Setting Up the Moving Phase Boundary Simulation

The first region to be entered is entered in the same way as in the single-phase simulation.

@@ goto_module dictra_monitor

go d-m

@@ set_condition global T 0 1050; * N

set-cond glob T 0 1050; * N

A constant temperature equal to 1050 K is used in this simulation.

@@ enter_region ferrite

ent-reg ferrite

The phase interface between ferrite and austenite is created by introducing a region called austenite that is attached to the ferrite region. Regions are always separated by phase interfaces and must therefore always contain different matrix type phases.

ENTER_REGION

<NAME OF REGION>

<NAME OF EXISTING REGION TO ATTACH TO>

<ATTACH TO THE RIGHT OF EXISTING REGION Y/N>

enter_region

austenite

ferrite

y

The domain now consists of two regions: ferrite and austenite.

As in the single-phase simulation example, the regions must contain both grids and one active phase of type matrix. These are entered separately for both regions.

enter-grid

ferrite

1e-9

auto

enter-grid

austenite

1e-9

auto

For both the ferrite and austenite regions, the same grid is used as in the single-phase simulation example, i.e. the automatic (auto) grid point distribution. An appropriate grid is generated at the start of the simulation where the grid points are automatically distributed according to the entered composition profile and boundary conditions.

These grid types are used in diffusion simulations: automatic, linear, geometric, and double geometric. When you are setting up the simulation, in either Console Mode or Graphical Mode, a region must have a grid defined.

Example of the grid types linear, geometric and double geometric.

Now the initial composition of both phases is entered. In this case Fe is automatically chosen to be the dependent component.

enter-phase

active

ferrite

matrix

bcc

enter-phase

active

austenite

matrix

fcc

Both phases are assumed to be initially homogeneous, the bcc phase having 0.01 mass-% C and the fcc phase 0.15 mass-% C, as shown in the following:

enter-composition

ferrite

bcc

w-p

C

linear

0.01

0.01

enter-composition

austenite

fcc

w-p

C

linear

0.15

0.15

Set the simulation time and other parameters related to the time-step size.

set-simulation-time

1e5

y

1e4

1E-7

1E-7

Finally, save the simulation set-up to file.

save simple_moving_boundary yes