Facetted crystals

dendritic solidification, eutectics, peritectics,....
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Nils
Posts: 3
Joined: Tue May 26, 2009 11:30 am

Facetted crystals

Post by Nils » Wed May 27, 2009 2:09 pm

Hi Everybody out there using MICRESS,

I have recently tried to simulate facetted crystal growth, but somehow I can't figure out what the parameters in the driving file mean. The information in the MICRESS manual is also a bit scarce. So how to set up a number of facetts in a MICRESS simulation? And what do the anisotropy parameters in the phase-interaction section mean? How many facetts have to be described in minimum? Is it possible to do for example somethings like this:

/\
||
||
||
\/

(needle like, with two parallel sides and two tips)
Or this:

/-\
| |
| |
| |
\-/

or even more complicated.

Thanks for your help.
Cheers
Nils

Bernd
Posts: 1505
Joined: Mon Jun 23, 2008 9:29 pm

Re: Facetted crystals

Post by Bernd » Wed May 27, 2009 2:28 pm

Hi Nils,

In principle, it should be possible to simulate the structures you propose. About the input structure and meaning of the parameters there has been already a thread!

Needles are generally problematic, because the characteristic of a needle is that it does grow only in certain directions. This, on one hand, is problematic with the facetted model, therefore I recently defined an "antifacetted" model which works contrarily to the facetted model. On the other hand, even with the antifacetted model, directions in phase-field models are always diffuse, and thus is is practically impossible to get needles without lateral growth (if they are not growing exactly in grid direction...).

Please tell me if you need further information!

Bernd

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