3D STOCHASTIC MODELING OF EQUIAXED SOLIDIFICATION IN THE PRESENCE OF GRAIN MOVEMENT

A three-dimensional stochastic model of equiaxed solidification of eut ectic alloys in the presence of convection/sedimentation is proposed. Assuming uniform temperature, the heat balance is coupled to a microsc opic description of grain evolution. Grain location is chosen randomly within the solidifying volume. Grain evolution is followed by mapping the interface of each grain with a large number of elementary surface s. Each grain is fully described by its centre position, radius, and t he status of its elementary surfaces (in contact with liquid or not). Grain movement is modelled by changing centre coordinates; evolution o f the solid volume fraction is deduced by summing over all elementary surfaces which comprise the solid-liquid interface. A recursive method yields two-dimensional grain sections. Grain movements associated wit h convection and sedimentation are investigated, and their effects on the final grain structure, the solid-liquid interface, the impingement factor, and the cooling curve are shown.