Lap shear strength and fatigue behavior of friction stir spot welded dissimilar magnesium-to-aluminu.pdf

Materials Science Engineering A 562 (2013) 53–60Contents lists available at SciVerse ScienceDirectMaterials Science Engineering A0921-50 http://d n Corr E-mjournal homepage: /locate/mseaLap shear strength and fatigue behavior of friction stir spot welded dissimilar magnesium-to-aluminum joints with adhesiveS.H. Chowdhury a, D.L. Chen a,n, S.D. Bhole a, X. Cao b, P. Wanjara b a Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada b National Research Council Canada Aerospace, 5145 Decelles Avenue, Montreal, Quebec H3T 2B2, Canadaa r t i c l e i n f o Article history: Received 1 September 2012 Received in revised form 11 November 2012 Accepted 12 November 2012 Available online 19 November 2012 Keywords: Magnesium alloy Aluminum alloy Adhesive Friction stir spot welding Lap shear strength Fatigue properties93/$ - see front matter 2012 Elsevier B.V. A /10.1016/j.msea.2012.11.039 esponding author. Tel.: t1 416 979 5000x64 ail address: dchen@ryerson.ca (D.L. Chen).a b s t r a c t Lightweighting is currently considered as an effective way in improving fuel efficiency and reducing anthropogenic greenhouse gas emissions. The structural applications of lightweight magnesium and aluminum alloys in the aerospace and automotive sectors unavoidably involve welding and joining while guaranteeing the safety and durability of motor vehicles. The objective of this study was to evaluate the lap shear strength and fatigue properties of friction stir spot welded (FSSWed) dissimilar AZ31B-H24 Mg alloy and Al alloy (AA) 5754-O in three combinations, i.e., (top) Al/Mg (bottom), Al/Mg with an adhesive interlayer, and Mg/Al with an adhesive interlayer. For all the dissimilar Mg-to-Al weld combinations, FSSW induced an interfacial layer in the stir zone (SZ) that was composed of intermetallic compounds of Al3Mg2 and Al12Mg17, which led to an increase in hardness. Both Mg/Al and Al/Mg dissimilar adhesive welds had sign