Grain-boundary ordering, segregation, and melting transitions in a two-dimensional lattice-gas model

A two-dimensional lattice-gas model of a binary-ordering-alloy system was used to study the phase transitions and the atomic configuration near a Σ=5 grain boundary. The cluster variation method was used to study order-disorder and melting transitions in the bulk alloys. The complete binary phase diagrams were constructed for two different sets of interaction-energy assumptions. Simulations based on the same model were performed to study these transitions in the grain-boundary region. In addition, the model also yields information on the segregation behavior of the alloying elements in the grain-boundary region.