# Thermo-Calc 2024a Available Now

Introducing Thermo-Calc 2024a, released in December 2023. This release features several updates to the Additive Manufacturing Module, a new Parallel Coordinates plot type for Materials Design, and four new Property Models for a variety of applications. This release also includes six new databases, including our first ever database for molten salts. Additionally, electrical conductivity of ionic liquids has been added to the TCOX database, meaning that the database can now calculate electrical conductivity and electrical resistivity for any slag composition.

## Webinar on Thermo-Calc 2024a Release

Watch our on-demand release webinar to learn about the exciting new features and new databases included in Thermo-Calc 2024a. In this webinar, the developers who worked on the release will speak directly about these exciting new developments.

The Additive Manufacturing Module, or AM Module, received two major new features in this release, and is now available in TC-Python.

## New Keyhole Model

A keyhole model has been introduced in the AM Module. In additive manufacturing, when the laser beam intensity is high, which is often done to increase productivity, evaporation of liquid metal creates a recoil pressure that pushes down the liquid to form a cavity, which is called a keyhole. You can see this demonstrated on the right side of the image below.

A representation of the additive manufacturing process comparing the effects of low and high laser beam intensity. High energy (right) creates a recoil pressure that pushes down the liquid to form a cavity, which is called a keyhole.

The Additive Manufacturing Module now includes a model that computes the keyhole shape and corresponding mesh that is used for the steady-state simulation. The model also includes the effect of multiple reflections of the laser beam on the keyhole walls.

From example AM_06b, this Steady-state temperature distribution around the melt pool for SS316L with P = 80 W and scanning speed = 400 mm/s using the calibrated Gaussian heat source with the keyhole model. A keyhole can also be seen formed just below the location of the heat source.

## Calibrate Volume Heat Source Parameters Using Experimental Melt Pool Data

A Heat source calibration option has been added to the AM Module in order to improve the ability to predict the melt pool size under various process conditions. This new feature allows users to import experimental melt pool data for a range of processing parameters.

A screenshot from the AM Module in Thermo-Calc showing imported experimental melt pool data for the new Heat source calibration feature.

Users can calibrate the heat source parameters to match the experimental data for your material and processing conditions. Once you have finished the optimization, you can plot the Heat calibration parameters and the Melt pool dimensions as a function of energy density (power/scan speed) and select a function for each heat source parameter.

Heat calibration parameters for a double ellipsoidal calculation.

The Heat source functions can be saved as a user-defined heat source, which will be available from the heat source menu.

Two examples are included in the software demonstrating this new feature:

• AM_06a_Calibrate_Heat_Sources_316L
• AM_06b_Use_Calibrated_Heat_Sources_316L - can be run without a license for the AM Module

## Additive Manufacturing Module Now Available in TC-Python

The AM Module is now available in TC-Python and includes nearly all the functionality included in Thermo-Calc. This addition allows users to easily perform simulations over a large range or process parameters and to produce printability maps for when defects like lack-of-fusion, keyholing, and balling will occur.

Six new examples are included in TC-Python demonstrating the AM Module. Users who do not have a license for the AM Module can run AM examples 1 through 4 and 6b.

## New Columnar to Equiaxed Transition (CET) Property Model

Another valuable addition for Additive Manufacturing users and for those of you working with casting is the new Columnar to Equiaxed Transition Property Model. This Property Model calculates the fraction of equiaxed grains that correlates with a certain solidification condition, specifically thermal gradient (G) and solidification growth rate (v). This provides valuable information on the solidification microstructure.

Three new examples are included in the release demonstrating this new model:

• PM_G_15_Ni-Al-Cr_Columnar_Equiaxed_Transition - CMD-1333
• Uses NIDEMO and MNIDEMO databases, which are available to all users
• PM_G_16_CMSX-4_Columnar_Equiaxed_Transition
• PM_G_17_IN718_Columnar_Equiaxed_Transition
• These examples both use the TCS Ni-based Superalloys Database (TCNI) and TCS Ni-alloys Mobility Database (MOBNI), which require additional licenses. This is so these examples can better show results using known alloys compared to experimental data

One of the plot results from example PM_G_15 where the CET curves for a Ni-26Al-9Cr alloy are plotted compared to experimental data. In this example, the nickel demo databases are used, which are available to all users.

## New Parallel Coordinates Plot Type

For those working with Materials Design, a new Parallel Coordinates plot type is introduced in the Property Model Calculator

Screenshot of the new Parallel Coordinates plot type is introduced in the Property Model Calculator.

The Parallel coordinates plot is useful when interpreting multidimensional data and to compare how different parameters affect each other. This is especially useful in materials design after performing a batch or uncertainty set of evaluations when multiple inputs are varied at the same time and multiple model outputs are given as a result.

##### Interpreting results of the plot:
• When most lines between two parallel axes are somewhat parallel to each other, there is a positive relationship between these two dimensions.
• When lines cross in a kind of superposition of X-shapes, there is a negative relationship between these two dimensions.
• When lines cross randomly, it means that there is no particular relationship.

The new plot type is used with the Property Model Calculator and either the Grid, Batch, or Uncertainty Calculation Type.

A new example is included in the release demonstrating this plot type:

• PM_Ni_04_Strain_Age_Cracking

## New Scheil Property Model

A new Scheil Property Model is available for all users of Thermo-Calc. This new Property Model is essentially the same as the Scheil Calculator already included in the software, but implementing Scheil as a Property Model allows users to benefit from the additional calculation types available in the Property Model Calculator, including multi-axis Grid, Min/Max, Uncertainty, and Batch.

A heat map of the Freezing range from a Scheil calculation for an Al-1Si-1Mn-0.7Mg-0.6Fe-0.1Cu alloy using the new Scheil Property Model with the grid calculation type.

## Crack Susceptibility Coefficient Property Model Improved

The Crack Susceptibility Coefficient Property Model received two new models in this release. In addition to the original Clyne and Davies model, you can now select Kou or Easton models.

Screenshot of the settings in the Crack Susceptibility Coefficient Property Model, showing all the models including the new Kou and Easton models.

The Model also received additional Scheil settings. For example, users can now select Scheil with Back Diffusion in Primary Phase or Scheil with Solute Trapping, in addition to Classic Scheil. The Advanced Scheil Options have also been expanded in the Property Model.

## Yield Strength Model Improved

The intrinsic strength model has been completely overhauled in order to improve the Yield Strength Model. Previously, intrinsic strength was only calculated per element and only for FCC, BCC, and HCP. Now, the model formulation corresponds to a surface of reference with end-members.

The plot shows how the intrinsic strength of FCC_A1#2 (in this case TiC) is accurately calculated with increasing volume fraction.

This change enables accurate modeling of the strengthening effect to:

• Interstitial elements
• Stoichiometric and non-stoichiometric compounds in addition to solid solution phases

For example, it is now possible to calculate yield strength for materials with a significant fraction of hard phases, such as carbides, embedded in a soft matrix.

## New Martensitic Steel Strength Property Model in the Steel Model Library

The Steel Model Library introduces one new Property Model, Martensitic Steel Strength, which calculates the yield strength and/or hardness of martensitic steels.

A new example is included in the release demonstrating this new model:

• PM_FE_10_Martensitic_Steel_Strength

The plot shows the tempering temperature compared to the total hardness of three tempered AISI steels (1030, 1095 1144) compared to handbook data from Penha, et al. (2013), calculated using the new Martensitic Steel Strength Property Model.

## New Strain-Age Cracking Property Model in the Nickel Model Library

The Nickel Model Library also introduces a new Property Model, Strain-Age Cracking, which is used in applications related to welding and additively manufactured components where there are interface strains between γ’ (gamma prime) and the matrix.

A new example is included in the release demonstrating this new model:

• PM_Ni_04_Strain_Age_Cracking

Parallel plot of the SAC risk factor along with experimental and calculated solvus of γ’ for the three alloys compared in [2020Zho], calculated using the new Strain-Age Cracking Property Model.

## New Stop Criteria in the Diffusion Module (DICTRA) Console Mode

The Console Mode version of the Diffusion Module (DICTRA) now allows users to add a Stop Criteria to their simulations, which means that users can add an alternative criteria instead of the final time to terminate the simulation. For example, for a carburization simulation, you can terminate the calculation when the carbon content at a certain depth has reached the desired value.

A new REMOVE_STOP_CRITERIA command is also available to remove the stop criteria.

This feature is not available in the Graphical Mode.

## Transform 3D Size Distribution to 2D in the Precipitation Module (TC-PRISMA)

The Precipitation Module (TC-PRISMA) adds the ability to convert three-dimensional (3D) distribution to two-dimensional (2D) distribution, which allows users to compare simulations with experimental data.

Users can calculate two-dimensional:

• Size distribution
• Number density distribution
• Normalized number density distribution

This figure illustrates the two-dimensional cross section obtained from sectioning a three-dimensional dispersion of spheres, relevant to Scanning Electron and Optical micrographs taken of material with second phase precipitates.

A new example is included in the release demonstrating this new feature:

• P_16_Precipitation_Ni-Al-Cr_Stereology

## Databases and Thermophysical Properties

Thermo-Calc 2024a includes six new databases, including the introduction of our first ever database for Molten Salts applications, TCSALT1.

## TCSALT1: Molten Salts Database

TCSALT1 is a completely new thermodynamic database for molten salts. The database can be used for a variety of applications, especially for processes involved with recycling aluminum where fluxes are used. The database covers the most common fluxes and you can study the flux ability to dissolve inclusions, like oxides, removal of unwanted elements in the Al-melt and how this varies with flux composition and temperature.

The database can also be used to understand High Temperature Corrosion where molten salts can destroy the corrosion resistance.

The database includes:

• 11 Elements: Al, Ca, Cl, F, K, Mg, Na, O, Si, Sr, Zn
• 154 phases
• 57 pseudo-binary systems
• 41 pseudo-ternary systems
• 2 higher order systems: 1 Assessed Chloride (Cl) System, 1 Assessed Fluoride (F) System
• 28 mixed systems

## TCOX13: Metal Oxide Solutions Database

• Adds Electrical Conductivity for Ionic Liquid, which means that it is now possible to predict electrical conductivity and electrical resistivity for any slag composition
• One new system added: C-Ca
• Many reassessed systems*:
• Al-Fe, Fe-Si
• Al-C-Fe, Al-Fe-Mn, Al-Fe-Nb, Al-Fe-Ni, Al-Fe-P, B-Fe-Si, C-Fe-Si, Co-Fe-Si, Fe-Cr-Si, Fe-Mn-Si, Fe-Ni-Si, Fe-P-Si, and C-Fe-O
• Fe-Cr-Ni-O
• Al2O3-CaO, Al2O3-CaO-Fe-O, Al2O3-CaO-MgO, Al2O3-CaO-SiO2, Al2O3-CaO-Y2O3, Al2O3-CaO-MgO-SiO2
• Al2O3-CrOx-SiO2, Al2O3-MnO-FeO-SiO2
• Surface tension of metallic liquid was re-assessed based on the Redlich-Kister-Muggianu (R-K-M) sub-regular solution model

*Much of the work related to reassessed systems in TCOX13 is for improving the Al/Si distribution between steel and slag.

## TCHEA7: High Entropy Alloys Databases

• 7 new binary systems assessed: Mo-Sn, N-Y, Rh-Nb, Rh-Si, Rh-Ta, Rh-V, and Rh-Y
• 1 binary system reassessed: Mn-W
• 2 new ternary systems assessed: Nb-V-Zr and V-W-Zr
• Reassessed SIGMA, BCC, FCC, HCP and LIQUID phases in over 100 systems
• Surface tension re-assessed based on the Redlich-Kister-Muggianu (R-K-M) sub-regular solution model

## TCAL9: Aluminum-based Alloys Database

• 4 new elements: Ba, Sb, Ta, and W
• 38 new binary systems assessed
• 11 new ternary systems assessed
• Full Gas descriptions are added and selected by default, so the database can now be fully used with the Additive Manufacturing Module
• Mn-Ni-Zn: descriptions of BCC_B2, EPSILON are updated in order to better account for the experimental data
• Surface tension was re-assessed based on the Redlich-Kister-Muggianu (R-K-M) sub-regular solution model

## MOBAL8: Aluminum-based Alloys Mobilities Database

• 4 new elements: Ba, Sb, Ta, and W
• Assessments for FCC_A1 Phase:
• New assessments for Ag-Cu, Ag-Zn, Al-Li, Al-Ag-Cu, Al-Ag-Zn, Al-Cu-Sn
• Improved for Al-Si
• Added mobility of impurity diffusivity for Al-Ba, Al-Sb, Al-Ta, Al-W
• Assessments for Liquid Phase: mobility parameters for self- and impurity- diffusivity of the systems not previously included in MOBAL version 7 and earlier are estimated using the Modified Sutherland equation

## TCMG7: Magnesium-based Alloys Database

• Modeled molar volume of the BCC phase in the Li-Mg, Al-Fe, and Fe-Si systems
• 15 new binary systems assessed
• 5 updated binary systems
• 22 new ternary systems assessed
• 11 updated ternary systems
• A variety of work is done to improve the Long-Period Stacking-Ordered (LPSO) Phases:
• A new model for the following phases are used, where RE is rare earth elements that are included in the current database
• 5 updated binaries related to the LPSO phases
• 11 updated ternary systems related to the LPSO phases
• The surface tension was re-assessed based on the Redlich-Kister-Muggianu (R-K-M) sub-regular solution model

## Updated Databases

This release also includes updates to the copper-based alloys database, TCCU6, and to four of our demo databases, as listed on the screen.

## TCCU6.2: Copper-based Alloys Database

The copper-based alloys database was updated to version TCCU6.2. Users who have a license for TCCU6 and a valid Maintenance and Support Subscription receive this upgrade for free.

• Corrected the default setting of major components in BCC, FCC, and HCP phases
• Updated the surface tension of the Fe-Ni system

## Updated Demo Databases

Read the Release Notes for more details.

• ALDEMO
• OXDEMO
• MFEDEMO
• MALDEMO