Modern fiber laser beam welding of thenewly-designed precipitation-strengthened nickel-base superalloys

In thepresentresearch,themodern fiber laserbeamweldingofnewly-designedprecipitation- strengthened nickel-basesuperalloysusingvariousweldingparametersinconstantheatinputhasbeen investigated.Fivenickel-basesuperalloyswithvariousTiandNbcontentsweredesignedandproduced by VacuumInductionMeltingfurnace.The fiber laserbeamweldingoperationswereperformedin constant heatinput(100Jmm2) anddifferentweldingpowers(400and1000W)andvelocities(40and 100mms1) using6-axisanthropomorphicrobot.Themacro-andmicro-structuralfeatures,weld defects, chemicalcompositionandmechanicalpropertyof3.2mmweldmentswereassessedutilizing optical andscanningelectronmicroscopesequippedwithEDSanalysisandmicrohardnesstester.The results showedthatweldingwithhigherpowerscancreatehigherpenetration-to-widthratios.The porosity formationwasincreasedwhentheweldingpowersandvelocitieswereincreased.Noneofthe welds displayedhotsolidification andliquationcracksin400and1000Wweldingpowers,butliquation phenomenon wasobservedinalltheheat-affectedzones.WithincreasingtheNbcontentofthe superalloystheliquationlengthwasincreased.Thechangingoftheweldingpowerandvelocitydidnot alter thehardnesspropertyofthewelds.ThehardnessofweldsdecreasedwhentheTicontentdeclined in thecompositionofsuperalloys.Finally,the400and1000W fiber laserpowerswithvelocityof40and 100mms1 havebeenofferedforhotcrack-freeweldingofthethinsheetofnewly-designed precipitation-strengthenednickel-basesuperalloys.