The performance in hydro-electric turbines requires understanding of how process parameters and chemistry selection affect solidification microstructure. The aim of this study is to provide a quantitative phase-field formulation for process-microstructure relationships as part of a larger collaboration that seeks to model stainless steels through the joint-cooperation of several multi-scale modeling techniques. We have developed phase-field models to simulate austenitic stainless steel solidification under experimental thermal histories. To this end we look at both pseudo-binary approximations for numerical efficiency and multi-component models to capture more complex dilution effects. The pseudo-binary formulation is underpinned by the alloying element equivalent value, a metallurgical tool used to analyze the microstructural impact of “minor” alloying elements in stainless steels, the multi-component mode utilizes full thermodynamic data fit to the model. For model validation we develop thin wall casting experiments to measure the thermal history and chemistry controlled microstructure. The models incorporate a thermodynamic parameterization and are linked to a thermal-phase transformation model which represents the experimentally measured thermal history. The results display a good agreement with the primary branch spacing and cellular to dendritic transition of the casting experiments. These models and software provide the basis for future expansion to include more complex microstructures.

Moderated by: Andreas Ludwig / Alain Jacot