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.

Automated summary

Controlling grain structure and avoiding stray grain (SG) formation is crucial in manufacturing nickel-based single crystal (SX) superalloy components using laser additive manufacturing. This study presents a new approach to inhibit SG formation by optimizing the substrate crystallographic orientation. A numerical model is also developed to predict SG formation in the molten pool by considering the combined effects of substrate orientation and equiaxed grain formation tendency. Both experimental and simulation results indicate that (001)/[110] and (01 root 3)/[100] substrate orientations can effectively suppress SG formation.