Friction stir welding (FSW) is a solid-state welding process that is used for fabricating high-quality aluminum
weldments. In this study, FSW is used to weld aluminum alloy AA6063 plates. Different combinations of FSW
conditions were used, and the generated welds were tested for toughness and microstructural grain size, in addition to
macrostructure evaluation. Factorial design of experiment approach was used to investigate the significance of the FSW
factors on the material properties of the joints. Moreover, response surface methodology (RSM) was used to optimize
the toughness and grain size response and the optimal FSW conditions were determined. The results revealed that both
tool rotational and traverse speeds as well as experiment factors have a great influence on the material properties. All
interactions between experiments factors are significant except for the welding speed and temperature interaction in
impact test.