Local x-ray diffraction analysis of the structure of dendrites in single-crystal nickel-base superalloys

摘要

The structure of the dendrites in the single-crystal nickel-base superalloys SC16, SRR99 and CMSX4 with different refractory element levels (Mo + Ta + W + Re) has been investigated by local X-ray diffraction. A special technique was used to improve the spatial resolution of the X-ray diffraction And to enable the precise control of the X-ray spot position within the dendritic structure. A significant Change of the γ/γ'-lattice misfit was found within the dendrite in the superalloys with higher refractory Element levels SRR99 and CMSX4. The observed misfit change is based on the change of the γ-lattice Parameter due to segregation of W and Re.