Friction Stir Spot Welding and Characterization of Bulk Aluminum Alloy 6061 Synthesized Using Powder Metallurgical Route

Abstract

Powder metallurgy (PM) is a manufacturing approach that enables the production of complex shapes with minimal waste. This approach allows for creating intricate and readily deployable components, often surpassing the capabilities of traditional casting and metal forming techniques. The present study explores the feasibility of employing friction stir spot welding (FSSW) to join aluminum alloy 6061 (AA6061) components fabricated using the PM route. The research involves fabricating AA6061 samples employing the PM process. The sintering process involved induction heating at 530–550°C, followed by hot forging, ensuring optimal densification. FSSW was applied to both PM-processed and conventionally wrought AA6061 samples using three welding parameters. Comparative evaluations focused on the resulting welds’ microstructural characteristics and mechanical properties. Microstructural analysis revealed that PM-fabricated samples exhibited finer grain structures and superior hardness within the weld zones than their wrought counterparts. Furthermore, the thermomechanically affected zone (TMAZ) was narrower in PM-processed joints, indicating enhanced mechanical properties and a more uniform microstructure. The hardness values witnessed in the FSSW of the PM-processed Al 6061 point to the formation of superior-quality joints when compared to FSSW-welded sections of sheets produced through conventional means. This study highlights the potential of PM-fabricated AA6061 for advanced welding applications, demonstrating notable improvements in microstructural refinement and joint quality, integrating PM techniques with advanced welding processes to overcome traditional manufacturing limitations.