thermodynamic questions...

issues about thermodynamics and their coupling to MICRESS
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crodriguez
Posts: 1
Joined: Sun Jan 25, 2009 11:18 pm

thermodynamic questions...

Post by crodriguez » Sun Jan 25, 2009 11:53 pm

Hi all..

MICRESS has its own database for example Nickel alloy database or MICREES used Thermocalc databases?
There is information published on the growth of gamma_prime and delta phase? ( I mean growth of Gamma prime and Delta phases in the Matrix, using Micress,)

Usually the model of Ostwald ripening is used for the growth of gamma_prime but not for delta phase, there is some consideration of this model for this phase?
the delta phase is on one dimension
Thank you in advance

Carlos

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

Re: thermodynamic questions...

Post by Bernd » Mon Jan 26, 2009 1:10 pm

Dear Carlos,

MICRESS can use all thermodynamic databases which can be used by Thermo-Calc, as MICRESS uses the Thermo-Calc fortran TQ interface. So, for Ni-base alloys, not only the database from Thermo-Calc AB can be used, but also e.g. the TTNI7 from Thermotech or any public database. We do not provide proprietary MICRESS databases!

The person who to my knowledge worked most with MICRESS and gamma_prime is Nils Warnken who formerly worked with us at ACCESS in Aachen. E.g.:

N. Warnken, D. Ma , M. Mathes, I. Steinbach
Investigation of eutectic island formation in SX superalloys
MATERIALS SCIENCE AND ENGINEERING A 413 12(2005)267-271

You may have a look on newer publications from him, he is working presently at the university of Birmingham. I myself worked a little on gamma_prime and eta phase, but I do not know of anyone who made phase-field simulation for the delta phase. Does this phase form needles like eta?
MICRESS does not use analytical models like the one from Ostwald, this comes out naturally if one sets up the simulation under the corresponding conditions. Do you plan to simulate ripening in Ni-base alloys with MICRESS?


Bernd

mogeritsch
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Re: thermodynamic questions...

Post by mogeritsch » Tue Aug 08, 2017 3:03 pm

Hi Bernd,

by using a database the log-file gives information about linearisation parameters of the phases XXX/YYYY. Some information are clear for me like TO, dG, dS, dH C0 and m. Unfortunately I don't understand the background of dcdT and the interaction matrix.

Could you give me a bit more details about this abbreviations?

Best regards,

Johann

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

Re: thermodynamic questions...

Post by Bernd » Wed Aug 09, 2017 12:52 pm

Dear Johann,

dcdT means the derivative of the equilibrium concentration with temperature. In MICRESS, apart from the concentration dependency given by the slopes m, C0 is regarded as T-dependent during extrapolation. The most recent literature reference on extrapolation methods in MICRESS is

B. Böttger et al. / Computational Materials Science 108 (2015) 283–292

You can see this derivative e.g. in Eq. 12. Tell me in case you have no access to the paper.

Bernd

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