Design Optimization and Performance Analysis of TiO₂-Reinforced Dissimilar AA5083–AA6063 Friction Stir Welded Joints Using Taguchi Method

Abstract

This study investigates the design optimization of TiO₂-reinforced dissimilar AA5083–AA6063 friction stir welded joints using the Taguchi method. Tool rotational speed, welding travel speed, and TiO₂ insertion depth were evaluated through an L9 orthogonal array, with tensile strength and hardness as response variables. The results show that tensile strength is mainly controlled by rotational speed, achieving a maximum value of 218.40 MPa at 900 rpm, 40 mm/min, and 3 mm TiO₂ depth, whereas hardness is primarily influenced by TiO₂ insertion depth, reaching 110.23 HV. Taguchi prediction and confirmation tests revealed errors below 2%, confirming result reliability. Microstructural and fracture analyses indicated effective material mixing and predominantly ductile fracture behavior. These findings demonstrate that distinct parameters govern tensile and hardness responses, providing useful guidance for parameter selection in EV and aerospace applications.