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ID:36585962
大小:7.70 MB
页数:57页
时间:2019-05-12
《热处理对TC4-TA15焊接接头组织和力学性能影响的研究》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、大连交通大学硕士学位论文热处理对TC4/TA15焊接接头组织和力学性能影响的研究姓名:赵大伟申请学位级别:硕士专业:材料加工工程指导教师:赵秀娟;罗宇20081212人连交通大学。r:学硕十学位论文IAbstractTheuseofnewmaterialsandnewstructuresoftheaircraftiSthekeytechnologiesandtechnicaltoimprovetheperformanceofaircraftstructural.andiSalsothedirectionofdesignanddevelopment.Thetech
2、nologyofelectronbeamweldingtitaniumiswidelyusedinthefieldofaerospace,especiallyinmanufacturingtheframeworkofaircraftandtheload-bearingcomponentofenginesforitssuperiority.Howtoincreasethestabilityofthicktitaniumalloycomponentsweldedbyelectronbeamweldingisoneofthecriticalprobeem.Inthis
3、paper,twodifferenttitaniumalloymaterials,TC4/TAl5,weldedbythesameparameters,butcarriedoutbyvariousofheattreatments.Thetrendswerefoundoutbyinvestigatingthechangesofmicrostructureandmechanicalpropertiesthattheheattreatmentimpactedonthemicrostructureandthemechanicalproperties(especially
4、onthefatiguelife).Theresultsindicatedthat:themainmicrostructuresofTC4weldedbyEBWatthetopandtherootsofseamaremartensite.thecentralmicrostructuresaremartensiteeandclusterastructures.themicrostructureofHAZare0【phaseandmartensite.Aftertheisothermalheattreatment,theseammicrostructureistwo
5、-statestructureswhicharehighontheelongationandthefatigueperformances;thestructureofthebase—metaliSequiaxedstructure.ForTAl5EBWjionts,thehigherannealingtemperature,thefewernew-bom0【andsmaller0【-axis,andthephase0【inthetransitionpstructureislikethelensshape.Withtheannealingtemperaturein
6、creasing,thehardnessandtheintensityofTC4reduced,butthetoughnessandtheplasticimproved.ThestrengthoftitaniumiointsweldedbyEBWWasnotlowerthanbasemetal,thetensilefractureWasfoundonbasemetal.ThereWasnosplitsourceonthesurfaceofthetensilefractureplane,andthetypeoffracturewasthemicro—aggrega
7、tion.ThemedianfatiguelifeofTC4{TAl5jointsweresignificantlyaffectedbyheattreatment:Onconditionthattherelativeerrorwas5%,thedegreeofconfidencewas90%,themedianfatiguelifeofTC4bythereliefannealingexceed24%comparedtotheweldingjoints,andthemedianfatiguelifeofTC4bymeisothermalannealingexcee
8、d53%compared
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