Kinetics of antiphase domain boundaries during an L1₂ order-disorder phase transformation: A Monte Carlo simulation

Abstract

The formation of the L1₂ phase in an A₃B intermetallic solid solution has been investigated by Monte Carlo simulation. The ordering is modelled with a simple atomic exchange mechanism based on a fcc Ising model with appropriate values for the pairwise atomic interactions. It is shown that the ordering kinetics occurs on two time scales: nucleation and growth of ordered domains and the annealing of antiphase boundaries between the domains. The model is applied to the L1₂ ordered Ni₃Al phase under various irradiation conditions. It is demonstrated that the migration and annihilation of antiphase boundaries largely determine the time evolution of the L1₂ phase.