Vacuum centrifugal investment casting of thin-walled IN713C superalloy turbine blades: melt filling, solidification behavior and fatigue performance

A novel vacuum centrifugal investment casting route was developed to fabricate thin-walled IN713C superalloy turbocharger turbines, aiming to overcome the limitations of coarse grains and casting defects typically observed in conventionally cast components. Combined numerical and experimental studies show that increasing centrifugal speed enables precise filling of 0.4 mm blades. Optimized parameters (750 rpm, 1450 °C pouring, 800 °C shell) reduce hub porosity by ∼50%, increase density from 7.855 to 7.893 g/cm3, and refine blade root grains from columnar to ∼650 μm equiaxed. Consequently, the turbines exhibit a 21.7 - 95.4% improvement in fatigue life at 650 °C. The improvement arises primarily from reduced shrinkage-porosity-induced crack initiation, while grain refinement and carbide homogenization further enhance resistance to fatigue crack propagation. This study provides a reliable process framework and practical basis for applying vacuum centrifugal investment casting to high-performance Ni-based superalloy components with complex thin-walled geometries.