简介:Inthispaper,thebrazingmechanismofLY12aluminumalloyatmiddlerangetemperaturewaspresented.TheCsF-AlF3non-corrosivefluxwasutilizedtoremovethecomplexoxidefilmonthesurfaceofLY12aluminumalloy.TheresultsrevealedthattheoxidefilmwasremovedbytheimprovedCsF-AlF3fluxaccompaniedwiththeoccurrenceofreactionaswellasdissolutionandthecompoundsCsFplayedanimportantroletoremovetheoxidefilm.Actually,thehighactivityofflux,say,theabilitytoremovetheoxidefilm,wasduetothepresenceofthecompounds,suchasNH4F,NH4AlF4andcompositemoltensalt.TheproductionofHFwasthekeyissuetoacceleratethereactionandenhancetoeliminatetheoxidefilmbydissolution.ItwasfoundthattherareearthelementLaatsmallpercentagewasnotenrichedattheinterface.Moreover,therareearthfluorideenhancedthedissolutionbehavior.
简介:Anewenvironmentalfriendlycatalyst,H4SiW12O40/PAnwaspreparedandidentifiedbymeansofFT-IR,XRDandTG/DTA.Cyclohexanone1,2-propanediolketalwassynthesizedfromcyclohexanoneand1,2-propanediolinthepresenceofH4SiW12O40/PAn.Thefactorsinfluencingthesynthesiswerediscussedandthebestconditionswerefoundout.Theoptimumconditionsare:molarratioofcyclohexanoneto1,2-propanediolis1:1.4,thequantityofcatalystisequalto1.0%offeedstocks,andthereactiontimeis40min.H4SiW12O40/PAnisanexcellentcatalystforsynthesizingcyclohexanone1,2-propanediolketalanditsyieldcanreachover96.5%.
简介:ThevacuuminductionbrazingofSiCparticulatereinforcedLY12alloymatrixcompositeusingAl-28Cu-5Si-2Mgfillermetalhasbeencarriedout.Themicrographofthejointinterfacewasobservedbyscanningelectronmicroscopy.Thejointstrengthwasdeterminedbysheartests.Theresultsshowthatbrazingtemperature,holdingtime,SiCparticlevolumepercentageandpostheattreatmentinfluencejointstrength.SiCparticleshappeninthebrazingseamandthedistributionofSiCparticlesinthejointisnotuniform.Particle-poorzonesinthejointexistnearthebasemetal,andparticleconcentratezonesexistinthecenterofthebrazingseam.Inaddition,thefailureofthecompositeispredominantlyinitiatedbytherootingofSiCparticleinthebrazingseamandthemicro-crackexpandedalongthebrazingseamwithlowenergy.
简介:Inthispaperanewmethodforpreventingweldinghotcracking—theinversestrainmethod(ISM)isdevelopedontheprincipleofweldingmechan-ics.EffectivenessandfeasiblityofmethodinpreventingweldinghotcrackingofhighstrengthaluminumalloyLY12CZbysynchronousrollingduringwelding(SRDW)alongbothsidesoftheweldatasuitabledistancebehindtheweldingarcareexamined.ExperimentalresulteindicatethatweldinghotcrackingofLY12CYcanbeeffectivelypreventedandthemechanicalpropertiesofweldedjointcanalsobeimprovedbythemethod.Itisanimportantnewsolutionforpreventinghotcrackinginweldingofsheetmetal.
简介:为了推动防腐蚀技术进步和创新,需要加强与国际间的交流。本文介绍了第12届亚太腐蚀控制会议情况,以及参加这次会议的收获和体会。
简介:Themicrostructuresofas-castandas-solutionMg–12Gd–2Er–1Zn–0.6Zralloyswereinvestigatedbyopticalmicroscopy(OM),scanningelectronmicroscopy(SEM),transmissionelectronmicroscopy(TEM),highresolutiontransmissionelectronmicroscopy(HRTEM)X-raydiffraction(XRD)andselected-areaelectrondiffraction(SAED)inthepresentinvestigation.TheresultsshowthattheprimaryeutecticphaseMg5(Gd,Er,Zn)andsomeflocculentfeaturesarefoundintheas-castalloy;theSAEDpatternindicatesthattheseflocculentfeaturesarethedenseareasofstackingfaults.The14H-LPSOstructureprecipitatesinthetemperaturerangeof673–793K,andthevolumefractionof14H-LPSOstructureincreaseswiththeextensionofheatingtime;however,thereisnoprecipitationof14H-LPSOstructurewhenthetemperaturereachesupto803K.Inaddition,theMg5(Gd,Er,Zn)phasedissolvesgraduallyalongwiththeprecipitationof14H-LPSOstructure.