{"title":"Fatigue life evaluation of laser welded lap joints of dissimilar aluminum alloys","authors":"Xiangyun Liao, Ruijie Wang, Pinglin Zhao","doi":"10.1515/mt-2024-0003","DOIUrl":null,"url":null,"abstract":"\n Constant amplitude fatigue tests were conducted on 6061/7075 dissimilar aluminum alloy laser welded lap specimens, as well as weld line cross-section hardness measurements. The fatigue test results show that the specimens exhibit multiple fracture modes that exit near the weld seam. The microhardness data on weld line cross-section from 7075 side to 6061 side display a sharp change and the softening phenomenon is serious. The hardness variation in heat affected zone of laser welding is very shallow, and its hardness is close to that of the base material. It was found that there are slag inclusions and pores in the weld seam when observing the fatigue fracture surface using SEM, and a small amount of secondary cracks were generated. However, stress concentration plays a dominant role in causing specimen fracture under fatigue loading, rather than welding defects. Defective specimens are found to have higher fatigue strength. The fatigue life prediction results obtained by the notch stress method and the hot spot stress method are both conservative and fall within two factor lines. The hot spot stress method has relatively higher accuracy for life prediction. The accuracy of both methods in predicting life is influenced by the location of the fracture.","PeriodicalId":18231,"journal":{"name":"Materials Testing","volume":null,"pages":null},"PeriodicalIF":2.4000,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Materials Testing","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1515/mt-2024-0003","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, CHARACTERIZATION & TESTING","Score":null,"Total":0}
引用次数: 0
Abstract
Constant amplitude fatigue tests were conducted on 6061/7075 dissimilar aluminum alloy laser welded lap specimens, as well as weld line cross-section hardness measurements. The fatigue test results show that the specimens exhibit multiple fracture modes that exit near the weld seam. The microhardness data on weld line cross-section from 7075 side to 6061 side display a sharp change and the softening phenomenon is serious. The hardness variation in heat affected zone of laser welding is very shallow, and its hardness is close to that of the base material. It was found that there are slag inclusions and pores in the weld seam when observing the fatigue fracture surface using SEM, and a small amount of secondary cracks were generated. However, stress concentration plays a dominant role in causing specimen fracture under fatigue loading, rather than welding defects. Defective specimens are found to have higher fatigue strength. The fatigue life prediction results obtained by the notch stress method and the hot spot stress method are both conservative and fall within two factor lines. The hot spot stress method has relatively higher accuracy for life prediction. The accuracy of both methods in predicting life is influenced by the location of the fracture.
期刊介绍:
Materials Testing is a SCI-listed English language journal dealing with all aspects of material and component testing with a special focus on transfer between laboratory research into industrial application. The journal provides first-hand information on non-destructive, destructive, optical, physical and chemical test procedures. It contains exclusive articles which are peer-reviewed applying respectively high international quality criterions.