Optimization of Post-Weld Heat Treatment Parameters for Improving Tensile Strength of Dissimilar AA6061–AA7075 Friction Stir Welded Joints Using the Taguchi Method

Somchat Sonasang; Panuwat  Thosa; Thanatep  Phatungthane

Authors

Somchat Sonasang Nakhon Phanom University, Thailand
Panuwat Thosa Nakhon Phanom University, Thailand
Thanatep Phatungthane Nakhon Phanom University, Thailand

Keywords:

Friction Stir Welding, Post-Weld Heat Treatment, AA6061, AA7075, Taguchi Method, Mechanical Properties, Tensile Optimization

Abstract

This research presents a novel approach to optimizing post-weld heat treatment (PWHT) parameters for dissimilar friction stir welded joints between AA6061 and AA7075 aluminum alloys. Unlike prior studies that often overlook multi-variable interactions, this study employs a Taguchi L9 design of experiments to systematically investigate the combined effects of solution treatment and aging conditions. The optimal PWHT configuration — solutionizing at 480 °C followed by aging at 180 °C for 6 hours — achieved a peak tensile strength of 307.38 MPa. Elongation performance was strongly influenced by aging duration, with extended times promoting superior ductility. Statistical analysis using ANOVA confirmed aging time as the most significant factor. The novelty of this work lies in the integrated experimental–statistical methodology and its application to dissimilar aluminum joints, providing a robust strategy for tailoring mechanical properties through customized thermal cycles. These findings offer practical insights for engineering applications requiring high-performance welded structures.

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