Evolution of sliver morphology in large-sized single-crystal superalloy blades

The production of single-crystal superalloy blades seeks to eliminate grain boundary defects that compromise mechanical properties at elevated temperatures. At present, there is little research on slivers which introduced the grain boundaries to single-crystal blades. This study examines the growth mechanisms of slivers through a combination of experimental analysis and cellular automaton (CA) simulations. The experimental results reveal that the morphology of slivers in single-crystal blades can be categorized into three types: fixed-width, gradually increasing width, and gradually disappearing. The variation in sliver morphology is not attributable to competitive dendritic growth, as the misorientation angle between slivers and the matrix remains consistently small. Furthermore, the simulation results demonstrate that the blade geometry can either obstruct or facilitate dendritic growth, which in turn drives the morphological evolution of slivers.