Prediction of casting structure in aluminum-base multi-component alloys using heterogeneous nucleation parameter

Heterogeneous nucleation rates in solidifying aluminum-base multi-component alloys (AC2A, AC2B and AC8C commercial alloys) were determined as the form of the nucleation parameter. Unidirectional solidification experiments were carried out using the multi-component alloys and the nucleation parameters were determined by simulating the macrostructure similar to the experimentally observed one with a PF-CA model, which is a model developed by coupling a cellular automaton (CA) method with a phase-field (PF) method. A conventional casting experiment for the multi-component alloys was carried out, and prediction of the macrostructure of the castings with the PF-CA model has been carried out using the determined nucleation parameters from the unidirectional solidification. In the case of the AC2A commercial alloy, the simulated macrostructure was in good agreement with the experimentally observed one. In the case of the AC2B commercial alloy, although the simulated macrostructure near the mold wall was different from the experimentally observed one, the size of inner equiaxed crystals was similar to that observed in the experiment. In the case of the AC8C commercial alloy, the simulated macrostructure was not similar to the experimentally observed one. The disagreement between the results of the experiment and simulation might be due to a multi-phase solidification manner in the AC8C alloy.