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

Domain boundary precipitation and domain growth in binary polycrystalline m aterials are studied by applying the Monte Carlo simulation in two-dimensio nal squared lattice. The simulation is carried out on a hybrid lattice of t he kinetic spin-exchange Ising model coupled with the e-state Potts model. First of all, the static properties of this coupled model are studied, pred icting just a small shiftdown of the critical point with enhanced Potts int eractions. Subsequently, the dynamic properties, such as morphology and coa rsening kinetics of the second phase precipitates as well as kinetics and s caling 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 T-c as long as the solutes prefer to segregate o nto the boundaries. However, the boundary precipitation is significantly pr ohibited at either high or low temperatures (T much greater than T-c or T m uch less than T-c). We demonstrate that the domain growth is slowed down du e to the pinning effect of the precipitates at the boundaries, no matter wh at the boundary migration ability is. The kinetics of boundary precipitatio n and domain growth in various systems are simulated. Both the Lifshitz-Sly ozov-Wagner law for second phase coarsening and the linear law for the norm al domain growth become broken due to the domain boundary precipitation. Th e scaling behavior of the domain growth is identified in present systems al though a further confirmation may be required. [S0163-1829(99)00434-8].