Fatigue and monotonic tensile behaviors of friction stir welded AA6061/SiC/20p-T1 composite joints at various tool rotation speeds

In this paper, fatigue and mechanical properties of the friction stir butt-welded AA6061/SiC/20p composites are investigated at varying tool rotation speeds. Thereby, the relationships between welding parameters and mechanical test results and also fatigue behavior are established. From the results, it is found that the joints at the lower tool rotation speed of 1000 rpm show superior mechanical properties in terms of the tensile strength by comparison with 1250 rpm and 1600 rpm. Additionally, the mean Vickers in the stir zone of joints decreases with the increasing tool rotation speed. The process results in a 93.29% maximum performance of fatigue strength at 1250 rpm. On the other hand, it has been found that the joints at 1600 rpm are more sensitive to cyclic loading than other welds. Micrographs of the fractured surfaces are found to be consistent with the findings of stress controlled fatigue tests.