hello dear khodaie,

indeed Thermo Calc result only prefer to  thermodynamic that occur in define condition (such ac certain chemical composition and defined pressure ,etc ). therefore  you cannot calculate T zero for a unknown condition, you can also contact to Thermo-Calc groupe to additional informations.

[email protected]

Kind rtegards

you can add the store energy of 400J/mol to bcc phase  using the following commands. 

Adv-opt

ph-add

bcc

400

Adv-opt list-ph-add

There is little problem in the literature, which I have pointed out in many times in our publications.  The work done on the system   due to applied surface tractions appears  with a positive sign to  u  and  f, respectively, energy and  Helmholtz free energy but  it has negative sign in the definition of  Gibbs free energy, g. These u, f, g  are volumetric specific energies.

g=u -Ts -  sigmaik epsilonik , Then one may writte the following expression

g=  uth - Ts   - 1/2  strain: stress  ( i,e., energy /volume)   uth  thermal part,  strain and stress are tensor quantities,  :  indicates the double inner product = sigmaik epsilonik  (Einstein sign convention). Similarly one may split the energy into thermal and strain energies (i.e.,linear elastic and hyperelastic solids): 

u= uth  +1/2sigmaik epsilonik   ,  f= uth +1/2sigmaik epsilonik - Ts  

Where it was assumed that the entropy is general doesn't depend on strain in most solids (Callen).

Thank you Guohong zhang. That is indeed the way.

Tarik, thank you. What you said got me thinking. I will get back to you on this.

Dear Nasseh,  Please Look at  the book entitled as  'the Foundation of Solid Mechanics by Y. C. Fung'' ,  Page,349 and Equation (8) for '' Gibbs Thermodynamic potential   Here,  Fung  has one problem,  he doesn't  consider explicitly the stored energy contribution to the thermodynamic energy U  in his  equation, which  is positive definite  and  1/2  strain: stress. Therefore net contribution to Gibbs free energy would be  -1/2 strain :stress.

See more rigorous treatment of this problem in the attached  article there, in addition I gave the contribution of stress  on the entropy.  Best regards 

Guohong's answer is the practical one and Tarik's answer gives you the theoretical background. In the pratical line of thinking, I would suggest you contact the people at the Interdisciplinary Centre for Advanced Materials Simulation (ICAMS) in Bochum, they have been doing Phase Field simulations on phase transformations and they have a lot of experience using ThermoCalc (their leader is Prof. Suzana Gomes Fries).  I think you could adapt Gibbs-Thompson theory to work with the strain energy, but htis is something of speculation. As for the theoretical background, I basically agree with Tarik, but I think you should be careful and consider only the deviatoric terms. In some thermocalc models (in particular, those used for steels) the PV term is included ad-hoc, so you should extract the hogeneous distortion energy from your formalism.

Dear Claudio,  If you look at our few papers related to the surface instabilities with growth term I was clearly showed two important points;

The first I proved that the stored strain energy term  in  isochoric system where Global Helmholtz free energy  variations should be negative for natural isothermal reaction  appears with negative sign, which oppose to the capillary potential  in the fundamental  equation proposed by Ogurtani, and causes inherent surface instability opposing to the capillarity under the applied electrostatic forces, which induced surface drift diffusion.  In the case of isobaric system, where external traction and body forces stays constant, and the  Global Gibbs free energy variations should be negative during isothermal natural processes, the stored energy term appears with positive sign , which is online with the capillarity, and it  enhances stability of surfaces exposed to electrostatic and elastostatic stresses.  In both cases we mentioned above, the   sign of the stored energy term is reverse  in their respective Helmholtz and Gibbs Free energy functions.

The secondly   I have proposed and showed that there is a another type of strain field interaction as originally proposed by Kröner for the bulk system, between diffusion atomic species at   the surface layer and the local stress field induced by external or internal  agents, which is called the elastic dipole tensor interaction.

Most important out come of this new interaction force is that its sign depends on the whether one has uni and  bi-axial tension or compression acting as a hoop stress on the diffusing  surface atomic species. Even In the case of free surface conditions, the surface atoms are experiences  2D hoop stresses, which have by definition  no components on the surface plane   sigma. surface normal=0.  

This new scenario  fundamentally affected our   perception and interpretation of  the events  taking place during evolution of surfaces and interfaces  with and without, respectively,  the external excitation such electrostatic and electrostatic forces, or but having internal stress raisers, misfit strains etc.