Effect of Tool Pin Geometry on the Mechanical Properties of Friction Stir Welded AA5083 composites

This research examined three distinct tool pin geometries of friction stir weld of AA 5083-T6 to determine the optimal shape for final weld characteristics. The tool traverse speed and tool rotational speed were considered as input process factors. A hybrid methodology combining Multi-Objective Optimization on Basis of Ratio Analysis with Entropy technique was presented to achieve optimal values of parameters that concurrently enhance yield strength, ultimate tensile strength, hardness, and elongation. A comparison of the optimum outcomes for all tool geometries indicates that the Taper threaded (TT) tool exhibits superior qualities (YS-142 MPa, UTS-271 MPa, hardness-87 HV0.1, percentage elongation-16.92%) compared to the other two tools. For TT, enhancements of 22.68% and 11.45% at UTS were noted in comparison to cylindrical threaded (CT) tool and Taper (T) tools. The Taper threaded tool exhibits the maximum torque, X-force, and Z-force when evaluated against other tools under optimal parameters. An enhancement of 16.07% and 2.37% at torque values is observed for the Taper threaded tool in comparison to the cylindrical threaded tool and T tool. Fluctuation at Z-force were observed with the cylindrical threaded tool. The distribution of X-force was relatively more uniform and stable for Taper threaded. A greater degree of X-force variation was noted for Taper tool. The coefficients of friction for T, Taper threaded, and cylindrical threaded tool are 0.242, 0.227, and 0.370, respectively. Confirmation tests were conducted to validate optimized parameters for all instruments, which were confirmed to be within acceptable limits. Moreover, enhanced force and torque performance was achieved using the tapered threaded tool.