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13 votes

What thermodynamic data is collected in order to build a CALPHAD model?

I concur with the answer by Alone programmer, but his answer only gives half the story. The coefficients or the model parameters come into the picture later and are actually obtained by optimization ...
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11 votes

What thermodynamic data is collected in order to build a CALPHAD model?

Basically you need to find $L_{ij}^{m}$ coefficients in the Redlich-Kister polynomials from DFT calculations, related to temperature as: $$L_{ij}^{m} = a_{ij}^{m} + b_{ij}^{m} T + c_{ij}^{m} T \ln(T) ...
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8 votes
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Pycalphad "Failed while parsing" Yttrium from light alloys database

Thanks to Tyberius for pointing out one issue in the database in their comment. The pycalphad database parser is strict, but also tries to prevent ambiguities or mistakes. I made the following ...
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7 votes
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Pycalphad most efficient way to gather equilibirum phase data for set of alloy compositions?

In your comment, you mentioned that you may be testing many alloys (100,000s). I will assume that interested in taking more of a screening approach, rather than specifying precisely 100,000 alloys ...
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6 votes

For a Thermo-Calc database, is it possible to view the equation/parameters of the Gibbs free energy models?

I am not sure about TC-Python but in console mode, you can access the Gibbs energy equations directly using the Gibbs Energy System (GES) module. In case you need the details about a particular phase ...
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6 votes
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Is it possible to analytically solve for a particular phase region of a CALPHAD database? (instead of guessing and checking)

if you had access to the database equations for a given alloy system, could you analytically solve (and thus solve quickly) for the conditions (i.e., temperatures and compositions) that would produce ...
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5 votes
Accepted

Thermo-Calc: how to suspend specific composition sets?

Thermo-Calc creates new composition sets from the global minimization process and you cannot, to my knowledge, have direct control of preventing certain composition sets from being created. Disabling ...
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5 votes

Thermo-calc: Calculate precipitation driving force by parallel tangent construction

Thermo-Calc's DGM is the normalized parallel tangent driving force per mole of components. To be able to compute the driving force of a phase, it must be set to &...
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5 votes

What information about a crystalline solid material goes into calculating phase diagrams in Thermo-Calc, and how?

Enthalpy and entropy are the temperature dependent terms in free energy from which enthalpy is a dominant term mainly at lower temperature and entropy is dominant at higher temperature (because ...
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5 votes
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How to get order constitution data for single equilibrium calculation in Thermo-Calc's TC Python module?

I don't have access to TC-Python, so I can't offer advice on how to use the API specifically. This is more of a workaround than a direct way to get Thermo-Calc to tell you whether the phase is ordered ...
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5 votes

What thermodynamic data is collected in order to build a CALPHAD model?

As a retired professor in Computational Thermodynamics I am happy that young students try to use the Calphad methods to understand materials. However, to model a phase using Calphad there are some ...
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