Simulation with dG dependent mobility

solid-solid phase transformations, influence of stresses and strains
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nokkikku
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Simulation with dG dependent mobility

Post by nokkikku » Mon Nov 28, 2011 5:09 pm

Hallo there,

according to the example file of dG dependent simulation (which it was for austenite grain growth on download area. And it seems that it disappeared from there now.), we can specify the interface mobility manually dependent on the current dG value. I have the following questions:

1. if we put some value points, will the mobility values inbetween the given points be intrapolated? and how?
2. the field value shown by DP_MICRESS from .driv file should be in J/cm^3 unit, right?
3. I saw some positive dG value at the interface area between ferrite and ferrite. What does it mean?

Thank you in advance,
nokkikku

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

Re: Simulation with dG dependent mobility

Post by Bernd » Tue Nov 29, 2011 4:39 pm

Hi nokkikku,

The example files disappeared without intention from the homepage, there was a link missing...
Anyway, they have to be replaced by the new files for MICRESS 6.0. This will be done soon!

Here are the answers to your questions:
1.) Yes, the mobility values will be interpolated linearly with the driving force. Outside the range of data, extrapolation will be performed. Thus, if you want to have constant mobility values outside the given range you have to specify the mobility twice, e.g.:

#dG [J/cm**3] mue [cm**4/(Js)]
-2.000E-3 0.00500
-1.500E-3 0.00500
-1.400E-3 0.000100
-0.000 0.000100
+1.400E-3 0.000100
+1.500E-3 0.00500
+2.000E-3 0.00500

If you would omit the first and last line, the extrapolated mobility values would be very large for high values of dG! To be sure whether things work correctly, it is wise to have a look on the mobility (.mueS) and driving force output (.driv).

2.) Right! But there is some difference between dG as defined in the .driv output and dG in the input for dG dependent mobility: The .driv output contains the contributions of concentration, temperature, recrystallisation and stress on the driving force, dG in the dG dedendent mobility input also the curvature contribution!

3.) Between same phases you should see only driving forces in the .driv output, if recrystallisation is activated and the grains have different reX energy... May it be that there are traces of another phase trapped inside the interface?

Bernd

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