Stochastic modeling of dendritic microstructure of aluminum alloy

Abstract

Stochastic modeling was carried out for simulating the evolution of dendritic grains during the solidification process of aluminum alloy. The model includes time-dependent calculations for temperature distribution, solute redistribution in the liquid phases, curvature of the dendritic tip, and growth anisotropy. In the model, a shape function was proposed to represent the equiaxed dendritic shape and the growing grain. The nucleation process was calculated by continuous nucleation. However, the location and the crystallographic orientation are chosen randomly among all possible nucleation sites and the possible directions, respectively. A numerical algorithm based on the coordinate transformation approach was developed to explicitly track the sharp solid/liquid (S/L) interface. The microstructure simulation scheme was developed to model the grain formation. In order to verify the modeling results, sample castings were cast in sand and metal mold. Experimental and numerical results agreed well.

Keywords:

• stochastic modeling
• nucleation and grain growth
• shape function
• coordinate transformation method