Effect of thickness on microstructure of thin-walled nickel-based single-crystal superalloy castings

With increasing turbine inlet temperatures in aero-engines, the demand for temperature -resistant turbine blades has led to the widespread use of nickel -based single crystal superalloys. These alloys, known for their exceptional performance in high -temperature and high -stress environments, incorporate advanced cooling structures like lamilloy and double wall cooling to enhance temperature tolerance. As the development of aviation technology, thin -walled structures are widely used in turbine blades of aero-engines. However, the adoption of ultra -thin wall structures, particularly in lamilloy turbine blades with thicknesses of 0.5 mm or less, presents a significant manufacturing challenge and will cause the degradation of mechanical properties. This study delves into the growth and evolution of dendrites in the nickel -based single -crystal superalloy DD403, exploring thin -walled specimens with varying thicknesses during directional solidification. Findings reveal that decreasing wall thickness correlates with a reduction in average primary dendrite arm spacing, smaller gamma ' precipitates sizes within the dendrite core and interdendritic regions, and reduced microsegregation levels of Al, Ti, Co and W. These insights contribute to optimizing thin -walled turbine blade performance in aero-engines applications.