Abstract: As a novel solid-state additive manufacturing technology, Additive friction stir deposition (AFSD) has attracted extensive research attention due to its ability to form microstructures similar to forging. Currently, research efforts have focused on process mechanisms, process features, and applications. In terms of process mechanism, the material flow mechanism between the transition and deposition zones, heat generation and transfer mechanism, microstructure evolution mechanism, and the interaction mechanism between process parameters, material flow, and thermal field evolution in the AFSD process have been revealed. In terms of process characteristics, research has found that AFSD exhibits macroscopic features such as solid-state, near-net shaping, and interface mixing, as well as refined and equiaxed microstructure features, which significantly affect the mechanical properties of AFSD specimens in terms of hardness and tensile strength. In terms of applications, AFSD has demonstrated extensive potential in the fields of additive manufacturing, coating and composite material manufacturing, and repair, and is applicable to a range of metal materials. Considering the research progress in process mechanisms, process features, and applications, it is apparent that the exploration of AFSD is still in its early stages, and its high efficiency, high quality, and low energy consumption additive characteristics endow it with enormous development potential.

Key words: additive manufacturing, solid phase additive manufacturing, additive friction stir deposition, process mechanism, process characteristics, applications