Diffusion Simulations

In order to allow diffusion simulations to be performed with realistic conditions on alloys of practical importance, emphasis during the development of the Diffusion Module (DICTRA) has been on linking fundamental models to critically assessed thermodynamic and kinetic data.

As a result, the Diffusion Module (DICTRA) is very general and it is primarily the access to thermodynamic and kinetic data that determines if a problem can be simulated or not. This is, of course, under the assumption that the problem in question is diffusion controlled and that all other basic model assumptions are met.

It should also be emphasized that diffusion simulations are one-dimensional and that three different geometries, planar, cylindrical, and spherical, can be used. This is sufficient to model many cases of interest. A cylindrical geometry may, for example, be used both for modeling of diffusion through a tube wall, as well as the dissolution of a rod-shaped precipitate.

The Diffusion Module (DICTRA) requires a mobility database in addition to the standard thermodynamic and properties database that is used with Thermo-Calc. The mobility database contains information about the atomic mobility of individual components in relevant phases. Each mobility database is developed to correspond to a specific thermodynamic and properties database.