简介:TheeffectofLaelementonthemechanicalpropertiesandconstitutionnearbygrainboundaryinaCo-basesuperalloyCo-22Ni-22Cr-14kduring760℃ageinghasbeeninvestigatedbyAESandmaterialtesting.ResultsshowthatelementLacanbeinastateofsolidsolutionandsegregatesmainlyatthevicinityofgrainboundaries.ThepriorsegregationofLaatomscanaffectsegregationbehaviourofotherelements,sothatexertsinfluenceonmicrostructureofthealloy,ParticularlyincreasingofLacontentcandecreasePconcentrationatthevicinityofgrainboundariesbutnotdecreaseSconcentration.StogetherwithLaproducecosegregationeffect.ThecontentofLahasnoobviouseffectonhightemperaturestrength.WhenthecontentofLacomesupto0.02wt-%,itcanobviouslyimprovethehightemperatureductility.
简介:Rare-earthcoordinationpolymers(RECPs),asafamilymemberofcoordinationpolymers(CPs),havebeenpreparedandstudiedwidely.Thankstotheircharacteristicpropertiesandfunctions,RECPshavealreadybeenusedinvariousapplicationfieldsrangingfromcatalysistodrugdelivery.Inrecentyears,CPswithtunablemorphologiesandsizeshavedrawnincreasinginterestandattractiveattention.ThisreviewpresentstherecentresearchprogressofRECPmicro/nanomaterials,andemphasizesthepreparation,propertiesandbroadapplicationsofthesefascinatingmaterials.
简介:AnewmethodforcorrosionprotectionofAl-basedmetalmatrixcomposites(MMC)wasdevelopedusingtwo-stepprocess,whichinvolvesanodizinginH2SO4solutionandsealinginrareearthsolution.Corrosionresistanceofthetreatedsurfacewasevaluatedwithpolarizationcurves.TheresultsshowedthattheeffectoftheprotectionusingrareearthsealingisequivalenttothatusingchromatesealingforAl6061/SiCp.TherareearthmetalsaltcanbeanalternativetothetoxicchromateforsealinganodizedAlMMC.
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简介:TechnologicalprocessofrareearthsealinganodizedLY12(2024)alloyisintroduced.Corrosionbehaviorofthefilmwasstudiedbypolarizationcurvesandelectrochemicalimpedancespectroscopy(EIS).Theresultsshowedthatthecoatingremainedpassivityatthepotentialrangefromtheopencircuitpotential(-780mV)to-250mVinNaClsolution.Whenthepotentialexceeded-200mV,corrosionreactionhappenedonthecoating.theresultsofElSanalysiswasconsistentwiththeresultsofpolarizationcurves.
简介:Anumberoftechniqueshavebeendevelopedtosynthesizenanocrystallinebulkmaterials,includinginert-gascondensationandconsolidation,electrodeposition,severeplasticdeformation,crystallizationofamorphoussolid,surfacemechanicalattrition,andpowdermetallurgy.However,itishardtoproducethebulkwithcontrollablenanostructures,especiallywiththegrainsizescontrollableinawiderangebelow100nm.Intheconventionalpowdermetallurgy,duetothefactthatrapidcoarseningoftheparticles...