Acta Metallurgica Sinica (English Letters) ›› 2019, Vol. 32 ›› Issue (11): 1396-1406.DOI: 10.1007/s40195-019-00897-0

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Numerical Simulation of Macrosegregation Caused by Thermal-Solutal Convection and Solidification Shrinkage Using ALE Model

Kang-Xin Chen1, Hou-Fa Shen1()   

  1. 1 Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, School of Materials Science and Engineering, Tsinghua University,Beijing 100084, China
  • Received:2018-12-05 Revised:2019-03-19 Online:2019-11-10 Published:2019-11-10

Abstract:

Solidification shrinkage has been recognized as an important factor for macrosegregation formation. An arbitrary Lagrangian-Eulerian (ALE) model is constructed to predict the macrosegregation caused by thermal-solutal convection and solidification shrinkage. A novel mesh update algorithm is developed to account for the domain change induced by solidification shrinkage. The velocity-pressure coupling between the non-homogenous mass conservation equation and momentum equation is addressed by a modified pressure correction method. The governing equations are solved by the streamline-upwind/Petrov-Galerkin-stabilized finite element algorithm. The application of the model to the Pb-19.2 wt%Sn alloy solidification problem is considered. The inverse segregation is successfully predicted, and reasonable agreement with the literature results is obtained. Thus, the ALE model is established to be a highly effective tool for predicting the macrosegregation caused by solidification shrinkage and thermal-solutal convection. Finally, the effect of solidification shrinkage is analyzed. The results demonstrate that solidification shrinkage delays the advance of the solidification front and intensifies the segregation.

Key words: Macrosegregation, Solidification shrinkage, Finite element method, Arbitrary Lagrangian-Eulerian (ALE)