I come back with the question of austenite grain growth as I promised. We are making the simulation of austenite grain growth in 0.07%C 1.44%Mn 0.019%Cr 0.146%Mo 0.027%Si at 1100-1200 °C. Below you will see the necessary part of our driving file.

We put the mobility between 1/1 quite high, so that the grain growth fits our experimental data. (For reaction between 1/2 and 2/2, we put because we must give any other reaction between different phases. I understand that they don't affect the simulation because we have only austenite.)

This mobility is much higher than the data quoted in

Philippe Schaffnit, Charles Stallybrass, Joachim Konrad, Axel Kulgemeyer, Heike Meuser

**Dual-scale phase-field simulation of grain growth upon reheating of a microalloyed line pipe steel**,

International Journal of Materials Research 2010/04, Page 549-554

which is shown in the section 'MICRESS references'.

Figure 4 in this paper shows the product between mobility and interfacial energy in m^2/s. But the product of our mobility and interfacial energy in m^2/s will be in order of E-10 difference!!! This is weird! One argument can be that this publication simulatated the grain growth in 'microalloyed' steels. But I do not believe that only this will make such the difference.

My questions are:

1. Is there anything wrong in my simulation?

2. We noticed also that using this very high mobility makes the simulation much slower than using the low mobility. What's wrong?

3. Do you have any other reference for this kind of mobility in non-microalloyed steels? I am on my way of digging the information in the pile of literature.

Thanks and Happy Easter

nokkikku

# Flags and settings

# ==================

#

# Geometry

# --------

# Grid size?

# (for 2D calculations: AnzY=1, for 1D calculations: AnzX=1, AnzY=1)

# AnzX:

1000

# AnzY:

1

# AnzZ:

1000

# Cell dimension (grid spacing in micrometers):

# (optionally followed by rescaling factor for the output in the form of '3/4')

1

#

# Flags

# -----

# Type of coupling?

# Options: phase concentration temperature temp_cyl_coord

# [stress] [stress_coupled] [flow]

phase

# Type of potential?

# Options: double_obstacle multi_obstacle

double_obstacle

# Enable averaging of the driving force along the normal to the interface?

# Options: averaging no_averaging

no_averaging

#

# Phase field data structure

# --------------------------

# Coefficient for initial dimension of field iFace

# [minimum usage] [target usage]

0.10

# Coefficient for initial dimension of field nTupel

# [minimum usage] [target usage]

0.01

...

...

...

....

# Time input data

# ===============

# Finish input of output times (in seconds) with 'end_of_simulation'

# 'regularly-spaced' outputs can be set with 'linear_step'

# or 'logarithmic_step' and then specifying the increment

# and end value

# ('automatic_outputs' optionally followed by the number

# of outputs can be used in conjuction with 'linear_from_file')

linear_step 005.0 0020.0

linear_step 010.0 0250.0

linear_step 050.0 0600.0

end_of_simulation

# Time-step?

# Options: (real) automatic [0<factor_1<=1] [0<=factor_2] [max.] [min.]

# (Fix time steps: just input the value)

automatic

# Coefficient for phase-field criterion 1.00

# Number of iterations for initialisation?

5

#

#

# Phase data

# ==========

# Number of distinct solid phases?

2

#

# Data for phase 1:

# -----------------

# Simulation of recrystallisation in phase 1?

# Options: recrystall no_recrystall

no_recrystall

# Is phase 1 anisotrop?

# Options: isotropic anisotropic faceted antifaceted

isotropic

# Should grains of phase 1 be reduced to categories?

# Options: categorize no_categorize

no_categorize

#

# Data for phase 2:

# -----------------

# Simulation of recrystallisation in phase 2?

# Options: recrystall no_recrystall

no_recrystall

# Is phase 2 anisotrop?

# Options: isotropic anisotropic faceted antifaceted

isotropic

# Should grains of phase 2 be reduced to categories?

# Options: categorize no_categorize

no_categorize

#

# Grain input

# ===========

# Type of grain positioning?

# Options: deterministic random from_file

random

# Integer for randomization?

1000000

# Number of different types of grains?

1

# Number of grains of type 1?

230

# Input for grain type 1

# ----------------------

# Geometry of grain type 1

# Options: round rectangular elliptic

round

# Minimal value of x-coordinates? [micrometers]

0.00000

# Maximal value of x-coordinates? [micrometers]

1000.000

# Minimal value of z-coordinates? [micrometers]

0.00000

# Maximal value of z-coordinates? [micrometers]

1000.000

# Minimum grain radius? [micrometers]

100.000

# Maximum grain radius? [micrometers]

100.000

# Shall grain type 1 be stabilized or shall

# an analytical curvature description be applied?

# Options: stabilisation analytical_curvature

stabilisation

# Should the Voronoi criterion for grains of type 1 be applied?

# Options: voronoi no_voronoi

voronoi

# Phase number for grain type 1? (int)

1

# Minimal distance between grains (real) [micrometers]?

30.000

#

#

# Data for further nucleation

# ===========================

# Enable further nucleation?

# Options: nucleation no_nucleation [verbose|no_verbose]

no_nucleation

#

#

# Phase interaction data

# ======================

#

# Data for phase interaction 0 / 1:

# ---------------------------------

# Simulation of interaction between phase 0 and 1?

# Options: phase_interaction no_phase_interaction

# [standard|particle_pinning[_temperature]|solute_drag|redistribution_control]

no_phase_interaction

#

# Data for phase interaction 0 / 2:

# ---------------------------------

# Simulation of interaction between phase 0 and 2?

# Options: phase_interaction no_phase_interaction

# [standard|particle_pinning[_temperature]|solute_drag|redistribution_control]

no_phase_interaction

#

# Data for phase interaction 1 / 1:

# ---------------------------------

# Simulation of interaction between phase 1 and 1?

# Options: phase_interaction no_phase_interaction identical phases nb.

# [standard|particle_pinning[_temperature]|solute_drag|redistribution_control]

phase_interaction

# Type of surface energy definition between phases 1 and 1?

# Options: constant temp_dependent

constant

# Surface energy between phases 1 and 1? [J/cm**2]

7.00000E-05

# Type of mobility definition between phases 1 and 1?

# Options: constant temp_dependent dg_dependent

constant

# Kinetic coefficient mu between phases 1 and 1? [cm**4/(Js)]

0.22265E-02

#

# Data for phase interaction 2 / 2:

# ---------------------------------

# Simulation of interaction between phase 2 and 2?

# Options: phase_interaction no_phase_interaction identical phases nb.

# [standard|particle_pinning[_temperature]|solute_drag|redistribution_control]

phase_interaction

# Type of surface energy definition between phases 2 and 2?

# Options: constant temp_dependent

constant

# Surface energy between phases 2 and 2? [J/cm**2]

5.00000E-05

# Type of mobility definition between phases 2 and 2?

# Options: constant temp_dependent dg_dependent

constant

# Kinetic coefficient mu between phases 2 and 2? [cm**4/(Js)]

2.10125E-02

#

# Data for phase interaction 1 / 2:

# ---------------------------------

# Simulation of interaction between phase 1 and 2?

# Options: phase_interaction no_phase_interaction

# [standard|particle_pinning[_temperature]|solute_drag|redistribution_control]

phase_interaction

# Type of surface energy definition between phases 1 and 2?

# Options: constant temp_dependent

constant

# Surface energy between phases 1 and 2? [J/cm**2]

4.00000E-05

# Type of mobility definition between phases 1 and 2?

# Options: constant temp_dependent dg_dependent

constant

# Kinetic coefficient mu between phases 1 and 2? [cm**4/(Js)]

2.26841E-02

#

# Phase diagram - input data

# ==========================

# Equilibrium temperature (real) [K] between 1 and 2

1107.150

# Entropy of fusion between phase 1 and 2 ? (real) [J/(cm**3 K)]

1.000000

#

#

# Boundary conditions

# ===================

# Type of temperature trend?

# Options: linear linear_from_file profiles_from_file

linear

# Number of connecting points? (integer)

0

# Initial temperature at the bottom? (real) [K]

1373.150

# Temperature gradient in z-direction? [K/cm]

0.0000

# Cooling rate? [K/s]

0.0000

# Moving-frame system in z-direction?

# Options: moving_frame no_moving_frame

no_moving_frame

#

# Boundary conditions for phase field in each direction

# Options: i (insulation) s (symmetric) p (periodic/wrap-around) g (gradient) f (fixed)

# Sequence: E W (N S, if 3D) B T borders

pppp

# Unit-cell model symmetric with respect to the x/y diagonal plane?

# Options: unit_cell_symm no_unit_cell_symm

no_unit_cell_symm

#

#

# Other numerical parameters

# ==========================

# Phase minimum?

1.00E-05

# Interface thickness (in cells)?

5.00

#

#