Monte Carlo simulation of solute aggregation in binary alloys: Domain boundary precipitation and domain growth

Abstract

Domain boundary precipitation and domain growth in binary polycrystalline materials are studied by applying the Monte Carlo simulation in two-dimensional squared lattice. The simulation is carried out on a hybrid lattice of the kinetic spin-exchange Ising model coupled with the Q-state Potts model. First of all, the static properties of this coupled model are studied, predicting just a small shiftdown of the critical point with enhanced Potts interactions. Subsequently, the dynamic properties, such as morphology and coarsening kinetics of the second phase precipitates as well as kinetics and scaling of the domain growth, are investigated in detail. Pronounced second phase precipitation at domain boundaries is observed at a temperature range just below critical point Tc as long as the solutes prefer to segregate onto the boundaries. However, the boundary precipitation is significantly prohibited at either high or low temperatures (T≫Tc or T≪Tc). We demonstrate that the domain growth is slowed down due to the pinning effect of the precipitates at the boundaries, no matter what the boundary migration ability is. The kinetics of boundary precipitation and domain growth in various systems are simulated. Both the Lifshitz-Slyozov-Wagner law for second phase coarsening and the linear law for the normal domain growth become broken due to the domain boundary precipitation. The scaling behavior of the domain growth is identified in present systems although a further confirmation may be required. ©1999 The American Physical Society.