Abstract
In this study, dissimilar aluminum alloys 2014 and 5083 have been welded using two different welding methods, namely the solid state joining method friction stir welding (FSW), and the fusion welding method tungsten inert gas welding (TIG). The joint has been investigated in terms of its microstructure, hardness and mechanical properties. Optical microscopy was used to characterize the microstructure of the weld area. Microstructural examination reveals that a fine grain structure is formed in the nugget zone of FSW as a result of recrystallization and that they are smaller in size compared to the grains in the weld center of TIG, where grain growth has been observed due to heat input. The tensile testing results show that among the two welding methods employed, FSW has yielded better mechanical properties. The mechanical strength of the dissimilar joint, both in terms of yield and ultimate tensile strengths using FSW was found to be varying for aluminum alloys 2014 and 5083 between 60 % to values matching those of the base metal values, respectively. The results show that FSW can better suit to the joining of dissimilar aluminum alloys compared to TIG welding.

Key words
friction stir welding (FSW), tungsten inert gas (TIG), dissimilar joint, aluminum alloys 2014-5083, microstructure; mechanical properties

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