Modelling of non-equilibrium solidification in ternary alloys: comparison of 1D, 2D, and 3D cellular automaton–finite difference simulations

摘要

A cellular automaton–finite difference (CAFD) computer model is presented that describes the solidification of multicomponent multiphase alloys at the microscopic level. The objective of the model is to enable the prediction of microsegregation patterns and the appearance of non-equilibrium constituents during non-equilibrium freezing. To support the development of the model, coupling with a thermodynamic software package, ThermoCalc, has been achieved to obtain accurate thermodynamic data for multicomponent alloys. The CAFD model has been used to generate evolving dendritic structures in two and three dimensions. A simple one-dimensional (1D) CAFD plate model, which assumes that adjacent dendrite arms are plates, has also been developed. Recently, experimental results of a study carried out on a directionally solidified Al–3.95Cu–0.8 Mg alloy (cooling rate of 0.378 K s-1) have been reported. In the present investigation, a comparison between 1D, 2D, and 3D simulations of microsegregation and these experimental results is made, with respect to the amounts of non-equilibrium constituents and solute profiles in the primary -Al phase, for the same alloy and solidification conditions.