Models for the
determination of kinetic phase diagrams and kinetic phase separation
domains
J.H. Los, , , M. van den Heuvel, W.J.P. van Enckevort, E. Vlieg, H.A.J.
Oonk, M. Matovic and J.C. van Miltenburg
Computer Coupling of Phase Diagrams and Thermochemistry 30 (2006)
216-224
Abstract
Several theoretical models for the determination of kinetic phase
diagrams for solid solution growth from the liquid phase are presented
and compared to each other. These models include a Monte Carlo
simulation model, used as a reference model, a previously defined
analytical model, based on linear non-equilibrium thermodynamics, and a
new model, rooted in the kinetics at kink sites.
All models have in common that the composition of the growing solid
phase tends to the liquid phase composition for increasing
undercooling, enhancing mixing even for systems with a strong tendency
to phase separation. However, depending on the system parameters
considerable quantitative differences can occur between the results
from the model based on non-equilibrium thermodynamics and the MC
model. Instead, the new model follows very well the trends of the MC
simulations, both for well-mixing systems and for phase separating
systems.
For phase separating systems the analytical models predict kinetic
phase separation domains, zones in the kinetic phase diagram yielding
steady state growth of more than one solid phase with different
compositions. According to MC simulations such domains in phase space
correspond to domain formation in real space. Also in this case the new
model is consistent with the MC results.