Multiscale modeling of equiaxed dendritic solidification of Al-Cu at constant cooling rate
Thursday, June 22, 2023, 3:00 PM - 3:20 PM
Max Bell Theatre
Ahmed Kaci Boukellal

To provide quantitative predictions, multiscale models of dendritic solidification (e.g., GEM, DNN, CAFE) need to be validated and require model parameters, which can be calculated by phase-field simulations. We report on a multiscale modeling of dendritic solidification in samples that are cooled homogeneously at a constant rate. We consider three Al-Cu alloys and samples from thin to bulk thickness. We investigate how the alloy composition, the distance between the equiaxed dendrites and the sample thickness influence the growth velocity and the radii of curvature of the primary tips. To this aim, we extend the prior study of three-dimensional phase-field simulations in thin samples (3DPFTS) [Boukellal et al. Materialia 1 (2018) 62-69] with additional simulations for different values of the sample thickness. From there on, we calculate the tip selection parameter based on the microsolvability theory. We show that the tip selection parameter remains almost constant during the free growth regime, despite the time variation of the tip supersaturation. We further quantify the dependence of the selection parameter on the sample thickness. The extracted tip selection parameters are then used as inputs for three-dimensional grain envelope model (GEM) simulations and the GEM results are compared quantitatively to the 3DPFTS ones.

Moderated by: Andreas Ludwig / Alain Jacot