# General Models

## Seven General Models are included in Thermo-Calc to help users to quickly set up some of the more common calculations using the Property Model Calculator.

#### General Property Models Available in Thermo-Calc

• Coarsening Model - calculates the coarsening rate coefficient K (m3/s) of a spherical precipitate phase in a matrix phase.
• Phase Transitional Model - calculates the point when a new phase may form by varying set conditions. The model is useful to determine melting temperature, boiling temperature or solubility limits. It returns the phase transformation temperature, or composition, depending on the varied condition.
• Driving Force Model - calculates the thermodynamic driving force for a phase.
• Interfacial energy model - estimates the interfacial energy between a matrix phase and a precipitate phase using thermodynamic data from a CALPHAD database.
• Equilibrium Model - calculates the equilibrium for the given conditions. Optionally define additional Function Definitions.
• Liquidus and Solidus Model - this model offers a fast and easy way to complete this common calculation. For example, you can easily use uncertainty calculations, varying one or more conditions, and see how that affects the liquidus and solidus temperatures. It is available in Thermo-Calc 2017a and newer.
• Yield Strength Model - considers four contributions to the overall yield stress of the material - intrinsic strength for the pure elements, grain boundary strength, solid solution strengthening and precipitation strengthening. Yield strength is also available as a plot/table variable when working with the Precipitation Calculator. This is a powerful feature when used with the Add-on Precipitation Module (TC-PRISMA) because it can make use of the particle size distribution coming from a nucleation and growth simulation to predict the yield strength as a function of heat treatment time-temperature profile Users can evaluate models simultaneously over a range of compositions and cross plot the results, then conduct an uncertainty analysis and plot the results as either a histogram (as shown below) or as a probability plot.

#### General Model Examples Available in Thermo-Calc

Thermo-Calc includes the following examples to help you get started using the Property Model Calculator. All examples can be run in the DEMO version of Thermo-Calc:

• PM_G_01: Phase Transitionpredicts the transition temperature to the unwanted brittle σ-phase and shows how the temperature is influenced by changes to a steel alloy’s composition using the uncertainty calculation type and either a histogram or probability plot.
• PM_G_02: Coarsening and Interfacial Energyuses the Property Model Calculator and both thermodynamic (FEDEMO) and kinetic (MFEDEMO) demonstration steel databases to calculate the coarsening rate and interfacial energy of the carbide M23_C6.
• PM_G_03: Driving Force and Interfacial Energy - uses the grid calculation type to produce a contour plot comparing the driving force and interfacial energy of the carbide M23C6.
• PM_G_04: Yield Strength - compares the Simplified and Seidman models yield strength versus precipitate radius to experimental data for an Al-0.3wt%Sc alloy.
• PM_G_05: Yield Strength_NiAlCr - using the Reppich model, the example shows a calculation of the precipitation strengthening vs precipitate radius in a Ni-10at%Al-10at%Cr alloy
• PM_G_06: Yield Strength_HEA - shows the solid solution strengthening over the full solubility range for the Mo-Ta system as compared to experimental data.

#### Open the Examples and Search for Information in the Thermo-Calc Help

To open the example files described above, go to Help > Example Files > Property models > General. Double click on any of the files to load them into Thermo-Calc.

You can also find more information about the Property Models in the Help included with your software. From within Thermo-Calc, press F1 or from the menu select Help > Online Help and then search for Property Model Calculator or any other search term relevant to your query. You can access the examples from the Help menu in Thermo-Calc.

#### General Model Examples Videos

Videos have been made for each of the General Model examples showing users how to set up the calculations and what the results mean.

View the videos on our YouTube page »