Solidification Microstructure Formation in Stainless Steels Additively Manufactured by Powder Bed Fusion

Abstract

Solidification microstructure formation in stai nless steels additively manufactured by powder bed fusion PBF has been reviewed, focusing on the characteristics owing to the unique solidification condition of the PBF process. The crystallographic orientation textures are controlled by using specially designed laser beam scanning strategies combined with appropriate beam power and beam scanning speed. Also, the rapid solidification with large temperature gradients has been found to give rise to extremely fine cellular structures associated with the microsegregation of solute atoms such as Cr and Mo. The hierarchical structures from nanometer to sub-millimeter scale are the key to the maximized potential of performance of stainless steels by the PBF. Studies on grain refinement and single crystal growth are also underway, focusing on the unique solidification condition.