Review on Field‐assisted Additive Manufacturing of Stainless Steels

Field‐assisted additive manufacturing (FAAM) represents a transformative advancement beyond conventional layer‐by‐layer deposition by employing external energy fields to actively regulate the fabrication process. This review summarizes the application of magnetic, thermal, acoustic, deformation, and multifield strategies to overcome intrinsic challenges in the additive manufacturing (AM) of stainless steels, including coarse columnar grain structures, porosity, and high residual stresses. The fundamental mechanisms underlying FAAM are systematically elucidated: magnetic and thermal fields generate Lorentz forces that enhance melt‐pool convection; acoustic fields induce ultrasonic cavitation and acoustic streaming to fragment dendrites; and deformation fields, such as in situ rolling or peening, impose severe plastic strain to drive dynamic recrystallization. Multifield approaches integrate these mechanisms to achieve synergistic microstructural control. Collectively, these interventions promote significant grain refinement, facilitate the columnar‐to‐equiaxed grain transition, suppress defect formation, and enhance mechanical properties. Reported results demonstrate grain size reductions of up to 70% and strength improvements of approximately 10%–15% through external field assistance during AM. Overall, this review highlights FAAM as a powerful strategy for producing high‐performance stainless‐steel components with superior microstructural control and enhanced overall performance, enabling the fabrication of next‐generation, high‐integrity components for aerospace, biomedical, and energy applications.