The alteration of phase stability due to the continuous production of forced atomic displacements, as is the case under irradiation, is studied. A simple kinetic model of a binary alloy exhibiting phase separation is investigated, and two limiting cases are considered: nearest-neighbor ballistic exchanges and arbitrary-length ballistic exchanges. The model is simultaneously studied by direct kinetic Monte Carlo simulations, and by theoretical approaches based in the description of the steady state by effective thermodynamics. Two theoretical frameworks are considered: a microscopic description based in effective interactions, and a macroscopic description based in effective free energies constructed over a modified Cahn-Hilliard equation. Developments of these models are proposed to allow for quantitative predictions. For nearest-neighbor ballistic exchanges, the steady-state phase diagram is evaluated for each of the approaches and the results are directly compared. In the case of arbitrary-length ballistic exchanges, the appearance of labyrinthine mesoscopic structures at steady state is rationalized in terms of the competition between short-range attractive and long-range repulsive effective interactions. The favorable comparison between the theoretical results and the direct Kinetic Monte Carlo simulations shows that the long-term behavior of this inherently far-from-eauilibrium system can be described in terms of effective thermodynamic potentials.
|Original language||English (US)|
|Number of pages||11|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jan 1 1999|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics