Effect of tool rotational speed on the mixed mode fracture strength of dissimilar friction stir welded aluminum alloys

The friction stir welding (FSW) process was introduced in 1991 by the UK Welding Institute known as TWI. In this method, no filler material is used to connect two metals, rather, this thermal friction is the result of a special rotating tool that is used for welding different parts. By rotating this cylindrical tool and sinking it into the line of connection between two metals, friction and disturbance are created, and at the same time, heat and pressure also rise in this place to prepare the conditions for the welding of two metals. During the last two decades, a large number of researches have been carried out to investigate the mechanical properties and microstructure of joints made from several similar and dissimilar alloys. Crack growth resistance of such joints under tensile, shear and mixed loading is an important design parameter to evaluate the lifetime of welded parts in friction stir welding. However, a literature review shows that there is limited research on combined mode I/II in FSW welding. Therefore, to fill this research gap in this research, tensile and fracture strength in dissimilar FSW welding of AA5083/AA5052 aluminum alloys are investigated experimentally. For this purpose, one of the efficient parameters as pin rotation speed, has been selected as welding variable parameter. After carrying out the welding by three different rotation speeds, the samples of tensile test and cracked mixed mode fracture tests are performed to determine the effect of considered parameter on the tensile and fracture strength of joint.