Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2011.1959.1965AwangM. AhmatI. M.HussainP. 1120111111Friction Stir Welding (FSW) is a solid-state joining process where a non-consumable, rotating tool is rotated at a constant speed and fed at a constant traverse rate into the joint line between two pieces of sheet or plate material, which are butted together. Whereas, Friction Stir Spot Welding (FSSW) is a derivative of FSW without lateral movement of the tool during the process. Two plates of aluminum alloy 2011 in the dimension of 10 mm thickness was joint welded by using FSW and 1 mm thickness of Aluminum alloy 1100 sheets was spot welded by using FSSW. The strength of the welds was tested using Universal Tensile Machine and the microstructure evolution was observed using optical microscope. Three different regions of FSW and FSSW welds were characterized whereas the strengths of the FSW and FSSW welds were compared to the parent metal.]]>Thomas, W.M., E.D. Nicholas, J.C. Needham, M.G. Murch, P. Temple-Smith and C.J. Dawes,19911991Yuh, J.C. and Q. Xinhai,19991999Badeshia, H.K.D.H., 20032003Mitlin, D., V. Radmilovic, T. Pan, J. Chen, Z. Feng and M.L. Santella,20064417996Pan, T.Y., A. Jouquin, D.E. Wilkosz, L. Reatherford, J.M. Nicholson, Z. Feng and M.L. Santella,20042004pp: 17Mishra, R.S. and M.W. Mahoney,20072007Colligan, K., I. Ucok, K. McTernan, P. Konkol and J.R. Pickens,20012001Davis, J.R.,1993Illustrated Edn.,pp: 784pp: 784