Tracer diffusion in an alloy in which the trajectories of one of the species was biased was examined as a model of mass transport with attendant segregation to extended defects (e.g., dynamic strain ageing, grain-boundary segregation). More specifically, Monte Carlo simulation was used to describe the non-equilibrium diffusive behavior of the components of a two-dimensional lattice gas comprising A and B atoms where one of the species (B) interacted with randomly distributed line defects to create equilibrium atmospheres at long times. Various kinetic assumptions and defect densities were explored to highlight the role of B-atom mobility and defect interaction strength on the transport behavior of the A atoms. From the calculated instantaneous diffusivity, several diffusive regimes were then identified and related to evolving segregation profiles and, in particular, to the free area available for diffusion.

Tracer Diffusion in the Presence of Segregating Obstacles. J.M.Rickman: Physica A, 2011, 390[3], 456-62