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Abstract
A method for predicting the fastest possible homogenization treatment of the as-cast microstructure of nickel-based superalloys is presented and compared with experimental results for the single-crystal superalloy ERBO/1. The computational prediction method is based on phase-field simulations. Experimentally determined compositional fields of the as-cast microstructure from microprobe measurements are being used as input data. The software program MICRESS is employed to account for multicomponent diffusion, dissolution of the eutectic phases, nucleation, and growth of liquid phase (incipient melting). The optimization itself is performed using an iterative algorithm that increases the temperature in such a way that the microstructural state is always very close to the incipient melting limit. Maps are derived allowing describing the dissolution of primary γ/γ'-islands and the elimination of residual segregation with respect to temperature and time.