Microstructure and Mechanical Properties of Friction Stir Welded AA2024-T3 Joints

This paper focuses on the examination of macrostructure and microstructure of friction–stir-welded AA2024-T3 joints. The tool rotation speed and the traverse speed, the most important process parameters of FSW, are evaluated through tensile strength test and microhardness test. The analysis of microstructure showed a zonal transition from the base material to a heat-affected zone; a thermo-mechanical affected zone and a nugget zone in the center of the weld with a grain sizes were different. From this investigation, it is found that the tensile strength and percentage elongation increase with the traverse speed decreasing, whereas it increases as tool rotation speed increases up to the 750 rpm and then decreases with further increase of tool rotation speed. As a result, increasing the tool rotational speed leads to the increase in hardness nugget zone than that in the thermo-mechanically affected zone and affected zone. The microhardness was strongly dependant on tool rotation speed and it increases with the increasing of this parameter from 600 to 750 rpm.