Cell structure in steels induced by additive manufacturing

This review discusses the cell structure induced by additive manufacturing (AM) with a focus on stainless steel 316L and maraging steel 18Ni-300 produced by laser powder bed fusion. The microstructural characteristics of AM cell structure are described. The central role of AM cell structure in the process-microstructure-property-performance relationship of AM steels is demonstrated, in which the methodology of modifying AM cells and the strengthening mechanism by AM cells are critically reviewed. The limitations of the current research mainly lie in the reproducibility of microstructures and the solution to the strength-ductility trade-off of AM steels. Finally, suggestions for further studies are presented: to establish a fine-scale process-microstructure-property-performance relationship of AM steels and to print novel composite materials through microstructure design.