Comparison of CA Model for Dendritic Solidification with Scheil and Equilibrium Models

A. Zyska, K. Boroń,, S. Domin Częstochowa University of Technology, Faculty of Production Engineering and Materials Technology, Institute of Metallurgy and Metal Technology, al. Armii Krajowej 19, 42-200 Częstochowa, Poland

Received: August 22, 2019; revised version February 6, 2020; in final form February 11, 2020

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A mathematical model based on the technique of a cellular automaton to simulate the dendritic solidification of two-component alloys is presented. The results of numerical calculations were compared with the predictions of the Scheil and equilibrium analytic models. Comparative analysis was carried out on the example of Al-3wt% Mg alloy. The differences between the models were revealed by determining the profiles of the solid phase Mg concentration for the three cooling rates 1, 25, and 70 K/s, assuming no diffusion and limited diffusivity in the solid state. It has been found that the degree of microsegregation of the element in the test alloy is mainly controlled by the cooling rate, and the effects of back diffusion are detectable only at low intensity of heat dissipation. Moreover, the developed 2D cellular automaton model allows simulation of the evolution of dendritic structures and determination of solid compositions' variations for different solidification conditions in the range from predictions of the equilibrium model to the predictions of the Scheil model.

DOI:10.12693/APhysPolA.137.1046 topics: CA model, solidification, Al-Mg alloy, microsegregation\\vs*{10pt}