Dendritic growth not observed

dendritic solidification, eutectics, peritectics,....
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Yongliang Ou
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Dendritic growth not observed

Post by Yongliang Ou » Thu Apr 15, 2021 10:08 am

Dear Bernd,

Recently I try to simulate one solidification process with which the dendritic growth is expected. However, results show planar growth. I tried to modify the following parameters:
  • Smaller grid spacing: 0.01 μm
  • Different kinetic coefficients: 0.1, 1, 5, 10
  • Smaller interval for updating diffusion coefficients: 1E-06
but still only planar growth was observed.

I would like to ask if any other parameters affect the growth mode and how should I set them correctly? Attached please kindly find the driving file and the corresponding GES file. Thanks in advance!

Best regards,
Yongliang Ou
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AlSiMg.GES5
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09_lpbf_4a.in
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Bernd
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Joined: Mon Jun 23, 2008 9:29 pm

Re: Dendritic growth not observed

Post by Bernd » Thu Apr 15, 2021 2:26 pm

Yongliang Ou,

Most probably, the interface mobility is reduced due to a too high value of the minimum time step. Please note that the definition of a minimum time step is done for performance reasons only and cannot be done before the setup of the simulation is finished successfully. Time stepping can be monitored in the .TabT file, which is one of the tab_log outputs. Please also note that you will need to decrease the time interval for tab_log outputs in order to get any information in these files.

Please also note the following:

- in view of the huge cooling rate which you apply, the applied grid resolution of 0.01 µm may still be too coarse
- given the high velocity of the solidification front, even a mobiity value of 1.0 cm**4/(Js) max still be insufficient to reach diffusion controlled growth

Bernd

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