ly12铝材料性能退化的非线性效应检测方法分析

《ly12铝材料性能退化的非线性效应检测方法分析》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、北京工业大学工学硕士论文ⅡJJ一●^J6J'AbstractAbs仃actInservicecomponentsofmechanicalequipmentandengineeringstructuresareoftensubjectedtocyclicloading．Therefore，thedevelopmentofmaterialsandstructuresofearlyperformancedegradationofthemonitoringandforecastingtoolisveryimportant．Mostmaterialpropertieschanges，sucha

2、smechanicalmacroscopicmechanicalpropertiesofmaterialsaging，degradationoftensileproperties，fatigue，creepdamageandbondingmaterials，haveinherentconnectionwithorganizationalstructure．Inthispaper，themechanicalpropertiesofmetalfatiguedegradationoftheearlystudiesfocusedonmacro--micro··crackscallbeseen

3、beforethestageofthedegradationofmaterialproperties．Constructionofthemacro-mechanicalperformancedegradation—changesincontactmorphology,orstructurefortheequipmentuseandmaintenanceandprovideatheoreticalbasis．Themaintasksareasfollows：(1)Combinedwiththetheoreticalbasisofnonlinearultrasonictesting，bu

4、ildingtestplatforms．Forsystemstabilityoffactoranalysis．thestabilityofthedetectionsystemofmeasurementresults．Usingtheoptimizedsystem．(2)Ultrasonicmethodusingnonlinearfiniteamplitudemethod,characterizedbyrelativelynon—linearitycoefficientparameters8／8a．Off-linedetectionoffatiguespecimenswithmacro

5、scopicnonlinearcoefficientandtherelativenumberofweeksthevariationoffatigue，andapreliminarystudyusingsignalprocessingmethodsonmeasurementresults．(3)Offiinefatiguespecimens，usingopticalobservationmethodintheopticaletchingmethodandtransmissionelectronmicroscopy．Observedmorphologyoftheopticalimaget

6、hereisonlydifference，andthemicroandmacroparametersoftherelativesizeofnon-linearcoefficientchangeswiththecorrespondingrelationship；observedbytransmissionelectronmicroscopyimages，thereisanextensionofdislocationloopsanddislocationlines，andstresspatterns，andbyEDSanalysisidentifiedthechemicalcomposi

7、tionofaluminumalloyLYl2．(4)On-linefatiguespecimens，inordertOfurtherdeterminetherelativenonlinearcoefficientsofmacroweekswiththeincreaseinfatiguecharacteristicsofcontinuouschange，on—lineinspectiontest；andconductedinsituobservationo