Title: Influence of different pin profiles on the evaluation of interfacial microstructure and mechanical properties of Ti/Al by FSW process

Authors: A. Tamilarasan

Addresses: Department of Mechanical Engineering, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, SIMATS, Chennai, 602105, India

Abstract: This study employs friction stir welding to join dissimilar aluminium and titanium alloys using various pin profiles: straight cylindrical, threaded tapered cylindrical, straight hexagon, tapered hexagon, and straight threaded cylindrical. Welding parameters include rotational speeds of 250-450 rpm, 35 mm/min welding speed, and 3 mm axial feed. SEM analysis reveals defect-free welds at the Ti/Al interface with the straight hexagon tool at higher rotational speeds. XRD confirms brittle α-phase TiAl and ductile β-phase TiAl3 intermetallic compounds (IMCs) at the interface. Maximum micro hardness occurs near the stir zone due to IMC formation using the straight hexagon tool at 350 rpm. This sustainable, low-energy welding process enhances resource efficiency and promotes sustainable industrialisation by enabling lightweight, durable hybrid structures for aerospace and automotive applications, reducing material waste and fossil fuel dependency.

Keywords: friction stir welding; dissimilar materials; interfacial microstructure; Vickers micro hardness; sustainable industrialisation; resource efficiency; clean technologies; innovation; sustainable production.

DOI: 10.1504/IJCMSSE.2026.152498

International Journal of Computational Materials Science and Surface Engineering, 2026 Vol.12 No.3, pp.222 - 248

Received: 14 Aug 2024
Accepted: 28 Jul 2025
Published online: 24 Mar 2026 *

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