Investigating the Effect of SiC Nanoparticles on the Shear Strength of Friction Stir Lap Welded 7075 Aluminum Alloy

In this paper, the effect of including SiC nanoparticles in the weld zone on the maximum shear strength of friction stir lap welded 7075 aluminum alloy is investigated, both experimentally and numerically. This objective is carried out by studying the effects of rotational and transverse speeds, tilt angle, the shape of the tool and the penetration depth. The numerical investigation is based on developing an FE model by means of Deform and ABAQUS to simulate the welding procedure, which results are verified by the experimental findings. Experimental procedure is designed based on Taguchi method. The verification of the developed FE model shows that the simulation results are in proper agreement with the experimental findings. In general, including SiC nanoparticles in the weld zone can increase the maximum shear strength up to 24%, compared to the case of where the specimens are welded without SiC. Furthermore, applying the threaded tapered tool leads to higher shear strength in comparison with the squared shape tool, i.e., the strength of the specimens welded by threaded tapered tool are 4 to 5% higher without SiC inclusion and 4 to 7.5% higher with SiC, compared to the same case welded by squared tool. In addition, while the rotational speed has the highest influence on the findings, the tilt angle does not affect the results that much.