Crystal growth for different substrate orientations during laser directed solidification of single crystal superalloys

Controlling the grain structure while avoiding the stray grain (SG) formation is the key to fabricate the nickel-based single crystal (SX) superalloy components during laser additive manufacturing. In this study, a new approach is developed to inhibit SG formation by the selection of optimizing the substrate crystallographic orientation. Besides, a numerical model of combined substrate orientation with the tendency of equiaxed grain formation during epitaxial growth processing is developed to predict the SG formation in the molten pool. Combining the results from both experiments and simulations, results indicate that (001)/ [110] and (01 root 3)/[100] substrate orientation could suppress the formation of SGs effectively. (c) 2023 Published by Elsevier B.V.