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《ti-6al-4v與sic超聲波釬焊界面形成機(jī)理與工藝分析》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在行業(yè)資料-天天文庫(kù)。
1、哈爾濱工業(yè)大學(xué)工學(xué)碩士學(xué)位論文AbstractSiliconcarbide(SiC)ceramicshavebroadapplicationprospectsinindustry,suchasmachine,aerospace,petroleum,nuclearenergy,opticsandotherfields,duetotheirgoodperformancesofstrongoxidationresistance,goodabrasionresistance,highhardness,goodtherm
2、alstability,lowcoefficientofthermalexpansion,highthermalconductivity,excellentthermalshockresistance,etal.Ti-6Al-4Vtitaniumalloyswithhighstrength,corrosionresistanceandotheroutstandingadvantagesarewidelyusedinaerospace,petrochemicalandotherfields,andbecomeim
3、portantstructuralmaterials.ResearchonproducingSiCceramic/Ti-6Al-4Valloycompositecomponentsisveryimportantfortheirapplication.SothepapermadeaseriesofstudiesontheSiCceramicandTi-6Al-4Valloy.ThemechanismonthewettingandbondingofAl-12Sibrazingalloytothetwokindsof
4、basematerialsundertheeffectofultrasonicvibrationweresystemicstudied,andtheultrasonicbrazingtechnologytoobtainedlowthermalstressjointswasproposed.Therearetwomainaffectsonthemechanicalpropertiesofthebrazedjoints:thepoorwettabilityandbadbondingbetweenthebrazing
5、alloyandthebasematerialsinair;thelargerresidualthermalstressinthebrazedjointduetothemismatchofthermalexpansioncoefficientbetweenSiCceramicandTi-6Al-4Valloy.TheultrasonicassistedinteractionbehaviorsbetweenAl-12SibrazingalloyandTi-6Al-4Valloywerestudied.Experi
6、mentalresultsshowedthatnumerous2–20μmdiameter-sizedandhemisphericalpitsformedontheTi-6Al-4Vsurface.Thenumberofpitsincreasedwithprolongingtheultrasonicvibrationdurationtime,butthereisnosignificantchangeintherangeofpitdiameterswithincreasingtheultrasonicvibrat
7、iondurationtime.Theformationofpitswasresultfromtheimplosionofthecavitationbubblesoccurredatorneartheinterface(cavitaionerosion).Theimpactofmicro-jetsinducedbybubbleimplosionresultedinbreakageoftheoxidefilmontheTi-6Al-4Vsurface,andthesolidTi-6Al-4Visexcessive
8、lydissolvedintoliquidAl-12Siatthenotchesundertheeffectsofhotspotsandultrasonicstir,then,abnormalconditionsestablishedbybubbleimplosionmadedifferentintermetalliccompoundsformedattheinterface(gran
