Without Thermodynamic and Mobility Database for Solidification Simulation

[parimalmaity]

Hello Bernd,
I would like to simulate the Solidification for Ni-based alloy system. Suppose, if I don't have Thermodynamic and Mobility Databases. Can I simulate the solidification in MICRESS? If yes, Please let me know the procedure. I read previous topic in this forum but unfortunately no one has similar problem for supper alloy based system hence I raised a new request.
Regards
Parimal

[Bernd]

Hi Parimal,

in principle, the answer is "yes". However, you cannot reasonably describe the multicomponent superalloys with multicomponent linearized phase diagrams, i.e. it would be wise rather to refer to a pseudo-binary diagram. This automatically restricts you to considering only liquid and fcc as phases.
I did this once for 3D-Dendrites of IN718 for sake of simulation speed. Until a fraction of liquid of ~50% the result was practically identical to a multicomponent simulation. Of course, you should not expect to be able to describe processes towards the end of solidification where other phases come into play...

Bernd

[parimalmaity]

Hello Bernard,
Thank you for your reply.
Lets say, I am ok with pseudo-binary phase with liquid and FCC as phase. How to use this for multi-components system? Could you please let me know the procedure?
As you said you have done this before, could you please share your driving file with me. If I have further questions on the driving file I will post that accordingly.
Regards
Parimal

[Bernd]

Dear Parimal,

For calculation of a pseudo-binary phase diagram I derived the relations

Formel_Pseudobinary.JPG (34.76 KiB) Viewed 3071 times

If need a reference for that, I published the formulae in:

B. Böttger, C. Haberstroh, N. Giesselmann, "Cross-Permeability of the Semisolid Region in Directional Solidification: A Combined Phase-Field and Lattice-Boltzmann Simulation Approach", JOMM 68 1 (2016) 27-36 DOI: http://dx.doi.org/10.1007/s11837-015-1690-3

In those times, I made the comparison to a multicomponent simulation coupled to the TTNI6 database, and it turned out that the results (fraction solid vs. temperature for 3D-dendrite growth) was pretty the same for small values of fraction solid:

fS_T.png (68.76 KiB) Viewed 3071 times

Starting from the linearization output in the .log file I calculated the pseudo-binary parameters for the "linearTQ" where the derivatives dc/dt are treated analogously to the concentrations themselves.

The formula works only for atomic percent, therefore I made the MICRESS input in at% like:

....
# Concentration data
# ==================
# Number of dissolved constituents? (int)
1
# Type of concentration?
# Options: atom_percent (at%)
# weight_percent (wt%)
atom_percent
#
# Finish input of diffusion data with 'end_diffusion_data'.
#
# Options: diff no_diff infinite infinite_restricted
# multi database_global database_local from_file
# [+b] for grain-boundary diffusion
# ('multi' can be followed by a string of "n", "d", "g", "l", or "f"
# to describe each contribution: respectively no diffusion,
# user-defined diffusion coefficient,'global' or 'local' value from
# database, and 'from file, the default is global values from database).
# Extra line option (prefactor on time step): cushion <0-1>
# Extra line option: infinite_limit [cm**2/s]
# How shall diffusion of component 1 in phase 0 be solved?
1 0 diff
# Diff.-coefficient:
# Prefactor? (real) [cm**2/s]
1.00000E-05
# Activation energy? (real) [J/mol]
0.0000
# How shall diffusion of component 1 in phase 1 be solved?
1 1 diff
# Diff.-coefficient:
# Prefactor? (real) [cm**2/s]
1.00000E-08
# Activation energy? (real) [J/mol]
0.0000
end_diffusion_data
#
#
# Phase diagram - input data
# ==========================
#
# List of phases and components which are stoichiometric:
# phase and component(s) numbers
# List of concentration limits:
# <Limits>, phase number and component number
# End with 'no_more_stoichio' or 'no_stoichio'
no_more_stoichio
#
#
#
#
# Is a thermodynamic database to be used?
# Options: database database_verbose no_database
no_database
#
# Input of the phase diagram of phase 0 and phase 1:
# --------------------------------------------------
# Which phase diagram is to be used?
# Options: linear linearTQ
linearTQ
# Please input linearisation data in the TQ format!
# T0 [K] ?
1617.8000
# dG [J/cm**3] ?
-10.818460
# dSf+ [J/cm**3K] ?
1.0442562
# dSf- [J/cm**3K] ?
0.99451601
# dH [J/cm**3] (dummy)?
1343.7991
# c0 von Komponente 1 in phase 0 ? [at%]
51.4075
# c0 von Komponente 1 in phase 1 ? [at%]
46.7872
# m of component 1 in phase 0 ? [at%]
-14.2460
# m of component 1 in phase 1 ? [at%]
-55.2064
# dcdT of component 1 in phase 0 ? [at%]
-2.63E-3
# dcdT of component 1 in phase 1 ? [at%]
3.24E-3
# Please specify the redistribution behaviour of each component:
# Format: forward [backward]
# Options: nple para paraTQ normal ATC [mob_corr|verbose]
# Component 1
normal
#
#
# Initial concentrations
# ======================
# How shall initial concentrations be set?
# Options: input equilibrium from_file [phase number]
equilibrium
# Initial concentration of component 1 in phase 0 ? [at%]
51.407
#
...

Bernd