Columnar to Equiaxed Transition (CET) Property Model Settings

The Columnar to Equiaxed Transition Property Model calculates the fraction of equiaxed grains that correlates with a certain solidification condition, specifically thermal gradient (thermal gradient) and solidification growth rate (solidification growth rate).

This General Model is available when using the Property Model Calculator in Thermo‑Calc.

For theory, see About the Columnar to Equiaxed Transition (CET) Property Model.

For examples see:

System Definer Configuration Settings

Use of this Property Model requires mobility data of liquid for the calculations. For all simulations both a thermodynamic and a mobility (kinetic) database must be selected on the System Definer.

Property Model Calculator Configuration Settings

The settings are found on the Property Model Calculator when the Columnar to Equiaxed Transition Model is selected under General Models.

When working in the Configuration window, click the Description tab for more information about the Model.

For the details about the Condition Definitions, Calculation Type, Timeout in minutes, Parallel Calculation, and other calculation associated settings, see Property Model Calculator: Configuration Window Settings.

Select the Primary phase from the list. This is the primary solid phase to form the dendrite.

Enter a value for the Interfacial energy [J/m^2], which is between the liquid and primary phase. The default is 0.25 J/m2.

Enter a value for the Number of nucleation sites [/m^3] for equiaxed grains per cubic meter. The default is 2.0E15 / m3.

Enter a value for the Nucleation undercooling [K], which is the critical undercooling for nucleation of equiaxed grains. The default is 2.5 K.

Enter a value for the Equiaxed exponent. The Equiaxed exponent is used in the equation that calculates the fraction of equiaxed grains. This is usually a value between 3 and 5.

Select an option from the Solve for list (Equiaxed fraction or Thermal gradient) and then enter the required secondary information as indicated.

  • Equiaxed fraction: Solve for the equiaxed fraction given the thermal gradient. When Equiaxed fraction is selected, then enter a value for the Temperature gradient, which is the temperature gradient of the liquid ahead of the dendrite tip. The default is 1000 K/m.
  • Thermal gradient [K/m]: Solve for the thermal gradient given the equiaxed fraction(s). When Thermal gradient is selected, then enter a value for the Equiaxed fractions. This finds the thermal gradient for the given equiaxed fractions. The values entered should be between 0.001 and 0.99. If more than one fraction, separate the values with a space. The default is 0.0066 0.49 0.99.

Select a Growth rate from the list then enter a value in the field.

  • If v is selected, then enter a value for the solidification growth rate, v. The default is 0.1 m/s.
  • If log10(v) is selected, then enter a value for the logarithm of growth rate, log10(v). The default is -1.0 m/s.

Select the Solute trapping checkbox to enable solute trapping at the tip interface. By default this is not selected.

Plot Renderer Settings

Plot Renderer and Plot Renderer: Configuration Settings

When setting up your calculation on the Plot Renderer and/or Table Renderer, the following axis variables are available for the conditions defined on the Property Model Calculator.

When selecting quantities on the Plot Renderer or Table Renderer, the quantity names include an abbreviated name for the Property Model it is associated to. This is useful in particular when you are calculating two or more Property Models that share names for the quantities. The short name identifying the specific Property Model is included in parentheses after the name of the quantity. Below are the full and abbreviated names for each Property Model.

For a list of the abbreviations associated to a Property Model, see Result Quantities: Property Model Abbreviations.

Select from these plot quantities:

  • log10(v) [m/s]
  • Liquidus
  • Fraction of equiaxed grains
  • Tip radius
  • Thermal gradient
  • Solidification rate
  • Dendrite tip undercooling [K]