The Diffusion Module (DICTRA) is an Add-on Module to Thermo-Calc that makes modeling multicomponent diffusion-controlled transformations simple and accessible. The Diffusion Module (DICTRA) is based on the numerical solution of the multicomponent diffusion equations and the CALPHAD approach.
Questions Diffusion Simulations Can Help You Answer
The Diffusion Module (DICTRA) is a general tool for making diffusion simulations, but some typical questions it can help you answer are:
How long of a holding time is required at a specific temperature to homogenize the as-cast microstructure?
How long of an annealing time is needed to dissolve precipitates of a given size?
How does the cooling or heating rate influence the amount of phases transformed?
What elemental profiles result post welding or other similar joining operations?
Will undesirable phases form when joining two dissimilar materials?
The Diffusion Module (DICTRA) Allows You to Simulate:
Microsegregation during solidification
Homogenization of alloys
Growth/dissolution of secondary phases, such as carbides, nitrides, or intermetallic phases
Coarsening of precipitate phases
Allotropic phase transformations, such as austenite to ferrite transformations in steel, or hcp (alpha-Ti) to bcc (beta-Ti) in titanium alloys
Carburization, nitriding, and carbonitriding of high-temperature alloys and steels
Interdiffusion in compounds, such as coating systems, dissimilar joints, and so on
Post weld heat treatment (interdiffusion and related phase changes)
Sintering of cemented-carbides
Generic Models for Flexible Use
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.
Databases for Diffusion Simulations
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.
The Diffusion Module (DICTRA) is available as an Add-on to a Thermo-Calc license. In order to run the Diffusion Module (DICTRA), it is necessary to have a license for Thermo-Calc, at least one thermodynamic and properties database, and at least one mobility database. If you are interested in purchasing a license for this Module, please contact us to discuss which license is right for you.