Near Single-Crystalline CMSX-4 Superalloy Builds with Laser-Directed Energy Deposition (L-DED) Using Model-Informed Experiments

Manufacturing of single-crystalline Ni-base superalloyNi-base superalloys blades is extremely complex due to the intricate geometry of the blade profile and cooling channels. Additive manufacturingAdditive manufacturing provides an excellent alternative to the classical Bridgman solidificationSolidification, as it significantly reduces the number of steps involved. However, since the solidificationSolidification conditions differ greatly, it is crucial to identify appropriate process parameters to ensure defect-free single-crystalline builds. In this paper, we present a complementary approach between experiments and numerical simulationsNumerical simulation of the melt pool shapes that enables the identification of the process parameter window for directional growth. Further, an incremental process optimization approach is developed that allows the gradual reduction of grains, creating conditions for epitaxialEpitaxial growth. Finally, it is revealed that the proposed strategy for achieving single-crystalSingle-crystal growth conditions leads naturally towards crack-free builds of rods with the CMSX-4CMSX-4 alloy.