input of static anisotropy changed!

technical aspects of .dri file generation (e.g. debug mode ) etc...
Rody
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Re: input of static anisotropy changed!

Postby Rody » Wed Apr 14, 2010 6:03 pm

Hi janin,

Can you explain how delta1 and delta2 work in 3D simulation as you showed in 2D upstairs?
Thanks!

Kind regards
Rody

janin
Posts: 22
Joined: Thu Oct 23, 2008 3:06 pm

Re: input of static anisotropy changed!

Postby janin » Fri Apr 16, 2010 2:56 pm

The 3D formulation is similar to the 2D, but stretches the classic cubic formula in both y and z directions.
The user specifies as before the value of delta1 and additionally the values of deltaXY and deltaXZ in the input file.
The standard cubic formulation in 3D is
a = a0 * (1-4*delta1 * ( n_x^4+n_y^4+n_z^4 -0.75)
where n is the interfacial normal vector.
This value is then multiplied by the elongation factor:
elongation_factor = 1 + n_y^2 * (deltaXY - 1) + n_z^2 * (deltaXZ - 1).
Regards,
Janin

Lilly
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Re: input of static anisotropy changed!

Postby Lilly » Sat Sep 09, 2017 4:52 am

Hi Janin,

I have some problems about standard cubic formulation and Elongation_factor in 2D.

In the standard function of Delta1, does cos(n*theta) mean n×theta or the same as described in 3D. And what does cos(theta)**2 mean? What does "**" mean?

Kind regards
Lilly

janin
Posts: 22
Joined: Thu Oct 23, 2008 3:06 pm

Re: input of static anisotropy changed!

Postby janin » Mon Sep 11, 2017 12:20 pm

Hi Lilly,
in the driving file we can only use ascii code. Therfore we use the star symbol instead of a dot for multiplication:
a*b means a multiplied by b.
Moreover we use two stars for exponentation:
a**b denotes raised to the power of b.

Anyway, I would recommend to have a look at the Micress manual, volume 2, section 4.8.3 on page 81.
Here you can find a table with all anisotropy equations in proper notation.

Janin

Lilly
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Joined: Mon Sep 04, 2017 5:02 am
anti_bot: 333

Re: input of static anisotropy changed!

Postby Lilly » Fri Sep 15, 2017 4:30 pm

Hi janin,

Thanks very much! I want to simulate morphology of primary silicon, can I use the facet model? And Can you give me some literatures for derivation of facet model?

Thanks!

Lilly

janin
Posts: 22
Joined: Thu Oct 23, 2008 3:06 pm

Re: input of static anisotropy changed!

Postby janin » Thu Sep 21, 2017 6:57 pm

Yes,
the facet model is the best choice to simulate primary silicon.
You can find the description of the input parameters in the Micress manual, volume 2, section 4.5.2, page 70
and the respective equations in section 4.8.3, pages 82/83.

Moreover, I recommed a recent paper about Micress simulations of primary silicon growth in AlSi-alloy by
K. Wang, M. Wei, L. Zhang, and Y. Du:
Morphologies of Primary Silicon in Hypereutectic Al-Si Alloys: Phase-Field Simulation Supported by Key Experiments
Metallurgical and Materials Transactions A 47A (2016)1510 DOI: 10.1007/s11661-016-3358-1

In this paper you can also find further references.

Regards,
Janin


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