This paper compares, the mechanical properties of welded joints 6061 T6 and 5083 O aluminium alloys obtained using friction stir welding (FSW) at four rotation speeds namely 450,560,710 and 900 rpm and that by conventional fusion welding. FSW welds were carried out on a milling machine. The performance of FSW and Fusion welded joints were identified using tensile test, hardness test and microstructure. The properties of FSW and fusion welded processes were also compared with each other to understand the advantages and disadvantages of these processes for welding applications for Al alloys. It was seen that the tensile strength obtained with FSW was higher as compared to conventional fusion welding process. The width of the heat affected zone of FSW was narrower than Fusion welded joints. The results showed that FSW improved the mechanical properties of welded joints.
 G. Madhusudhan Reddy, “Aluminium welding”, in Recent Developments in Materials Joining, pp. 175-190, AICTE, Annamalai Nagar, 2001.
 K.V. Jata,t “Friction stir welding effects on microstructure and fatigue of aluminium alloy 7075-T7451”, Metallurgical Materials Trans. 31A, 2181-2192 (2000).
 S. Kalpakjian, Manufacturing Engineering Technology, p. 36, Addison-Wesley, Boston, 1995.
 K. Elangovan and V. Balasubramanian, “Influences of postweld heat treatment on tensile properties of friction stir-welded AA6061 aluminum alloy joints”, 2008, Materials Characterization 59 (9), 1168-1177 (2008).
 K. Mustafa, K. Erdinc, S. Aydin, and B. Ozden, “Experimental comparison of MIG and Friction stir welding processes for EN AW6061-T6 (Al Mg1 Si Cu) aluminium alloy”, Arabian J. Science and Engineering 35 (1 B), CD-ROM (2010).
 N. Shanmuga Sundaram and N. Murugan, “Tensile behavior of dissimilar friction stir welded joints of aluminium alloys”, Materials & Design 31 (9), 4184-4193 (2010).
 L.E. Svensson, L. Karlsson, H. Larsson, B. Karlsson, M. Fazzini, and J. Karlsson, “Microstructure and mechanical properties of friction stir welded aluminium alloys with special reference to AA 5083 and AA 6082”, Science & Technology of Welding & Joining 5 (5), 285-296 (2000).
 K. Ratnesh, I. Shukla, and P.K. Shah, “Comparative study of friction stir welding and tungsten inert gas welding process”, Indian J. Science and Technology 3 (6), CD-ROM (2010).
 K. Colligan, “Material flow behavior during friction stir welding of aluminium 7075”, Welding Research Supplement 1, 229-237 (1997).
 A. Squillace, A. De Fenzo, G. Giorleo, and F. Bellucci, “A comparison between FSW and TIG welding techniques: modifications of microstructure and pitting corrosion resistance in AA 2024-T3 butt joints”, J. Materials Processing Technology 152, 97-105 (2004).
 A. Cabello Muñoza, G. Rückert, B. Huneaua, X. Sauvageb, and S. Maryaa, “Comparison of TIG welded and friction stir welded Al-4.5Mg-0.26Sc alloy”, J. Materials Processing Technology 197, 337-343 (2008).
 N.T. Kumbhar and K. Bhanumurthy, “Friction stir welding of Al 5052 with Al 6061 alloys”, Hindawi Publishing Corporation J. Metallurgy ID 303756, 7 (2012).
 K. Mroczka, A. Wojcicka, and A. Pietras, “Characteristics of dissimilar FSW welds of aluminum alloys 2017A and 7075 on the basis of multiple layer research”, JMEPEG 22, 2698-2705 (2013).
 M. Ghosh, K. Kumar, S.V. Kailas, and A.K. Ray, “Optimization of friction stir welding parameters for dissimilar aluminum alloys”, Materials and Design 31, 3033-3037 (2010).
 D. Burford, Ch. Widener, and B. Tweedy, “Advances in friction stir welding for aerospace applications”, 6th AIAA Aviation Technology, Integration and Operations Conf. (ATIO) 25-27, CD-ROM (2006).