Additive friction stir deposition of aluminum alloys: A critical review

Additive friction stir deposition (AFSD) enables near-net shape fabrication through layer-by-layer material deposition, depositing feedstock via frictional heat and plastic deformation for applications ranging from component manufacturing to repair. Given aluminum alloys’ favorable strength-to-density ratio and the challenges associated with fusion-based additive manufacturing of aluminum alloys, AFSD has emerged as a solid-state additive manufacturing method that overcomes fusion-based limitations of feedstock and atmospheric control. This review synthesizes the most recent published aluminum alloy AFSD research, examining the relationship between process parameters, microstructural evolution, and mechanical properties. Particularly, we focus on the relationships between process parameters and thermal distribution, thermal cycles on recrystallization and phase transformations, and their resulting influence on hardness, tensile properties, fatigue life, and corrosion resistance. This review also explores AFSD’s applications in recycling, repair, and composites, providing a comprehensive assessment of AFSD of aluminum alloys. Finally, this review presents the current technical challenges and limitations of AFSD and makes recommendations for future research directions.