Numerical modelling of columnar to equiaxed transition - application to microgravity experiments

International audienceA multiphase model based on statistical averaging is applied for simulation of the columnar-to-equiaxed transition (CET) during solidification of Al-7wt-%Si non-refined and refined alloys under microgravity conditions. Simulations are performed in one-dimensional approximation, taking into account real boundary conditions through thermal sources in the energy equation. The comparison between calculated positions of CET and measured positions in the MACE experiments is made. An agreement is obtained when using values of the nucleation undercooling of Delta T-Ne=6 K and Delta T-Ne=5 K for non-refined and refined alloy, respectively