Effect of Tool Tilt Angle on Metallurgical and Mechanical Properties of Friction Stir Welded AA6063-T6 Aluminium Alloy

DOI

10.2991/978-94-6239-750-7_4How to use a DOI?

Keywords

FSW; Tilt Angle; XRD; FESEM; FCGR

Abstract

This study investigates the effect of tool tilt angle on the mechanical and metallurgical behavior of friction stir welded (FSW) AA6063-T6 aluminium alloy plates. Welding was performed at tilt angles ranging from 1° to 2.5° in increments of 0.5°, while maintaining all other process parameters constant. Visual and macrostructural examination indicated that weld morphology and flash formation were strongly influenced by the tilt angle, with the 1.5° condition producing the most uniform, defect-free weld surface. Optical microscopy revealed characteristic microstructural variations across different weld zones, including significant grain refinement in the Stir Zone (SZ), elongated grains in the Thermo-Mechanically Affected Zone (TMAZ), and grain coarsening in the Heat-Affected Zone (HAZ). X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) confirmed the presence of the aluminium matrix along with secondary intermetallic phases such as Mg₂Si and AlFeSi, particularly within the SZ due to intense thermal exposure and dynamic recrystallization. Mechanical characterization demonstrated a strong correlation between tilt angle and joint performance. The 1.5° sample exhibited the highest tensile strength of 175 MPa, corresponding to 72.6% of the base metal strength, along with superior yield strength and elongation compared with other conditions. Vickers microhardness analysis showed maximum hardness in the SZ and minimum hardness in the HAZ, consistent with observed microstructural changes. Fatigue crack growth rate (FCGR) testing further showed improved fatigue resistance for the 1.5° sample, surviving up to 50,000 cycles before critical crack propagation. FESEM fractography confirmed predominantly ductile fracture behavior, establishing 1.5° as the optimum tilt angle for high-quality FSW joints.

Copyright

© 2026 The Author(s)

Open Access

Open Access This chapter is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

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TY  - CONF
AU  - Gautam Kunal
AU  - Harish Kumar Arya
AU  - A. S. Shahi
AU  - Ravindra K. Saxena
AU  - Deepti Jaiswal
PY  - 2026
DA  - 2026/08/31
TI  - Effect of Tool Tilt Angle on Metallurgical and Mechanical Properties of Friction Stir Welded AA6063-T6 Aluminium Alloy
BT  - Proceedings of the International Conference on Advanced Design, Manufacturing, and Sustainable Energy Systems (ICADMSES 2026)
PB  - Atlantis Press
SP  - 27
EP  - 46
SN  - 2589-4943
UR  - https://doi.org/10.2991/978-94-6239-750-7_4
DO  - 10.2991/978-94-6239-750-7_4
ID  - Kunal2026
ER  -