Influence of platform position on stray grain nucleation in Ni-based single-crystal dummy blade clusters

Stray grains are the most severe of solidification defects that occur in industrial single-crystal blade preparation process. In this study, a dummy cluster with different crystal orientations controlled by seeding method was prepared, and influence position circular platform (relative to sample furnace body) on stray grain nucleation investigated. Results show microstructure platforms could be divided into center, expansion, regions. The inside facing center is more prone formation than outside body. With an increase distance between bottom cluster, region expands, whereas expansion narrows. slightly aggravated misorientation. Finally, mechanism underlying clusters discussed based temperature evolution during directional solidification.