Solute redistribution and segregation in solidification processes

In this review paper, research on solute redistribution coefficients for equilibrium, near equilibrium and non-equilibrium solidification processes were first analyzed. Then, different models advanced since the 1950s for solute redistribution during the directional solidification process with a planar interface were summarized. The so-called second-order opposite diffusion compensation method (SODCM) presented by the author was described in detail. Thirdly, solute redistribution in the dendritic solidification process and the segregation were discussed. It is concluded that the problem can be described resulting phi(s)-w(L) functions. Among the different models, that obtained by the present author in 1994 was explained. Fourthly, the formation of macro-segregation mainly caused by liquid flow in the mushy zone is analyzed. A parameter about the driving force for the liquid flow is described. The parameter is considered to be the controlling parameter for the formation of macro-segregation. The relationship between the parameter and the compositions in steel is also given in the paper as an example. (C) 2001 Elsevier Science Ltd. All rights reserved.