A multiphase model is proposed to predict compositional and structural evolutions in dendritic alloy solidification. The model accounts for the transport phenomena occurring on the macroscopic (system) scale, as well as the grain nucleation and growth over various microscopic length scales. The present model generalizes a previous multi-scale/-phase model (Metall. Trans., Vol.24A, pp.2787-2802, 1993) by including liquid melt convection and solid phase transport. The macroscopic transport equations for the solid, and the interdendritic and extradendritic liquid phases are derived using the volume averaging technique. The resulting model equations are supplemented by constitutive relations for the interfacial transfer terms. Finally, the model is applied to investigate equiaxed dendritic solidification of an Al-4wt% Cu alloy in a rectangular cavity. For the first time, quantitative results for the dendritic microstructure evolution in the presence of melt convection and solid movement are obtained. The effects of crystal sedimentation on macrosegregation as well as the grain size distribution are illustrated.
|Original language||English (US)|
|Number of pages||21|
|Journal||American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD|
|State||Published - 1994|
All Science Journal Classification (ASJC) codes
- Mechanical Engineering
- Fluid Flow and Transfer Processes