Simulation of Channel Segregation During Directional Solidification of In—75 wt pct Ga. Qualitative Comparison with In Situ Observations

Abstract

International audienceFreckles are common defects in industrial casting. They result from thermosolutal convection due to buoyancy forces generated from density variations in the liquid. The present paper proposes a numerical analysis for the formation of channel segregation using the three-dimensional (3D) cellular automaton (CA)—finite element (FE) model. The model integrates kinetics laws for the nucleation and growth of a microstructure with the solution of the conservation equations for the casting, while introducing an intermediate modeling scale for a direct representation of the envelope of the dendritic grains. Directional solidification of a cuboid cell is studied. Its geometry, the alloy chosen as well as the process parameters are inspired from experimental observations recently reported in the literature. Snapshots of the convective pattern, the solute distribution, and the morphology of the growth front are qualitatively compared. Similitudes are found when considering the coupled 3D CAFE simulations. Limitations of the model to reach direct simulation of the experiments are discussed

Three-dimensional cellular automaton-finite element modeling of solidification grain structures for arc-welding processes

“…with K c ¼ ÀV$n (11) and n ¼ Vj kVjk (12) where a g is the vector of the gravitational acceleration, K c is the local mean curvature of the liquid/gas interface defined by the unit outward normal vector of this interface, n, and g l=g is the liquid/gas surface tension. It should be noticed that the computation of the interfacial velocity vector is linked to the local viscosity through the solution of the momentum conservation.…”

Impact of solute flow during directional solidification of a Ni-based alloy: In-situ and real-time X-radiography

“…Moreover, the internal surface of the mold (orientation, roughness…) do have effects that are also not considered [10]. Therefore, there is a major interest in developing multiphysical numerical simulations [11] that must be validated with accurate and relevant experimental observations [12].…”

Temperature-based energy solver coupled with tabulated thermodynamic properties – Application to the prediction of macrosegregation in multicomponent alloys

“…The temperature-based method proved to be faster in computation time in all cases. Coupling with the prediction of grain structure is presently under development [27], considering the importance already demonstrated elsewhere [10], [17]. Besides, this article only presents tabulations used with the approximation of full equilibrium -or lever rule-for macrosegregation calculations.…”