Experimental Investigation Joining Al 5083 and High-density Polyethylen by Protrusion Friction Stir Spot Welding Containing Nanoparticles using Taguchi Method

One of the most important challenges of the Friction Stir Spot Welding (FSSW) process is the appearance of a void in the welded parts. This causes the stress to be stacked against the created void, and as a result, the mechanical properties would be reduced. To solve this problem in this research, the aluminum and polyethylene sheets are joined by means of H13 steel tools, protruding fixtures, and also three types of nanoparticles. Appending three types of Nano-particles, namely Al2O3, TiO2, SiO2, the constituent materials of Al 5083 and high-density polyethylene sheets have been prepared. To improve the mechanical properties of the welded samples, these three types of Nano-materials are integrated to the Stir Zone (SZ). In order to find the maximum strength of welded composite plates, the Design of Experiment (DOE) is performed using the Taguchi method. The Rotation Speed, Dwell Time, Tool d/ Protrusion d besides the type and percentage of Nano-material are chosen as input parameters. The maximum fracture force and the maximum strength are respectively as 2249 N and 4.13 MPa. Without using nanoparticles, a rupture is occurred in the tensile tests of polyethylene samples. Thus, the polyethylene samples capture more sediment by addition of nanoparticles, and the nanoparticles' deposition improves the mechanical properties of the Al/PE composite. Compared to the base material of pure aluminum and polyethylene, a nearly eightfold increment of the mechanical properties of the Al/PE composite sample is observed by addition of nanoparticles in the welding nugget. According to the S/N ratio analysis, the rotation speed of 2500 rpm, dwell time of 12 s, tool d/ protrusion d of 3 mm, Nano-material's type of Sio2 and percentage of 10% are considered as the optimum states.