A quantitative comparison between pseudo-binary and multi-component phase field models

We present a benchmark analysis to compare three different phase-field models for multi-component alloy solidification. This analysis is carried out between, two pseudo-binary approaches and one multi-component approach, with respect to solidification of a quaternary iron-containing Ti alloy. The first pseudo-binary PF model is a common approach based on the model of Karma et al. (Echebarria et al., 2004), while the second pseudo-binary PF model and the multi-component model are implemented based on the grand potential model of Provatas et al. (Shampur, 2017). A very good similarity in microstructure is achieved between the three phase field models during both isothermal and directional solidification. The two grand potential models also show an excellent agreement in solute segregation predictions, and they are able to predict both positively segregating and negatively segregating elements. Finally, the influence of solidification rate on the microstructure is also studied, with the results matching analytical predictions. The results demonstrate the usefulness of different PF modeling approaches, and highlight cases where a full multi-component model is needed.