precipitation of Ternary Alloy

solid-solid phase transformations, influence of stresses and strains
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1994513kong
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precipitation of Ternary Alloy

Post by 1994513kong » Tue Jun 05, 2018 1:02 pm

when the precipitation growing up,Only the border is thickening。I don't know which parameters to change this situation.

deepumaj1
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Re: precipitation of Ternary Alloy

Post by deepumaj1 » Tue Jun 05, 2018 2:02 pm

Hi. Can you give a little more details about your simulation set up? Also, if possible, can you give a snapshot of the thickening borders? Do you see any spreading of the interface??

Deepu

1994513kong
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Re: precipitation of Ternary Alloy

Post by 1994513kong » Wed Jun 06, 2018 7:44 am

Dear Depeu
If possible, can you give me some suggestion?

1994513kong
Last edited by 1994513kong on Wed Jun 06, 2018 8:02 am, edited 1 time in total.

1994513kong
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Re: precipitation of Ternary Alloy

Post by 1994513kong » Wed Jun 06, 2018 8:01 am

deepumaj1 wrote:Hi. Can you give a little more details about your simulation set up? Also, if possible, can you give a snapshot of the thickening borders? Do you see any spreading of the interface??

Deepu
Dear Depeu
I want to get the growing-up like image1 rather than image2.and the setting is listed as follow
# 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')
# 'first' : additional output for first time-step
# 'end_at_temperature' : additional output and end of simulation
# at given temperature
0.001
linear_step 0.01 2
end_of_simulation
# Time-step?
# Options: fix ...[s] automatic automatic_limited
automatic
# Coefficient for phase-field criterion 1.00
# Coefficient for segregation criterion 0.900
# Number of steps to adjust profiles of initially sharp interfaces [exclude_inactive]?
20
#
# Phase data
# ==========
# Number of distinct solid phases?
1
#
# Data for phase 1:
# -----------------
# Simulation of recrystallisation in phase 1?
# Options: recrystall no_recrystall [verbose|no_verbose]
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
categorize
#
# Orientation
# -----------
#
# Grain input
# ===========
# Type of grain positioning?
# Options: deterministic random [deterministic_infile] from_file
deterministic
# NB: the origin of coordinate system is the bottom left-hand corner,
# all points within the simulation domain having positive coordinates.
# Number of grains at the beginning?
4
# Input for grain type 1
# ----------------------
# Geometry of grain type 1
# Options: round rectangular elliptic round_inverse
round
# Center x,z coordinates [micrometers], grain number 1?
10
10
# Grain radius? [micrometers]
0.3
# 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
no_voronoi
# Phase number? (int)
1
# Input data for grain number 2:
# Geometry?
# Options: round rectangular elliptic round_inverse
round
# Center x,z coordinates [micrometers], grain number 2?
30
10
# Grain radius? [micrometers]
0.3
# 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
no_voronoi
# Phase number? (int)
1
# Input for grain type 3
# ----------------------
# Geometry of grain type 3
# Options: round rectangular elliptic round_inverse
round
# Center x,z coordinates [micrometers], grain number 3?
10
30
# Grain radius? [micrometers]
0.3
# Shall grain type 3 be stabilized or shall
# an analytical curvature description be applied?
# Options: stabilisation analytical_curvature
stabilisation
# Should the Voronoi criterion for grains of type 3 be applied?
# Options: voronoi no_voronoi
no_voronoi
# Phase number? (int)
1
# Input for grain type 4
# ----------------------
# Geometry of grain type 4
# Options: round rectangular elliptic round_inverse
round
# Center x,z coordinates [micrometers], grain number 4?
30
30
# Grain radius? [micrometers]
0.3
# Shall grain type 4 be stabilized or shall
# an analytical curvature description be applied?
# Options: stabilisation analytical_curvature
stabilisation
# Should the Voronoi criterion for grains of type 4 be applied?
# Options: voronoi no_voronoi
voronoi
# Phase number? (int)
1
#
#
#
# Data for further nucleation
# ===========================
# Enable further nucleation?
# Options: nucleation nucleation_symm 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]
phase_interaction
# 'DeltaG' options: default
# avg ... [] max ... [J/cm**3] smooth ... [degrees] noise ... [J/cm**3]
avg 1 max 20 smooth 15
# I.e.: avg +1.00 smooth +15.0 max +2.00000E+01
# Type of interfacial energy definition between phases 0 and 1?
# Options: constant temp_dependent
constant
# Interfacial energy between phases phases 0 and 1? [J/cm**2]
# [max. value for num. interface stabilisation [J/cm**2]]
5E-6
# Type of mobility definition between phases phases 0 and 1?
# Options: constant temp_dependent dg_dependent [fixed_minimum]
constant
# Kinetic coefficient mu between phases phases 0 and 1 [ min. value ] [cm**4/(Js)] ?
4e-6
# 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 interfacial energy definition between phases 1 and 1?
# Options: constant temp_dependent
constant
# Interfacial energy between phases phases 1 and 1? [J/cm**2]
# [max. value for num. interface stabilisation [J/cm**2]]
5E-4
# Type of mobility definition between phases phases 1 and 1?
# Options: constant temp_dependent dg_dependent [fixed_minimum]
constant
# Kinetic coefficient mu between phases phases 1 and 1 [ min. value ] [cm**4/(Js)] ?
2.96e-10
#
#
#
# Concentration data
# ==================
# Number of dissolved constituents? (int)
1
# Type of concentration?
# Options: atom_percent (at%)
# weight_percent (wt%)
atom_percent
#
#
# Diffusion Data
# --------------
# ["Terse Mode": Each line starts with component number and phase number]
# Options: diagonal [x] multi [y(1..k)]
# x: one of the characters "n", "d", "g", "l", "z", "i", "I", or "f"
# y: chain of "n", "d", "g", "l", "z", or "f" (for each component)
# default: "g" resp. "gggg..."
# Rem: "n":no diffusion, "d": input, "f": T-dep. from file
# "i":infinite, "I": infinite in each grain
# from database: "g": global, "l": local, "z" global z-segmented
# Extra option [+b] for grain-boundary diffusion
# Extra line option (prefactor on time step): cushion <0-1>
# Extra line option: infinite_limit [cm**2/s]
# Extra line option: maxfactor_local [real > 1.0] (default: 10.0)
# Extra line option: factor [real > 0.]
# Finish input of diffusion data with 'end_diffusion_data'.
#
# How shall diffusion of component 1 in phase 0 be solved?
diff
# Diff.-coefficient:
# Prefactor? (real) [cm**2/s]
5.00000E-06
# Activation energy? (real) [J/mol]
0.0000
# How shall diffusion of component 1 in phase 1 be solved?
diff
# Diff.-coefficient:
# Prefactor? (real) [cm**2/s]
1.00000E-12
# Activation energy? (real) [J/mol]
0.0000
#
#
#
# Phase diagram - input data
# ==========================
#
# List of phases and components which are stoichiometric:
# phase and component(s) numbers
# List of concentration limits (at%):
# <Limits>, phase number and component number
# List for ternary extrapolation (2 elements + main comp.):
# <interaction>, component 1, component 2
# Switches: <stoich_enhanced_{on|off}> <solubility_{on|off}>
# End with 'no_more_stoichio' or 'no_stoichio'
no_stoichio

ImageImage

deepumaj1
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Re: precipitation of Ternary Alloy

Post by deepumaj1 » Wed Jun 06, 2018 8:58 am

Hi 1994513kong,
Thanks for sharing the data. I'm still a little confused here on the images you have shared. Are these coming from the same simulation? Following are my suggestions:

1. As far as I understand, you want to have the precipitates in the square shape as show in image 1. Right? But there is a problem here with image 1. The interface in image1 (blue region) has spread out so much. This could be due to several reasons that includes bad numerical parameters, bad thermodynamics and so on. I would like to recommend you to have a look at your driving force output and also recheck your thermodynamics for rectifying this one.

This situation is also possible in systems like multi-component steel where you have a very fast diffusing specie along with slow diffusing ones. But I can tell about that only if i can have an idea of your system. You may also note that you don't have the phase 1 at all in image1.

2. You have defined your phase 1 as isotropic, which means you have equal growth rate in all directions. Hence, you will end up in rounded shaped precipitates like the one in image2. I would ideally expect you to have some anisotropy here (probably the Faceted anisotropy) so that you can make the precipitates grow in the shape you want

3. The intertfacial mobility value (Kinetic coefficient mu) in you input file doen't look very good (looks very low). You can get a good starting value from micress examples of solidification and tune it up based on the response. For this, I would recommened you to look at other outputs, especially the driving force output.


Do revert if you have further questions.

Best,
Deepu

1994513kong
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Re: precipitation of Ternary Alloy

Post by 1994513kong » Wed Jun 06, 2018 10:47 am

deepumaj1 wrote:Hi 1994513kong,
Thanks for sharing the data. I'm still a little confused here on the images you have shared. Are these coming from the same simulation? Following are my suggestions:

1. As far as I understand, you want to have the precipitates in the square shape as show in image 1. Right? But there is a problem here with image 1. The interface in image1 (blue region) has spread out so much. This could be due to several reasons that includes bad numerical parameters, bad thermodynamics and so on. I would like to recommend you to have a look at your driving force output and also recheck your thermodynamics for rectifying this one.

This situation is also possible in systems like multi-component steel where you have a very fast diffusing specie along with slow diffusing ones. But I can tell about that only if i can have an idea of your system. You may also note that you don't have the phase 1 at all in image1.

2. You have defined your phase 1 as isotropic, which means you have equal growth rate in all directions. Hence, you will end up in rounded shaped precipitates like the one in image2. I would ideally expect you to have some anisotropy here (probably the Faceted anisotropy) so that you can make the precipitates grow in the shape you want

3. The intertfacial mobility value (Kinetic coefficient mu) in you input file doen't look very good (looks very low). You can get a good starting value from micress examples of solidification and tune it up based on the response. For this, I would recommened you to look at other outputs, especially the driving force output.


Do revert if you have further questions.

Best,
Deepu
Dear Deepu
The image1 and 2 come from ternary system and binary system 。I just want to try precipitation of ternary system。But something going wrong make me feel unhappy。 The intertfacial mobility value (Kinetic coefficient mu) may influent the simulation time which I don't want to be too long。Or I have some misunderstanding about it。 About anisotropy,I think isotropy may be simpler to analysis the growing up 。Under stress,round shap will change in square, which I want to observe。
Thank you very much for your advice.If you have any new ideas, I'm glad to learn how to make my dri file run well。

sincerely
1994513kong

deepumaj1
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Re: precipitation of Ternary Alloy

Post by deepumaj1 » Wed Jun 06, 2018 12:08 pm

Dear 1994513kong,
Are you dealing with steels? If yes, are you using any redistribution models like nple or para?

Interfacial mobility do influence simulation time, but it do influence your result for the typical grid sizes we use. Hence, I would recommend you not to use interfacial mobility to speed up the simulation. Tune the interfacial mobility so that you get a quantitatively sound result. For increasing the speed of your simulation, try decreasing your domain size. Just have a domain with only one precipitate in it. Tune up all you parameters and then scale it up to a big simulation domain. Phase field simulation do take time. You can make your simulation run in parallel to speed it up. But for parameter tuning, use a very small domain as mentioned.

As far as stress is concerned, please note that Micress deal only with elastic strains. But in my opinion, you can get a stable ternary isotropic simulation and then worry about the stresses.

Best,
Deepu

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