Process parameter effects on solidification behavior of the superalloy during investment casting

Abstract

ABSTRACTThe dependencies of solidification parameters of complex castings on microstructure at a microscopic scale were investigated by numerical simulation combined with physical simulation. A novel high-throughput experiment is proposed to establish the relationship of solidification-microstructure and accelerate finding the optimum casting process parameters. The results show that when the temperature gradient (G) exists, the morphology of the microstructure of the K4169 is influenced by the G/V value. The permeability of the alloy in the mushy zone can be obtained by the ratio of λ1/λ2 with a fluctuation value in the range of 1.57 ~ 3.58. It turns out that the secondary dendrite arms spacing (SDAS) is more responsive to the change of solidification parameters than the primary dendrite arms spacing (PDAS). The effects of G and V on λ1 and λ2 are further discussed as well. Additionally, through analysis of the experimental data, quantitative formulas for the primary/secondary dendrites and the grain size are obtained to characterize the microstructure, which is beneficial to the guidance of all relevant solidification processes. The novel high-throughput method can be applied to all kinds of casting studies for time-saving, cost reduction and efficiency enhancement.