FactSage contains many modules. The major ones for daily work are Equilib and Phase Diagram.
In the Equilib module, global Gibbs energy minimization is used to determine the equilibrium state of a complex chemical system defined by its chemical composition, temperature and pressure. Equilib is easy to use: First, the chemical system has to be defined in the Reactants window:
As it can be seen, reactants can be defined in various ways: By inserting the mass or the molar amount, or even by a combination of both. Additionally, elements (Fe. Cr. Ni. C) can be used as well as chemical formulae (N2, O2).
Next, the calculation conditions have to be specified in the Menu window:
The user can choose the possible products to be considered in the calculation. If you are interested in the thermodynamic equilibrium, you can simply choose all possible products. If you want to suppress a phase since you are sure that it does not form due to limited reaction kinetics (e.g. Graphite in the Fe-C system), you can simply omit the phase from the calculation. Chemical equilibrium can be calculated for a system that is defined with regard to temperature, pressure (or volume), enthalpy and total amounts and/or equilibrium activities of any phase constituent in the system. Several calculations can be done at once, where e.g. temperature is varied. In the figure above, temperature is varied between 500 and 1000°C with a step size of 50°C, resulting in 11 calculations. Other conditions for an equilibrium can also be set, for example that a certain phase is formed when temperature or composition changes or a Scheil cooling curve.
The result is first presented in a simple table and can be used in the integrated postprocessor to prepare a graphical output. Of course, the results can also be exported to other applications, e.g. into an Excel® spreadsheet. Below is a (shortened) results table and a screenshot of the Figure module. As example, the amounts of all stable phases is shown as function of temperature.
Do you want to try a simple web-based Equilib calculation? Use the demo Equilib-Web feature developed by our partners at ThermFact/CRCT!
Interested in further information? Check out the information about Equilib on factsage.com!
*T = 881.94 C P = 1 bar V = 0 dm3 STREAM CONSTITUENTS AMOUNT/gram Fe 8.2000E+01 Cr 1.8000E+01 Ni 1.0000E+01 C 5.0000E-02 EQUIL AMOUNT MASS FRACTION ACTIVITY PHASE: FCC_A1#1;#2;#3 gram CrC 4.6472E-02 4.2228E-04 3.5275E-03 FeC 2.0897E-01 1.8988E-03 1.2011E-05 NiC 2.5265E-02 2.2958E-04 1.6154E-06 Cr1Va1 1.7962E+01 1.6322E-01 1.9528E-01 Fe1Va1 8.1828E+01 7.4355E-01 7.4085E-01 Ni1Va1 9.9790E+00 9.0677E-02 5.5347E-02 TOTAL: 1.1005E+02 1.0000E+00 1.0000E+00 Site fraction of sublattice constituents: Cr 0.17441 Stoichiometry = 1 Fe 0.73976 Ni 8.5836E-02 ------------------------------------------------------------------- C 2.0973E-03 Stoichiometry = 1 Va 0.99790 System component Mole fraction Mass fraction Ni 8.5657E-02 9.0868E-02 Fe 0.73821 0.74512 Cr 0.17404 0.16356 C 2.0929E-03 4.5434E-04 Neel temperature = -195.08 C Average magnetic moment/atom = 0.26357 PHASE: M23C6 gram MASS FRACTION ACTIVITY Cr20Cr3C6 0.0000E+00 5.9723E-01 2.1437E-03 Fe20Cr3C6 0.0000E+00 1.8366E-01 3.1322E-15 Ni20Cr3C6 0.0000E+00 6.1375E-03 1.0076E-41 Cr20Fe3C6 0.0000E+00 1.5428E-01 3.5964E-05 Fe20Fe3C6 0.0000E+00 4.7420E-02 5.2548E-17 Ni20Fe3C6 0.0000E+00 1.5841E-03 1.6903E-43 Cr20Ni3C6 0.0000E+00 7.3548E-03 3.8193E-09 Fe20Ni3C6 0.0000E+00 2.2598E-03 5.5805E-21 Ni20Ni3C6 0.0000E+00 7.5471E-05 1.7951E-47 TOTAL: 0.0000E+00 1.0000E+00 1.0000E+00 Site fraction of sublattice constituents: Cr 0.76969 Stoichiometry = 20 Fe 0.22315 Ni 7.1542E-03 ------------------------------------------------------------------- Cr 0.78857 Stoichiometry = 3 Fe 0.20187 Ni 9.5597E-03 ------------------------------------------------------------------- C 1.0000 Stoichiometry = 6 System component Mole fraction Mass fraction Ni 5.9228E-03 7.8233E-03 Fe 0.17478 0.21966 Cr 0.61240 0.71660 C 0.20690 5.5923E-02 PHASE: BCC_A2#1;#2 gram MASS FRACTION ACTIVITY CrC3 0.0000E+00 4.5556E-05 2.7455E-26 FeC3 0.0000E+00 1.4678E-04 9.4888E-26 NiC3 0.0000E+00 9.2878E-06 5.8584E-26 Cr1Va3 0.0000E+00 2.2074E-01 4.2513E-01 Fe1Va3 0.0000E+00 7.3185E-01 7.4303E-01 Ni1Va3 0.0000E+00 4.7209E-02 3.4267E-02 TOTAL: 0.0000E+00 1.0000E+00 9.7882E-01 PHASE: LIQUID#1;#2 gram MASS FRACTION ACTIVITY Fe 0.0000E+00 6.7127E-01 4.4644E-01 C 0.0000E+00 2.4320E-03 7.1279E-07 Cr 0.0000E+00 2.6170E-01 1.3307E-01 Ni 0.0000E+00 6.4592E-02 3.1027E-02 TOTAL: 0.0000E+00 1.0000E+00 7.2799E-01 PHASE: CEMENTITE gram MASS FRACTION ACTIVITY Cr3C 0.0000E+00 8.1418E-01 2.6015E-01 Fe3C 0.0000E+00 1.8282E-01 3.4403E-03 Ni3C 0.0000E+00 2.9944E-03 3.7805E-07 TOTAL: 0.0000E+00 1.0000E+00 4.5825E-01 ******************************************************************** Cp H S G V J.K-1 J J.K-1 J dm3 ******************************************************************** 6.70694E+01 6.76446E+04 1.58581E+02 -1.15530E+05 0.00000E+00 Cut-off limit for phase activities = 1.00E-75 Databases: FSstel 7.0, FactPS 7.0 Data Search options: exclude gas ions; organic CxHy.. X(max) = 2; min soln cpts = 2
