Simulation of primary dendrite spacing in unidirectionally solidified alloy

A two-dimensional cellular automaton model for simulation of dendritic growth during solidification of binary alloy was built.The microstructural evolution in a directionally solidified succinonitile-2.5%(mass fraction) ethanol alloy was simulated.The results show that the primary dendrite spacing may vary in a range under a given solidification condition.Its value depends on the solidification history of the sample.The calculated upper and lower limits of primary dendrite spacing at different cooling rates are in good agreement with the experimental results.The effect factors of the solidification history dependence of the primary dendritic spacing were analyzed in detail.It indicates that the interfacial energy and the solute diffusion coefficients are the main factors if there is no convection in the liquid phase.