Large-scale simulation of dendrite growth in directional solidification castings

Abstract

In this study, the growth and distribution of directional solidification (DS) dendrites in entire cross‐sections of DS superalloy castings are simulated based on a modified shape function dendritic (MSFD) model coupled with the cellular automaton‐finite difference (CA‐FD) method. The macro‐thermal transfer and columnar grain growth are calculated using CA‐FD with a macro time‐step, and then, the original and boundary conditions for the dendrite‐growth simulation are determined via the interpolation of the macro temperature and the projection of the 3D preferential grain orientation using a matrix, M. The dendrite growth calculation cyclically proceeds based on the MSFD model. It is used to predict the growth of hundreds of dendrites throughout the cross‐section of a DS casting by considering the macro‐solidification parameters. The MSFD model is further applied to predict the competitive growth of DS dendrites and their distribution in the cross‐sections of a spiral selector and a fake single crystal turbine blade. The results of the simulation correlate with the results of the DS experiment. Hence, the modified model coupled with the macro‐simulation models can be used to predict the morphology and distribution of DS dendrites with respect to large‐scale castings produced by the DS process.