简介:AhighalloyedVanadis4(V4)steelwasproducedbysprayformingprocessinBaosteel,andthemicrostructureoftheas-sprayedsteelanditsevolutionduringhotrollingandannealingprocesseswerecharacterized.Itwasfoundthattheas-sprayedV4steelhasahomogeneousandfinescalemicrostructurewithuniformdispersionofcarbides.Thehotrollingtemperatureisthekeyfactorincontrollingtheevolutionoftype,morphologyanddistributionofcarbides,aswellasthematrixmicrostructureoftheas-rolledsteels.Theoptimizedprocessingparametersfortheas-sprayedV4steelarerollingat1050℃andthenannealingat900℃.Themicrostructuralevolutionmechanismsduringhotrollingandannealingaredeterminedaccordingtothemicrostructuralanalyasisofthematerialatdifferentstages.
简介:Hydrogen,asatemporaryelementintitaniumalloys,isverygoodincontrollingmicrostructure.ThemicrostructureandphasetransformationofTi6A14ValloyareaffectedbytheamountofTiH,addedintothemeltofTi6A14Valloyduringtheinductionskullmelting(ISM)process.Thisprocess,calledmelthydrogenation,wasstudiedinthispaperthroughtheuseofopticalmicroscopy,scanningelectronmicroscopy(SEM)andtransmissionelectronmicroscopy(TEM).Theresultsareasfollows:aftermelthydrogenation,boththesolidificationmacrostructureandmicrostructureofTi6A14Valloyarerefined;theαphaseprecipitatesinalamellarformwiththeresidualβphasefromthegrainboundaries;δ-hydridesprecipitateduringthesolidificationprocessasaresultoftheexistenceofhydrogen.TheSphasewithanF.C.C.structurecanbeobservedbyTEMintheαphaselaminaeofspecimenswith1.25%TiH2.Inaddition,thedependenceofthemicrohardnessofspecimensontheweightpercentageofTiH,addedtothemeltduringtheISMprocesswasalsostudied.