Microstructural evolutions and mechanical properties of friction stir welded AA2024-3

In the present work, the effect of rotating speed on the microstructural evolution and mechanical properties of AA2024-T3 subjected to friction stir welding (FSW) were studied. Four rotational speeds (400, 500, 630 and 800rpm) at a constant traverse speed (32mm/min) were employed. The results show that the generated temperature gradient across the nugget zone resulted in microstructural changes in terms of size and distribution of precipitates. Besides, increasing in rotation speed from 400rpm to 800rpm caused about 10% increase in both tensile and yield strength. According to the results of bending tests, an increase in the rotation speed led to a decrease in the bending angle of FSWed specimens. The W-shaped hardness profile was observed for all rotation speeds. However, the hardness profile obtained for 400, 500 and 630rpm exhibited a lower hardness in base material compared to that of nugget zone.