Controlling solute trapping and solute drag in a phase-field model

Published

March 16, 2023

Author(s)

Arnab Mukherjee, James A. Warren

Abstract

The finite solid-liquid interface width in phase-field models results in non-equilibrium effects, including solute trapping. Prior phase field modeling has shown that this extra degree of freedom, when compared to sharp-interface models, results in solute trapping that is well captured when realistic parameters, such as interface width, are employed. However, increasing the interface width, which is desirable for computational reasons, leads to artificially enhanced trapping thus making it difficult to model departure from equilibrium quantitatively. In the present work, we develop a phase-field model with independent kinetic equations for the solid and liquid phases. Separate kinetic equations for the phase concentrations obviate the assumption of local equilibrium, as is done in previous works. Non-equilibrium effects such as solute trapping, drag and interface kinetics can be introduced in a controlled manner in the present model. In addition, the model parameters can be tuned to obtain "experimentally-relevant" trapping while using significantly larger interface widths than prior efforts. A comparison with these other phase-field models suggest that interface width of about two to seven times larger than current best-in-class models can be employed depending upon the material system at hand leading to a speed-up by a factor of W(d+2), where, W and d denotes the interface width and dimension, respectively. For instance, an increase of the interface width by a factor of two expedites the computation by 16 and 32 times in two and three dimensions respectively. Finally the capacity to model non-equilibrium phenomenon is demonstrated by simulating oscillatory instability leading to the formation of solute bands.

Citation

Acta Materialia

Pub Type

Journals

Keywords

Phase-filed

Citation

Mukherjee, A. and Warren, J. (2023), Controlling solute trapping and solute drag in a phase-field model, Acta Materialia (Accessed April 29, 2024)