Effects of solute and flow field on 3D dendritic growth of superalloys in melt convection

Abstract

Solute field, convection field and temperature field are important factors in determining the formation mechanism of solidification microstructure defects in superalloys. In the behavior of melt convective, different orientations of dendrites hinder the convective flow of the melt. And a special segregation channel may be formed between the dendrites to cause solidification defects. In this study, a numerical model for accurately calculating three-dimensional dendrite growth in superalloy melt convection is proposed. And a 27-point solute field discretization scheme is used to discretize the dendrite growth model in multi-physical field. Then, the model is solved by using the in-situ grid technique and SIMPLE algorithm. The results of numerical simulation are similar to those of LGK analysis and Oseen-Ivantsov solution, which verifies the practicability and effectiveness of the model algorithm to a certain extent. With the increase of undercooling, the effect of asymmetric growth of dendrite morphology decreases gradually, but with the increase of inlet velocity, the effect of asymmetric growth of dendrite morphology increases gradually.