Binary alloys exhibit segregation of solute atoms at interfaces, which can have important effects on the physical and mechanical properties of the alloys. It is thus important to understand how the segregation depends on the interface type and thermodynamic variables of the system.
The segregation behavior will be investigated by simulating various types of alloys and interfaces. In particular, we will examine twist and tilt grain boundaries in single-phase fcc binary alloys. Two fundamental aspects will be investigated: (1) how the composition of boundary regions is affected by the bulk composition and temperature; (2) the spatial distribution of the two species in the boundaries. The simulations will be done using a combined molecular dynamics (MD) and monte carlo (MC) approach.
We will start with classical MC techniques employing Metropolis algorithm, and include the implementations such as chemical species exchanging. After the MC step, MD technique will be used to relax the atomic configurations. Potential between metal atoms will be described by Lennard-Jones, LJ, and Embedded Atom Method, EAM. Since in general LJ potential poorly describes the behavior of metals results obtained using LJ potential will be compared with EAM results.
By varying the temperature and composition of the system we hope to see different levels of segregation at the grain boundaries. We will simulate the various grain boundaries by implementing appropriate boundary conditions on the simulation box. Depending on the behavior found at these defects, we may examine segregation at a variety of inhomogeneities.