激光喷丸强化ti-6al-4v航空钛合金疲劳裂纹扩展性能分析

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1、江苏大学硕士学位论文LaserPeening(")technologyisanewsurface—treatingmethodofmaterials，whichemployshighamplitudeshockwavepressureinducedbytheinteractionbetweenlaserandmaterialtointroduceplasticdeformation，grainrefinement，densedislocationonthesurfaceofmaterials．Meanwhile，thed

2、eepercompressiveresidualstressthanconventionallyshotpeeningisachievedtoimprovetheanti-fatiguepropertyofmaterialsandenhancethefatiguepropertyofcriticalcomponents，slowdownthefatiguecrackgrowthrate，andiswidelyusedinaerospaceandaeronauticalfields．Thispaperisbasedonli

3、nearandelastic-plasticfracturemechanics，Ti-6AI-4Vtitaniumalloyistakenasresearchobjective．ResidualstressdistributionandfatiguecrackgrowthpropertyoftitaniumalloysheetstreatedbyLPwerestudied，andthepapermainlyfocusesonthefollowingaspects：Thedistributionofresidualstre

4、ssofTi-6A1-4Vtitaniumalloywasanalyzed，theeffectsofresidualstressonfatiguecrackgrowthpropertieswereresearched；thefatiguecrackgrowthrateandlifeunderdifferentcontrollparameterswassummedupbasedonlinearandelastic-plasticfracturemechanics，meanwhile，themicro-mechanisman

5、dfracturemechanicsdescriptionoffatiguecrackgrowthwereanalyzed；discussedtheimprovementofLPonfatigueperformancefromfouraspects．Thehigh··powersolid·-statelaserwasusedintheexperimentstocarryouttheLPprocessonCTsamplesunderdifferentcoverageratesanddifferentlaserpoweren

6、ergies．ResidualstressdistributionwasmeasuredusingX-raydiffractionequipment．MTS-809electro·hydraulicservotestsystemwasadoptedtoperformthefatiguecrackgrowthexperiment，atthesametime，fatiguelifeandcrackgrowthratewerebothstudiedwhichverifiedthatLPcandecreasefatiguecra

7、ckgrowthrateoftitaniumalloyapparently,andenhancefatiguelifeofsamples．FatiguefracturemorphologywasanalyzedbySEM，thevariationofmorphologyoncrackinitiation，crackgrowthstage，fracturestagewerecompared，studiedthelocationofcrackinitiation、thefatiguestriationspacing、thed

8、implesbeforeandafterLP,illustratedtheeffectsofLPonfatiguecrackratefrommicro-mechanism，verifiedthevalidityofLPonimprovingfatiguepropertyoftitaniumalloy．TheABAQU