| Abstract Scope |
Additive Friction Stir Deposition (AFSD) is a rapidly advancing solid-state additive manufacturing technology for the production, repair, and enhancement of metallic components. By avoiding bulk melting, AFSD minimizes solidification-related defects, reduces residual stresses, and promotes refined microstructures with strong mechanical performance. This invited state-of-the-art review summarizes the evolution, capabilities, and emerging directions of AFSD and related friction-based additive variants. Key fundamentals, including heat generation, material flow, bonding mechanisms, tool design, and the influence of processing parameters on deposition quality, will be reviewed. Recent advances in microstructure control and mechanical performance will be highlighted. The review will also examine how AFSD can help shorten conventional forging and casting supply chains through near-net-shape manufacturing, rapid repair, and improved material utilization. In addition, the latest AFSD developments and industrial demonstrations will be presented. Finally, remaining technical barriers, challenges to industrial adoption, and future research opportunities will be identified for both researchers and industry |