金属箔材飞秒激光冲击成形实验分析

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1、万方数据江苏大学专业硕士学位论文ABSrl’RACrl’MetalfoilsarewidelyappliedinelectronicsandMEMSproductswiththedevelopmentofMEMSinrecentyears．Themanufacturingofmicropartsthroughtheshockwaveinducedbyfemtosecondlaserbegantogetattentionbecauseoftheadvantagesofgoodflexible，high

2、precisionandSOon．Researchteamshomeandabroadhaveconductedthestudyfromtheoryandexperiment．Butoverall，theresearchoffemtosecondlasershockformingisstillatprimarystage．Comparedwithnanosecondlasershockforming，femtosecondlasershockforminghasthedistinctivechara

3、cteristicsofhigherpeakpressure，higherstrainrateandSOon．Therearemuchresearchachievementsonnanosecondlasershockprocess，whichCan'tbetransplantedtothefemtosecondlasershockprocesssimply．Sotothefemtosecondlasershock，thereexisthugeresearchspaceintheory,proces

4、sing，technologyandSOon．Theexperimentalresearchoffemtosecondlasershockformingmetalfoilsisconductedinthispaper．Theultimategoalistoexploretheprocessinglawsanddeformationmechanismoffemtosecondlasershockforming．Themainresearchcontentsandconclusionsareasfoll

5、ows：(1)Theinfluencesofthepulsewidth，impacttimes，confininglayer,clampingholeonthedeformationhavebeensystematicallystudied．Theconfininglayerscontributetoimprovetheshockwavepeakpressureduringthefemtosecondlasershockforming．Andtheconstrainteffectofconfinin

6、glayerwithhighacousticimpedanceisbetterthanthatofconfininglayerwithlowacousticimpedance．Therearetwodestroyingmechanismsofconfininglayer：nonlinearabsorptionandmechanicalburst．Itisadversefortheformationofshockwaveswhenthepeakpowerdensityistoohigh，because

7、theconfininglayerwillabsorbtheincidentlaserenergythroughthenonlinearabsorption．Thenonlinearabsorptionofconfininglayerwillbeeffectivelyavoidedbyselectingtheappropriatelaserpeakpowerdensity．Thedeformationwillbecomelargerwiththedecreaseoflaserpulsewidthun

8、dertheconditionofwithoutnonlinearabsorptionandconstantlaserenergy．Thedeformationincreasewiththeshocktimesfirstlyandthentendtosaturationwhenotherparametersareconstant．Clampingholehasnoeffectonthedeformationbecauseoftheultrashortpulsewidt