简介：Metallurgicalmodelingofsynergisticmicrocrackself-repairmenduringweldingsinglecrystalandpolycrystallinesuperalloysofhigh-temperatureaerospacematerialshasbeenproperlyestablished.Theideaofimprovementofnickel-basedsuperalloysweldabilitythroughnon-equilibriumsolidificationbehaviorofbackfilltoself-repairarterialcracknetworkisusefullyproposed.Crystallographiccontrolstrategyofcrackself-repairmenoffusionzoneinterdendriticsolidificationcrackingandheat-affectedzone(HAZ)intergranularliquationcrackingistechnicallyachievable,indicatingthatoptimalniobiumalloyingbeneficiallyrefinesweldmicrostructure,stabilizestheprimarysolidificationpath,increasesthesolidificationtemperatureandconcomitantlydecreasestheweldpoolgeometry.High-carbongrainboundaryismorethermalstableandlesscontributestoincipientintergranularliquidfilmthanthatoflow-carbongrainboundary.Thetheoreticalpredictionsofcrackingsusceptibilityareindirectlyverifiedinarathersatisfactorymanner.Additionally,themetallurgicalmodelingenhancespredicativecapabilitiesandtherebyisreadilyapplicableforotheralloysystems.