Dynamical lattice models for binary alloys under irradiation: Mean-field solutions and Monte Carlo simulations

Ordering in binary bcc alloys under irradiation is studied using dynamical nearest-neighbor lattice models. Steady-state mean-field solutions (point and pair approximation) and Monte Carlo simulations are presented. Both for a model with a direct-exchange transport mechanism and for a model with a vacancy transport mechanism, it is found that the A2-B2 ordering transition becomes first order beyond a tricritical point (i.e., at high radiation flux). The effect of replacement collision sequences, induced by high-energy radiation, is also investigated.