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《ti2alnb基合金的熱變形行為及加工圖研究》由會員上傳分享，免費在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫。
1、AbstractTi2AlNb-basedalloyisadvancedstructuralmaterialappliedinairlineandindustryandhascomprehensivelyexcellentmechanicalpropertiesinhighspecificstrength,specificstiffness,fracturetoughnessandcreepresistance.Therefore,Ti2AlNb-basedalloyisanewstudyhot-spotininte
2、rmetalliccompoundresearchfieldwithagreatrangeofpotentialutilitiesandaprospectofdevelopment.However,Ti2AlNb-basedalloyisdifficult-to-deformationmaterial.Itsorganizationandpropertyareextremelysensitivetothedeformationparameters,soit’shardtogetproductsstableinorga
3、nizationandproperty,andthehighcostofmanufacturerestrictsitsapplicationrange.ThispaperconsidersTi2AlNb-basedalloy.Theisothermalconstantstrainratecompressionexperimentswereconductedbetween900~1110℃and0.01~10s-1deformationparameter.Theauthoranalyzedthetruestress-s
4、traincurves,calculatedthisalloy’sactivationenergyandconstructedaconstitutiveequationwithhighaccuracy.ProcessingmapsindifferentdependentvariablesweredrewaccordingtoPrasadandMurtycriterions.Theauthoralsostudiedtheanalysisdiagramwiththemicrostructureandgottheinsta
5、bilityregions,thebetterhotworkingareaanditscorrespondingthermodynamicparametersanddeformationmechanism.Mainresultsareasfollows.FlowstresscurveofTi2AlNb-basedalloyhasfeatureslikestresspeak,flowsofteningandsteadystateflow.Flowstressdecreaseswiththeincreaseofdefor
6、mationtemperatureandthedecreaseofstrainrate.Accordingtothecalculation,Ti2AlNb-basedalloy’sactivationenergyQ=358.24KJ/mol,whichisobviouslybiggerthanselfdiffusionactivationenergyofpureαtitaniumandpureβtitaniumalloy.ThisshowsthatthermaldeformationofTi2AlNb-basedal
7、loyiscontrolledbyprocesseseliminatehightemperaturediffusion.Aconstitutiveequationwithhighaccuracyisconstructed,andtheerroranalysisshowsthatinallthedatapoints,datapointsoflessthan15%errorsaccountedfor93.8%and90.8%.Processingmapsindifferentdependentvariableswered
8、rewaccordingtoPrasadandMurtycriterionsseparately.Bythecomparisonofthesetwokindsofprocessingmaps,theauthorfoundthatthistwohasasimilarpredictionofinstabilityregion,butwhencons
