The Property Model Calculator is a calculator within Thermo-Calc that offers predictive models for material properties based on their chemical composition and temperature. The Property Model Calculator is included with all Thermo-Calc installations, along with a general set of models for setting up some of the most common calculations, such as driving force, interfacial energy, liquidus and solidus temperature, and phase transition temperatures in general.
Users can buy additional packages of models or build your own models using the included Property Model Development Framework.
A Quick and Easy Path to Calculate Properties
The Property Model Calculator offers users a quick and easy path to calculate any ordinary property available from a Thermo-Calc calculation, for example, amount of phase, phase constitution, transition temperature, or similar. Furthermore, the calculator allows users to calculate additional properties using models that take the ordinary properties as input, such as coarsening rate coefficients, martensite start temperature, and yield strength. In addition, users can write and implement their own models utilizing the Property Model Development Framework, which is included in all Thermo-Calc installations.
Support for Materials Design
The Property Model Calculator has been developed to facilitate the design of materials. Consequently, it is easy to study how different variables influence defined properties of interest (or design variables) and to cross-plot the result to identify optimums in, for example, composition. Additionally, the Property Model Calculator gives users the ability to perform uncertainty or sensitivity analyses, for instance, to study how variations in chemistry influence a specific property.
Property Models are the engine that drive the Property Model Calculator. They simplify the process of setting up the calculations. They expand the functionality available in Thermo-Calc and make the software easier to use. Models can be used on their own or several can be evaluated simultaneously over a range of compositions to cross plot their results.
Models are Grouped within Libraries in the Software
The models are stored within libraries in the software, a library being a group of similar models. The software comes with a General Model Library, which includes models to help users to quickly set up some of the more common calculations using the Property Model Calculator. Users can also purchase libraries for specific materials or create custom models and develop your own libraries.
General Model Library
The General Model Library comes standard with all Thermo-Calc installations. It includes seven models to help users quickly set up some of the more common calculations using the Property Model Calculator:
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.
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.
General Model Examples
Thermo-Calc includes several examples to help you get started using the Property Model Calculator. All examples can be run in the Free Educational Package of Thermo-Calc.
PM_G_01: Phase Transition - predicts 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 Energy - uses 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 - This example 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 - This example 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, this 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 - This example shows the solid solution strengthening over the full solubility range for the Mo-Ta system as compared to experimental data.
Steel Model Library
The Steel Model Library includes three models for martensite and pearlite. The models are developed specifically for those who work with steels. The Steel Model Library is available for free to all users who have, or upgrade to, the thermodynamic and properties steel database TCFE version 9 or newer and the mobility steel databases MOBFE version 4 or newer, plus have a valid Maintenance and Support Subscription.
Users can develop your own models and seamlessly integrate them into Thermo-Calc using the Property Model Development Framework. In other words, you can customize the software to meet your modeling needs. The Property Model Development Framework is included with all Thermo-Calc licenses.
Models are developed using the easy-to-learn programming language Python™, and model development is possible without any additional installation using a simple editor, such as Notepad++. Users can also use a Python Integrated Development Environment (IDE) to access advanced features such as debugging of the Property Models and autocompletion.
Models are automatically encrypted for safe and secure file sharing. As of Thermo-Calc 2019a, any custom Property Models saved in Thermo-Calc can also be accessed using the TC-Python API.
Note that while this program uses Python and can be accessed from the TC-Python API, it does not require a license for TC-Python. It is included for free with all Thermo-Calc licenses.
Calculation Types Included in the Property Model Calculator
The Property Model Calculator includes the following calculation types:
Single - calculates a single point
One Axis - varies a quantity on the X-axis
Grid- evaluates two axis variables of the selected quantities in the specified range and number of steps.
Min/Max - evaluates the property model(s) for all variations of the selected quantities at the given limits. The Mean field is as defined under Condition Definitions for the respective quantity. The total minimum and maximum of the model(s) results are shown in the Event log.
Uncertainty Calculation - evaluates the Property Model(s) where the values of the quantities are sampled from Gaussian distributions. The Mean field is as defined under Condition Definitions for the respective quantity. The result is visualized as a histogram or normal probability plot by adding a Plot Render activity.
The Property Model Calculator is included for free with all Thermo-Calc installations. It comes with one set of general models. Additional, material-specific models can be purchased, or users can develop your own models using the included Property Model Development Framework. If you do not already have a license for Thermo-Calc or you are interested in expanding your license, please contact us to discuss which license is right for you.