Dispersoid Refinement and Part Defect Optimization in Additively Manufactured Oxide‐Dispersion‐Strengthened Steels

Hard machinability of oxide‐dispersion‐strengthened (ODS) steels restricts their application in complex‐shaped components for nuclear engineering. Additive manufacturing (AM) offers a promising route to overcome such limitation. However, the nanoparticle (NP) densities achieved in AM‐fabricated ODS steels are still far from those obtained by conventional processing routes. This review aims to provide guidance for refining the NPs meanwhile balancing the part defects commonly encountered in ODS steels. The powder feedstock characteristics and their impacts on part defect formation during the AM process are summarized. Surface‐NPs‐decorated and gas atomization reaction‐synthesized powders result in fewer part defects induced by oxide addition. In particular, the review elaborates the NP evolution process in melt pool and review the NP refining methods. Powders with dissolved strengthening elements show greater potential for dispersoid refinement. Additionally, potential effects of NP on AM grain structures and the resulting as‐printed mechanical properties are reviewed. A promising direction for dispersoid refinement and defect control lies in powder structure design.