformationofthecomplex.
Atpresent,theUnitedStateshasinthef
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