Optimization of the Homogenization Heat Treatment of Nickel-Based Superalloys Based on Phase-Field Simulations: Numerical Methods and Experimental Validation
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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.
KeywordsSolvus Temperature Solution Heat Treatment Residual Segregation Process Window Single Crystal Superalloy
This work has been funded by the German Science Foundation (DFG) in the framework of the Collaborative Research Center/Transregio 103 (projects B1 and Z01). Support of Sabine Michel with the microprobe measurements is gratefully acknowledged. Bernd Böttger (access e.V., Aachen, Germany) is acknowledged for very helpful comments and suggestions regarding the phase-field simulations.
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