According to a 2025 review in Science and Technology of Welding and Joining, friction stir welding (FSW) has become a mature solid-state joining process for aluminum alloys, offering defect-free joints with superior mechanical properties compared to fusion welding.
FSW eliminates common fusion-weld defects such as porosity, hot cracking, and distortion. The process uses a rotating tool that generates frictional heat and plastic deformation, creating a fine-grained, recrystallized weld zone. For heat-treatable alloys like 6061 and 7075, FSW retains up to 90% of base metal strength, whereas fusion welding often drops below 70%.
Key industrial applications include automotive battery trays, aerospace fuselage panels, and ship decking. The process is also being adapted for high-strength steels and titanium alloys, though tool wear remains a challenge.
For welding engineers, FSW represents a shift from consumable-driven to tool-driven joining. Qualification requires new parameters and mechanical testing protocols, but the payoff in quality and repeatability is substantial.
How is your organization adopting solid-state welding for lightweight structures?
Source: Science and Technology of Welding and Joining, 2025