Deformation and recrystallization of single crystal nickel-based superalloys during investment casting

A semi-quantitative, macroscopic, phenomenon-based, thermo-elastic-plastic model was developed to predict the final plastic strains of single crystal nickel-based superalloys by considering their orthotropic mechanical properties. Various cases were considered and simulated to investigate the basic factors that influence the final plasticity. Thermo-mechanical numerical analysis was conducted to predict the recrystallization sites of simplified cored rods, with the results in good agreement with the experimental results. These hollowed rods with thin walls showed an increased propensity for recrystallization. The geometric features, especially stress concentration sites, are more significant to the induced plasticity than the material's orientation or shell/core materials. This paper also attempts to provide useful suggestions, such as introducing filets, to avoid causing plastic strains during the casting process that induce recrystallization.