Friction stir spot welding is a unique solid-state process for joining different metallic components in many
applications such as automotive industry. It is very widely used and being considered as a superior alternative to
conventional joining methods. The welding process parameters include the tool rotational speed, pin length,
shoulder width and dwell time. Optimum process parameters where identified in prior investigations that
produced the highest joint strength for this type pf alloys. This paper is a trial to validate these results and explain
the high strength of the welded joint through microstructural investigations. Optical microscopy, scanning
electron microscopy and Vicker's microhardness tests were used to analyze the welded joint. The investigation
validated the optimum process conditions in microstructural and hardness variations across the different zones of
the welded joint.