1. Thermo-Calc software package
Calculations of phase diagrams using
Thermo-Calc software package
Content
Equilibrium calculation using the Gibbs energy minimisation
1. The Gibbs energy for a system
2. The Gibbs energy for a phase
Unary system: Sn (calculation of melting temperature, plotting thermodynamic functions)
Phase diagram for the Sn-Bi system (Temperature - Composition)
Calculation of invariant reaction (T, phase compositions, enthalpy)
Calculation of thermodynamic properties of liquid phase
Calculation of phase fraction diagram for Bi concentration 5, 25 and 43 mol.%
Scheil solidification simulation for Sn-Bi alloys
Calculation of phase diagram for Fe-C system
Stable diagram
2. Metastable diagram

2. The Gibbs for a system and for a phasexB
1+3+5: G135=n1G1+n3G3+n5G5
1+2+4: G124=n1G1+n2G2+n4G4
1+3+4: G134=n1G1+n3G3+n4G4
2+4+5: G245=n2G2+n4G4+n5G5
2+4+6: G246=n2G2+n4G4+n6G6
2+3+5: G235=n2G2+n3G3+n5G5
3+4+6: G346=n3G3+n4G4+n6G6
3+5+6: G356=n3G3+n5G5+n6G6 xA

3. The Gibbs for a system and for a phase

4. The Gibbs for a system and for a phase

5. Property diagrams for unary system (Sn)
Tm=505 K (232°C)
L=Sn-Bct DHtr= kJ/mol

6. Phase diagram of the Sn-Bi phase diagram

7. Gm-curves for the Sn-Bi phase diagram

8. Calculation of enthalpy (DH) of reaction 1Liq=A(Sn)+B(Bi)
Stoichiometric coefficients A and B of invariant reaction are calculated by Lever rule b a
c=X(Bi) - X(Sn)
a=X(Bi) - XLiq
b=XLiq - X(Sn)
A=a/c
B=b/c
X(Sn) XLiq X(Bi)
DH(Tinv)=ADH(Sn)+BDH(Bi)-DHLiq
DH(412K)= kJ/mol-at.

9. Calculation of thermodynamic properties of liquid phase
Thermodynamic functions of mixing
(enthalpy, entropy, Gibbs energy) in Liquid phase at 300°C
Activity of Bi and Sn in Liqiud phase at 300°C

10. Phase fraction diagramsII
III I II
III

11. Scheil solidification simulation
D.R. Askeland, P.P. Phule
„The science and engineering of materials“
p. 370
ξ(liq)n – fraction of liquid calculated by lever rule at Tn

12. Scheil solidification simulation for Sn-5Bi alloy

13. Scheil solidification simulation for Sn-25Bi alloy

14. Scheil solidification simulation for Sn-43Bi alloy

15. Phase relations in the Fe-C system
Fig.1. Stable diagram
Fig. 2. Metastable diagram