Solidification in the one-dimensional model for a disordered binary alloy under diffusion

Abstract:

The propagation of the solidification front of a binary alloy growing from its melt is studied by Monte-Carlo simulation and by analytical approximation methods. The simulation shows that in the one-phase region the alloy grows steadily with a velocity controlled solely by kinetics. In the two-phase region, the previously reported anomaly for the diffusionless growth is removed by the diffusion of atoms and the diffusional t ^1/2 growth law is confirmed at least in the range where the diffusionless process is slower than diffusion. We cannot rule out, however, that the anomaly occurring in the diffusionless case persists even under diffusion, when the diffusionless growth asymptotically is faster than a typical diffusion process. The Monte-Carlo simulations are compared with an approximate analytical description ignoring correlations between the components.