An experimental analysis and optimization of process parameters of AA6061 and AA7075 welded joint by TIG plus FSP welding using RSM

The empirical relationships were developed to predict the tensile strength, percentage elongation, micro-hardness and residual stress of the TIG+FSP welded joint of AA6061 and AA7075 at a 95% confidence level. The developed models show that the tool rotational speed and tilt angle are the dominating parameters as compare to others. The decrease in traverse speed and increase the tool rotational speed lead to the increase in heat input to TIG+FSP welded joint. The confidence interval has shown that tensile strength and hardness increased with increasing tool rotation, whereas residual stress decreased with increasing tool rotation. The minimum compressive residual stress of 18 MPa, maximum tensile strength (255 MPa), and hardness (105 HV) were located at the nugget zone of the TIG+FSP weldment at tool rotation 1300 rpm, traverse speed 45 mm/min with tilt angle 1 degrees. The optimized value of tensile strength, percentage elongation, micro-hardness at nugget zone, and residual stress at nugget zone is 216.52 MPa, 23.65%, 89.65 HV, and 43.74 MPa respectively, whereas the optimized input process parameters tool rotation, traverse speed, and tilt angle are 1123.53 rpm, 50.37 mm/min and 0.1424(0) respectively.