phase transformation

solid-solid phase transformations, influence of stresses and strains
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Jane
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phase transformation

Post by Jane » Fri Jul 29, 2022 1:38 pm

In the process of phase transition, the problem shown in the figure began to appear with time, but I did not find the reason for this phenomenon, and I look forward to your answer.

Jane
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PHASE TRANSFORMATION.png
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Bernd
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Joined: Mon Jun 23, 2008 9:29 pm

Re: phase transformation

Post by Bernd » Fri Jul 29, 2022 5:32 pm

Dear Jane,

What is clear from the picture you show is that the interfaces between phase 1 and 2 are completely destroyed. I cannot tell you more without having more information about the system and the used input parameters...

Bernd

Jane
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Re: phase transformation

Post by Jane » Mon Aug 01, 2022 5:53 pm

Dear Bernd,

First of all, thank you for your reply, I will attach my driver file, please check it, I hope you can answer the reasons for some errors for me.

Jane
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Acicular.dri
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Bernd
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Re: phase transformation

Post by Bernd » Mon Aug 01, 2022 7:13 pm

Dear Jane,

Do you use BCC_A2 or BCC_B2 phase? Please send a clean .in file, otherwise the comments are wrong, and I cannot see what you are doing...

Bernd

Jane
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Re: phase transformation

Post by Jane » Tue Aug 02, 2022 4:26 pm

Dear Bernd,

Sorry, the following is the clean file I created, please check it out.

Jane
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Acicular -.dri
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Bernd
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Re: phase transformation

Post by Bernd » Tue Aug 09, 2022 11:25 pm

Dear Jane,

Sorry for my late reply, I am currently on holidays. I have checked you simulations and noted that nucleation is not working correctly with version 7.000, while everything is fine with 7.003 and 7.1. Do you have access to 7.003? Otherwise you should ask Ralph how you can get one.

Bernd

Jane
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Re: phase transformation

Post by Jane » Thu Aug 11, 2022 5:25 pm

Dear Bernd,

First of all, thank you for your reply. It should be noted that I use 7.003, but the interface problem I mentioned will appear, but you said that you can run normally, I am very strange.

Jane

Bernd
Posts: 1438
Joined: Mon Jun 23, 2008 9:29 pm

Re: phase transformation

Post by Bernd » Tue Aug 16, 2022 7:15 pm

Dear Jane,

You can find the exact version number and compilation date at the top of the .in output file which is created when you run your simulation.

However, I focussed on the wrong error: With version 7.000 I did not get nucleation while I got it with newer versions. But your error occurs later...

Meanwhile I identified two other potential problems:

1. You use the full diffusion matrix for fcc and bcc ("multi ggg") together with "nple" redistribution behavior. This combination is prone to create numerical problems, because the nple-Model implies unrealistic concentration steps for the corresponding elements (see .cpha output). These steps lead to unrealistic cross diffusion of C which then may lead to numerical problems. I recommend using "diagonal g" for diffusion of all elements in both phases.

2. Given the total simulation time of 300s and the cooling rate of 2K/s, the simulation runs into temperature ranges where C-diffusion is very low and grid resolution is too low to resolve the C-pile-up. This will lead to wrong behaviour towards the end of the simulation.

Bernd

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