Ferrite / Pearlite Formation
Ferrite / Pearlite Formation
Dear Bernd,
i want to model the formation of an ferrite / pearlite structure with cementite as an unresolved phase - like in the examples.
my approach was to use an ferrite / pearlite structure as initial, but to declare the pearlite grains as austenite.
by cooling down this intial strucutre i want to achieve a matrix of ferrite and unresolved cementite.
the only thing i did, was to edit the GammaAlphaPearlite by changing the initial structure and matching the initial concentrations But there are some problems during running the simulation. it is extremly slow. i started the simulation on friday and today (on monday) i cancelled. furthermore, the results were very confusing, for example : the grain boundarys are vanishing. BUT by considering other output files (like fraction of phase 3 (Cementite)) the structure is visible and it seems to work.
recently i started the simulation again. for that reason i cannot upload the results - maybe tomorrow. but maybe you can already help me by the problem of simulation duration?
kind regards
raphael
i want to model the formation of an ferrite / pearlite structure with cementite as an unresolved phase - like in the examples.
my approach was to use an ferrite / pearlite structure as initial, but to declare the pearlite grains as austenite.
by cooling down this intial strucutre i want to achieve a matrix of ferrite and unresolved cementite.
the only thing i did, was to edit the GammaAlphaPearlite by changing the initial structure and matching the initial concentrations But there are some problems during running the simulation. it is extremly slow. i started the simulation on friday and today (on monday) i cancelled. furthermore, the results were very confusing, for example : the grain boundarys are vanishing. BUT by considering other output files (like fraction of phase 3 (Cementite)) the structure is visible and it seems to work.
recently i started the simulation again. for that reason i cannot upload the results - maybe tomorrow. but maybe you can already help me by the problem of simulation duration?
kind regards
raphael
Re: Ferrite / Pearlite Formation
Hi Rafael,
I don't see anything which is obviously wrong, apart from some "," instead of "." in the initial concentration input which could lead to a wrong interpretation.
However, you changed strongly the initial composition and initial microstructure, so that numerical parameters may be completely wrong in this context. I would need all the input files (.dri, .ges5, initial microstructure) in order to find out more!
Bernd
I don't see anything which is obviously wrong, apart from some "," instead of "." in the initial concentration input which could lead to a wrong interpretation.
However, you changed strongly the initial composition and initial microstructure, so that numerical parameters may be completely wrong in this context. I would need all the input files (.dri, .ges5, initial microstructure) in order to find out more!
Bernd
Re: Ferrite / Pearlite Formation
Hi Bernd,
as attached you can find the ges file, dri.-file and images of the phase-output and fraction of cementite (frac3) output.
The Initial microstructure is too lagre, so i am not able to upload it. Is there another way to upload such large files ?
as attached you can find the ges file, dri.-file and images of the phase-output and fraction of cementite (frac3) output.
The Initial microstructure is too lagre, so i am not able to upload it. Is there another way to upload such large files ?
- Attachments
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- Initial_frac3_mcr.png (363.68 KiB) Viewed 5854 times
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- Initial_phas_mcr_2.png (46.42 KiB) Viewed 5854 times
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- Initial_phas_mcr_1.png (39.13 KiB) Viewed 5854 times
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- GammaAlphaPearlite_initial_dri.txt
- (29.03 KiB) Downloaded 380 times
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- FeCMn1.GES5
- (44.56 KiB) Downloaded 370 times
Re: Ferrite / Pearlite Formation
Dear Rafael,
At a first glimpse your results do not look so bad...
If the initial microstructure is too big for uploading, you could send it to me by email. Much better, however, would be to reduce the domain size of your simulation which also makes testing much faster. Then, you could easily upload the initial microstructure to the forum. It is always better to have small simulations for testing and calibrating, and make the big simulation once this has been achieved!
Bernd
At a first glimpse your results do not look so bad...
If the initial microstructure is too big for uploading, you could send it to me by email. Much better, however, would be to reduce the domain size of your simulation which also makes testing much faster. Then, you could easily upload the initial microstructure to the forum. It is always better to have small simulations for testing and calibrating, and make the big simulation once this has been achieved!
Bernd
Re: Ferrite / Pearlite Formation
Dear Bernd,
I made the initial structure much smaller (Matrix size). I ran the simulation. An improvement is that we do not have the austenite phase any more at the end of the transformation time. However, the result is still not satisfying. The main problem i think is thick interfaces. also the small pearlite phases doses not tranform. I wanted to ask if you have any idea how we cam improve the model?
Best regards,
Mehnoush
I made the initial structure much smaller (Matrix size). I ran the simulation. An improvement is that we do not have the austenite phase any more at the end of the transformation time. However, the result is still not satisfying. The main problem i think is thick interfaces. also the small pearlite phases doses not tranform. I wanted to ask if you have any idea how we cam improve the model?
Best regards,
Mehnoush
- Attachments
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- Initial_mhm_phas_mcr.png (18.31 KiB) Viewed 5747 times
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- Initial_mhm_conc1_mcr.png (44.02 KiB) Viewed 5747 times
Re: Ferrite / Pearlite Formation
Dear Mehnoush,
is the input file different from what Rafael showed before? Could you please attach it?
Bernd
is the input file different from what Rafael showed before? Could you please attach it?
Bernd
Re: Ferrite / Pearlite Formation
a little bit.i have attached it.
- Attachments
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- GammaAlphaPearlite_initial_dri _mhm_v2.txt
- (30.27 KiB) Downloaded 349 times
Re: Ferrite / Pearlite Formation
Dear Mehnoush,
I have seen that you changed the nucleation conditions. Now, you additionally nucleate phase 3 (cementite) without using the "unresolved" model - what are the reasons for that?
The reason for using the "unresolved" model for cementite was that it is not possible to resolve this phase correctly at the given resolution. Therefore it is allowed spreading as diffuse eutectoid mixture (see .frac3 distribution which Rafael showed above). At least for the cementite which nucleates at triple points you do not allow that anymore. Maybe, this is the problem.
Bernd
I have seen that you changed the nucleation conditions. Now, you additionally nucleate phase 3 (cementite) without using the "unresolved" model - what are the reasons for that?
The reason for using the "unresolved" model for cementite was that it is not possible to resolve this phase correctly at the given resolution. Therefore it is allowed spreading as diffuse eutectoid mixture (see .frac3 distribution which Rafael showed above). At least for the cementite which nucleates at triple points you do not allow that anymore. Maybe, this is the problem.
Bernd
Re: Ferrite / Pearlite Formation
HI Bernd,
we finaly could obtain the Ferrite/pearlite structure by cooling down austenite/ferrite structure.
kow we want to simulation the heating of the obtained structure with 100000 K/s but the results are not looking good. the austenite phase is formed as big massive grain also grain interfaces are fuzzy and thick. do you have any hint that can help us i attached the results.
Many thanks,
Mehnoush
we finaly could obtain the Ferrite/pearlite structure by cooling down austenite/ferrite structure.
kow we want to simulation the heating of the obtained structure with 100000 K/s but the results are not looking good. the austenite phase is formed as big massive grain also grain interfaces are fuzzy and thick. do you have any hint that can help us i attached the results.
Many thanks,
Mehnoush
- Attachments
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- results at the 1340 K
- dt100000_real_phas_mcr.png (25.92 KiB) Viewed 5725 times
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- results at the 1039 K
- dt100000_real_phas_mcr.png (25.8 KiB) Viewed 5725 times
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- the initial structure obtained from austenite/ferrite initial structure
- initial_structure.png (14.95 KiB) Viewed 5725 times
Re: Ferrite / Pearlite Formation
Hi Mehnoush,
I cannot see anything from the results. Did you change the length scale? May I see the driving file?
Bernd
I cannot see anything from the results. Did you change the length scale? May I see the driving file?
Bernd