An atomistic Monte Carlo simulation of precipitation in a binary system

Abstract

Abstract An atomistic Monte Carlo simulation of coherent precipitation on a body-centred cubic crystal lattice is presented. A binary system with atom types A and B is considered, while the ‘diffusion’ of the atoms is realized via a vacancy mechanism. Starting with a random distribution of 91 % A atoms and 9 % B atoms, the formation and growth of precipitates is simulated at a constant temperature of 773 K. As a result of the simulation, the precipitate radii distributions at different states of the system and the time evolution of the precipitate mean radii have been calculated. The results of the simulation are compared with the predictions of the classical Lifshitz–Slyozov–Wagner (LSW) theory. At the beginning of precipitation the mean radius R¯(t) grows proportional to t0.180, while at later states the growth exponent approaches the classical value of 1/3. In order to reveal the growth exponent's exact value, an even larger simulation is required, which remains as an interesting task for the future.