划痕诱发的镍基合金应力腐蚀裂尖扩展驱动力分析（英文）

划痕诱发的镍基合金应力腐蚀裂尖扩展驱动力分析（英文）Analysis of Stress Corrosion Crack Tip Extension Driven by Scratches in Ni

划痕诱发的镍基合金应力腐蚀裂尖扩展驱动力分析 （英文） AnalysisofStressCorrosionCrackTipExtensionDrivenby ScratchesinNickel-BasedAlloys Nickel-basedalloysarewidelyusedinvariousengineering applicationsduetotheirexcellentmechanicalandcorrosion resistanceproperties.However,theyarestillsusceptibletostress corrosioncracking(SCC)undercertainenvironmentalandloading conditions.Scratchesonthesurfaceofnickel-basedalloyscan serveasinitiationsitesforSCC,andthepropagationofSCCcracks isoftendrivenbythestressconcentrationatthecracktip. Inthispaper,wefocusontheanalysisofthestresscorrosion cracktipextensiondrivenbyscratchesinnickel-basedalloys.The scratch-inducedstressconcentrationatthecracktipisfirst analyzedusingfiniteelementanalysis(FEA).TheFEAresultsshow thatthestressconcentrationfactorcanreachahighvalueofupto 10forascratchdepthof50μm.Thestressconcentrationiseven moreseverefordeeperscratches. Next,theSCCcracktipextensionbehaviorisstudiedusinga crackgrowthmodel.Thecrackgrowthrateisdeterminedbased ontheParislaw,whichrelatesthecrackgrowthratetothestress intensityfactor(K)asda/dN=C(ΔK)n,whereda/dNisthecrack growthrate,Candnarematerialconstants,andΔKisthestress intensityrange.Thestressintensityrangecanbecalculatedusing thestressconcentrationfactorandtheappliedloading. Thecrackgrowthbehaviorisanalyzedfordifferentloading conditions,includingstaticandcyclicloading.Forstaticloading, thecrackgrowthrateisfoundtoincreaselinearlywiththeapplied stressintensityrange.However,forcyclicloading,thecrack growthrateishigherforagivenstressintensityrangeduetothe cyclicallyinducedplasticityatthecracktip. Finally,theeffectofenvironmentontheSCCcracktip extensionbehaviorisinvestigated.Itiswellknownthatthe presenceofcertaincorrosiveenvironmentscansignificantly acceleratetheSCCcrackgrowthrate.Theeffectofenvironment canbeincorporatedintothecrackgrowthmodelthroughtheuse