Cooling rate

dendritic solidification, eutectics, peritectics,....
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shaojielv
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Cooling rate

Post by shaojielv » Tue Apr 13, 2021 6:50 am

Everybody is good:
In the learning process of MICRESS software, I noticed that there were two types of dendrite interface growth rate and cooling rate. I was a little confused as to whether these two cooling rates were the same thing.If not, how exactly should we understand it?And what I'm talking about here is that the growth rate at the interface is reflected in the equation of the multiphase field, but the cooling rate is not expressed in the equation, or can the cooling rate be reflected in the equation of the multiphase field?If there is a friend who knows, can you help me answer this question?I would greatly appreciate your help.
Wish you a happy life!
Yours:Lv shaojie

Bernd
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Re: Cooling rate

Post by Bernd » Tue Apr 13, 2021 11:03 am

Dear Lv shaojie,

Growth rate and cooling rate are two completely different quantities, which are linked by the temperature dependency of the driving force for phase transformation. Admittedly, in solidification processes this link is quite strong:

d(ΔG)/dT = ΔS ~ 1 J/(Kcm3)

As I explained for your other question, temperature is treated as boundary condition to our phase-field equation, and thus the cooling rate does not appear explicitly there.

Bernd

shaojielv
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Re: Cooling rate

Post by shaojielv » Tue Apr 13, 2021 2:21 pm

Dear Bernd,
I am very happy to receive your reply so soon.I've understood the difference between the two cooling rates you mentioned.I also have a question: the cooling rate mentioned in MICRESS is understood by me to be the cooling rate of metal liquid rather than the solidification rate, I wonder if this is correct?Because I want to study the influence of the cooling rate in the casting process on the dendrite growth, if my understanding is OK, then what is simulated by MICRESS is the cooling rate of metal liquid rather than the solidification rate?If so, how should I study the solidification rate through MICRES?
Thank you very much for answering my questions in your busy schedule. Wish you a happy life and smooth work!
Lv Shaojie

Bernd
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Joined: Mon Jun 23, 2008 9:29 pm

Re: Cooling rate

Post by Bernd » Tue Apr 13, 2021 3:01 pm

Dear Lv shaojie,

The cooling rate which you apply in MICRESS refers to the temperature at the bottom of the simulation domain, irrespective of the phase or material which is there. If you furthermore define a temperature gradient (in z-direction of the domain), then the temperature in other regions of the domain may be different.

The way how to determine the solidification rate (front velocity, rate of fraction solid, etc.) by MICRESS simulations depends on the type of process which you want to study. The central question is on the temperature gradient, i.e. whether you consider directional solidification or equiaxed casting. Depending on the exact thermal boundary conditions of the process, latent heat needs to be included or not.

Which type of solidification or casting process do you want to study?

Best wishes
Bernd

shaojielv
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Re: Cooling rate

Post by shaojielv » Tue Apr 13, 2021 3:23 pm

Dear Bernd,
Thank you very much for your reply. I have a certain understanding of your answer, and I will further understand your answer according to relevant knowledge.I want to learn the influence of cooling rate on dendrite growth in the process of thin slab continuous casting. Just as you said, the cooling rate here refers to the temperature at the bottom of the simulation domain. Then what will be the influence of this cooling rate on dendrite growth in the simulation process?Do you have any suggestions for this cooling rate setting?
I am more grateful than I can express for your help.

Lv Shaojie

Bernd
Posts: 1221
Joined: Mon Jun 23, 2008 9:29 pm

Re: Cooling rate

Post by Bernd » Tue Apr 13, 2021 5:49 pm

Dear Lv Shaojie,

sounds as if you could use an approach like I did some years ago:

B.Böttger, M.Apel, B.Santillana, and D.G.Eskin

Relationship Between Solidification Microstructure and Hot Cracking Susceptibility for Continuous Casting of Low-Carbon and High-Strength Low-Alloyed Steels: A Phase-Field Study

Metallurgical and Materials Transactions A 44 5 (2013) 3765
DOI: 10.1007/s11661-013-1732-9

I have sent you the pdf as PM.

Bernd

shaojielv
Posts: 22
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Re: Cooling rate

Post by shaojielv » Wed Apr 14, 2021 3:58 am

Dear Brend,
I am very happy to get your help. I have received the article you sent me, and I will carefully read it. I would like to express my gratitude to you again and wish you a happy life.
Lv Shaojie

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