TCFE: TCS Steels/Fe-Alloys Database Revision History

Software release version 2025a (January 2025)

Elastic Properties Added

• Elastic constants (C11, C12, C13, C33, and C44) are added for FCC_A1, BCC_A2, and HCP_A3 phases. The elastic constants description can be used to derive the elastic moduli (bulk modulus, shear modulus, and Young’s modulus) for a single-phase microstructure.
• Unary systems assessed:
  • FCC_A1, BCC_A2, HCP_A3: Al, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Ni, P, Ru, S, Si, Sn, Ta, Ti, V, W, Y, Zn, Zr
• Binary systems assessed:
  • Fe-X (X = Al, Co, Cr, Mg, Mn, Mo, Nb, Ni, Si, Ti, V, W)
  • Mo-X (X = Nb, Sn, Ta, Ti, W, Zr)
  • Nb-X (X = Sn, Ta, Ti, V, W, Zr)
  • Sn-X (X = Ta, Ti, Zr)
  • Ta-X (X = Ti, W, Zr)
  • Ti-X (X = Al, Cr, V, W, Y, Zr)
  • W-X (X = Cr, V, Zr)
  • Cr-Ni

New Systems and Phases

• 18 new ternary systems (total of 335)
• 4 new quaternary systems (total of 84)
• 30 new phases (total of 465)

Improved Solubility

• BN in liquid and solid Fe: B-N, Fe-B, Fe-B-N
• Mg in cast irons: C-Fe-Mg, C-Fe-Mg-Si
• Si in cementite phase: C-Fe-Si
• Sn in corundum phase: O-Sn, Fe-O-Sn

Improved Systems

• S systems
  • S-X (X= Ce, Co, Cr, Fe, Ni, Ru, Ti, V)
  • Fe-S-X (X=Ce, Cr, Mo, Ni, Ta, Ti, V, Zn)
  • Cr-Fe-Ni-S
• Ti systems
  • Ti-X (X=Al, Fe, Si)
  • Fe-Ti-X (X= Al, Cr, Nb, Ni, Si, V)

Improved Equilibria

Improved ɑ/σ/γ equilibria for:

• Fe-Ni-V, Cr-Ni-V, Cr-Fe-Ni-V
• Mo-V, Fe-Mo-V

Improved Descriptions

• Cubic carbides: C-Nb, C-X-Y (X-Y= Cr-Ti, Cr-V, Fe-Ti, Mo-Nb, Mo-Ti, Mo-V, Nb-Ti, Nb-V, Ti-V)
• TiN inclusions in steel melts: Cr-Fe-Ni-Ti-N
• Ni3X (X=Mo,Ti) precipitates in maraging steels: Mo-Ni, Mo-Nb-Ni, Mo-Ni-Ti, Nb-Ni-Ti

Improved Thermophysical Properties

• Thermal conductivity for cemented carbide systems improved

Software release 2023b Update 1 (September 2023)

• Thermal conductivity (THCD) and electrical resistivity (ELRS): Updated for C- and N-containing solution phases.
• Ternary system Fe-Nb-P re-assessed.

Software release 2023b (June 2023)

• The full gas description is included.
• Assessed Fe-Mn-Ti system.
• Revised Cr-Fe-Ni-Si subsystems (Cr-Fe-Si, Cr-Ni-Si) to increase the accuracy of phase equilibria involving the FCC/BCC/LIQUID phases.
• Reassessed THCD of FeTi-B2 and added THCD ELRS of BN_BK.
• Updated the Diamond molar volume and corrected wrong volume parameters.
• Updated Ca-Fe to a more recent description.
• Removed the HIGH_SIGMA phase from the Cr-Mn binary.
• Revised S-Zr and Fe-S-Zr.
• Estimated Fe-Nb-S.
• Revised the liquid in Fe-O-Y and C-Ni-Si.
• The surface tension was re-assessed based on the Redlich-Kister-Muggianu (R-K-M) sub-regular solution model.

Software release 2022a (December 2021/January 2022)

Added Tin (Sn)

• 26 Binaries Sn-X (X=Al, B, C, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Ni, O, P, Ru, S, Si, Sn, Ta, Ti, V, W, Y, Zn, Zr)
• 13 Ternaries: Fe-Sn-X (X=C, Cr, Cu, Mn, Nb, Ni, O, S, Si, W, Zn, Zr), and Al-C-Sn

New Thermophysical Properties

• Electrical resistivity is modeled for crystalline phases and liquid. The descriptions can be used for deriving electrical conductivity.
• Thermal conductivity is modeled for crystalline phases and liquid. The descriptions can be used for deriving thermal resistivity as well as thermal diffusivity (by combining with our density and heat capacity data).

Updated Zinc Corner

As well as systems related for the galvanization process:

• Remodeled and unified all gamma-brass D82 phases stable in Fe-Zn, Cu-Zn, Ni-Zn, Mn-Zn, Co-Zn with a 4SL FE3ZN7_D82.
• Added Al-Fe-Mg, Cu-Fe-Zn, Fe-Ni-Zn, Fe-Si-Zn, Fe-Mg-Si, Fe-Mg-Ni, Fe-Mn-Zn, Mg-Si-Zn

Other Updates

• Unified several phases with the same crystallography
• Corrected the low melting pseudobinary in Fe-O-Si
• Extended a ternary phosphide: FEMP_C37 (CO,CR,FE,NB,NI,TI,V,W)1(CO,CR,FE,NB,NI,TI,V,W)1P1
• Revised C-Ca and estimated C-Ca-Fe

Software release version: 2021a (December 2020/January 2021)

Thermophysical Properties

• Added surface tension of the metallic liquid.
• Updated molar volume of the liquid.

New Elements and Systems

• Added binary M-H systems where M=Al, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Ni, Ru, Si, Ta, Ti, V, W, Y, Zn, Zr.
• Liquid, FCC, BCC and HCP solutions and important hydrides are included. In addition, ternary C-Fe-H, Fe-H-Si, Cr-Fe-H, Al-Fe-H, Fe-H-Mo, Fe-H-Ni, Fe-H-V, Fe-H-W, Al-H-Ti, H-Ni-Ti, H-Ti-Zr systems and quaternary C-Fe-Mn-H, Cr-Fe-H-Ni systems were verified against the experimental data.
• Al-Fe-Nb, Fe-Nb-Ni, Co-Fe-Nb, Al-Cr-Nb
• Al-Fe-Zr, Cr-Fe-Zr, Cu-Fe-Zr
• Ca-P, Ca-Ti, Ca-V, Ca-W
• Ce-Nb, Ce-Ta, Ce-Ti, Ce-W
• Ca-N, N-Y, Ce-N
• Nb-Zn, Ta-Zn, W-Zn, Fe-Nb-Zn
• P-V, Fe-P-V
• S-Ta

Updated Systems and Phases

• Fe-N and C-Fe-N are updated to a more recent modeling work including the non-stoichiometric composition of Fe₄N nitride.
• Fe-Si and C-Fe-Si are updated to avoid a high temperature miscibility gap in the liquid.
• Cr-Si, Cr-Fe-Si, and C-Cr-Si are updated to a more recent modeling work.
• FeNbP, FeTiP, NbCrP, NbNiP, CrNiP are modeled as FEMP_C23 phase.
• Co-Nb, Cr-Nb, and Cr-Nb-Ni are updated to separate C15 and C14 laves phases.
• Fe-Y is updated to a more recent modeling work.
• Fe-Zr and Fe-Si-Zr are updated to a more recent modeling work.
• Fe-Nb is updated with an updated formation energy of MU_D85 phase.
• Nb-N is updated to a more recent modeling work.
• Ni-S is updated to assess the solubility of S in FCC nickel.

A simulanteous release as part of software release version: 2021a (December 2020/January 2021)

• For users who have TCFE8 and TCFE9 and also use the Steel Model Library, there is an update to correct the volume of liquid Zn.

Software release version: 2020b (June 2020)

There was a simultaneous update to both TCFE9 and TCFE10 that is bundled with the 2020b software release and needed for the Steel Model Library Martensite Temperature Model.

• Revised parameters of BCC_A2 phase in Fe-Mn-N system to avoid the appearance of a high N composition set at low temperatures.
• Removed a previously added ad-hoc modification to the lattice stability of BCC_A2 Nickel at temperatures below 450K.

Software release version: 2020b (June 2020)

There was a simultaneous update to both TCFE9 and TCFE10 that is bundled with the 2020b software release and needed for the Steel Model Library Martensite Temperature Model.

• Removed a previously added ad-hoc modification to the lattice stability of BCC_A2 Nickel at temperatures below 450K.

Software release version: 2020a (January 2020)

The TCFE10 database is significantly improved compared to TCFE9. Below is a summary of the major updates. Read more detail on the TCFE history section on our website.

• 53 new binary and 13 new ternary systems are included.
• More than 15 binary and 14 ternary systems , and many quaternary, are either completely updated or partially modified to improve the database's robustness and predictability.
• Addition of Ru and 19 Ru-X binary systems (X=Al, B, C, Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Ni, S, Si, Ta, Ti, V, Zn). In addition, the Cr-Fe-Ru is assessed at the Fe corner.
• Better predictive capacity for nitrogen alloyed duplex stainless steels: The systems relevant for nitrogen alloyed duplex stainless steels were systematically reviewed and revised as necessary.
  • The database predictivity is improved in these critical areas: Equilibria at liquidus - solidus; equilibria of matrix phases (α+γ) at high temperature; and equilibria of secondary phases at intermediate temperature.
• TCFE10 contains 31 new phases among which the so called η- silicide is named as ETA_M5SIN; and τ1-silicide (Fe2.5Ni1.5Si) and π-silicide (Cr1.5Ni2.5Si) are modeled as M4SI1_G3.
• The viscosity of metallic liquid alloys is modeled in TCFE10.
• Split description of ordered phases: The ordered phases BCC_B2 and FCC_L12 are described based on the order/disorder partitioning model as described by Lukas et al. [2007].

Software release version: 2019b (June 2019)

The changes include:

• Revision of C-Fe-S system.
• Revision of Cr-Fe-Nb and Fe-Nb-Si system and the addition of 15 new silicide phases.
• Revision of the Laves phase description in Fe-Nb-W and Cr-Mo-Nb systems.
• Updates to the molar volumes of Liquid Mn, CEMENTITE, Fe-Si-B ternary phases, MNS, and several sulfides.
• Correction of the magnetic properties of CBCC_A12 phase.
• Removing the pressure dependent parameters from Fe for compatibility with GES6.

Software release version: 2017a (March 2017)

Below is a summary of the major updates. Read more detail on the TCFE history section on our website

The database is developed and validated for simulation of the solidification process, the relative stability of matrix phases (austenite and ferrite), precipitation of secondary phases such as sulfides, borides, oxides, phosphides, carbides, nitrides, carbonitrides, and also intermetallic phases such as the sigma and laves phases.

The TCFE9 database is significantly improved compared to the previous TCFE8 version, with 32 new binary and 35 new ternary systems added to the database. In addition, more than 50 binary and 39 ternary, and many quaternary, systems are either completely updated or partially modified to improve the robustness and predictability of the database.

Software release version 2016b (November 2016)

• A bug fix that previously resulted in a faulty estimation of molar volume of borides.
• The change of description of Fe-B and Fe-Ti-B systems due to incompatibility

Software release version: 2015a (June 2015)

In order to increase the predictive capability of the database, several significant re-assessments have been performed by Thermo‑Calc Software AB which are incorporated in the new release.

The elements Zn and Y and relevant phases associated with these elements have been added in the new TCFE8.

The element Zn has been added mainly for the purpose of galvanization process with the focus on the Zn corner of Al-Cr-Fe-Zn system for, but several other binaries and ternaries are also included. The element Y has been added mainly for the purpose of oxide dispersion strengthened (ODS) steels and the Al-Cr-Cu-Fe-Mn-Ni-O-Si-Y-Zr has been included which contains many assessed oxygen containing binary and ternary systems.

The description of Cu containing systems are improved with addition of Co-Cu, Co-Cu-Fe and Cu-Fe-Si data.

The FE2SITI_L21 phase has been added in the database which is important for the Fe-Si-Ti precipitation hardening steels.

The LIQUID, MU_PHASE, LAVES_PHASE_C14, SIGMA and L12_FCC phases have been improved due to the modifications for the LIQUID in the Mn-O-S, Mo-Si, C-Fe-Si and C-Fe-O systems, MU_PHASE in the Co-Nb and Co-Ta systems, LAVES_PHASE_C14 in Co-Mo and Cu-Fe systems, SIGMA phase in the Co-Cr, Al-Nb, Mn-Ta, Mo-V, Nb-V, Ta-Ti and Ta-V systems, and L12_FCC in Co-V system.

The description of C-Co-Cr system has also been added for cemented carbide applications.

All necessary volume data (including molar volume and thermal expansion) has been updated for all phases in this new release. However, the molar volume data incorporated has no pressure dependence.

Some of the major improvements to the TCFE8 database include improved/added thermodynamic descriptions for several binary, ternary and quaternary systems.

TCFE7 released in 2012.

In order to increase the predictive capability of the database, several significant re-assessments have been performed by Thermo‑Calc Software AB which are incorporated in the new release. The elements Ta and Zr and relevant phases associated with these elements have been added. Three more B containing phases and two more Mn nitride phases have been also implemented into the new TCFE7 database. All oxide phases for the Fe-Al-Ca-Cr-Mg-Mn-Ni-Si-O system have been updated or added, which includes the addition of many new oxide phases.Within the latter system all lower-order sub-systems have been evaluated.

In version 4 (TCFE4), all necessary volume data (including molar volume and thermal expansion) for various alloy phases were incorporated; such volume data has been updated for all phases in this new release. However, the molar volume data incorporated has no pressure dependence.

Some of the major improvements to the TCFE7 database include improved/added thermodynamic descriptions for the following binary, ternary and quaternary systems (with many sub-systems also re-assessed).

TCFE6 released in 2008.

In order to increase the predictive capability of the database, several significant re- assessments have been performed by Thermo‑Calc Software AB and incorporated in the new release. The element Ca has been added and the alloying ranges for the elements C, Co, Cu, N, Ti and V have been extended. In version 4 (TCFE4), all necessary volume data (including molar volume and thermal expansion) for various alloy phases were incorporated; such volume data has been updated for all phases in this new release. However, the molar volume data incorporated has no pressure dependence.

Some of the major improvements to the TCFE6 database include improved thermodynamic descriptions for the following ternary and quaternary systems (with many sub-systems also re-assessed).

TCFE5 released in 2007.

This release builds on to the previous version of the database, i.e. TCFE4, and additionally includes complete reassessments of several binary and ternary systems performed under a three year collaborative program within the framework of the CCT-Applied project for stainless steels. CCT (Centre of Computational Thermodynamics) is a collaborative effort between the Royal Institute of Technology (Stockholm, Sweden), Kimab and Swedish industries.

Some of the major improvements to the TCFE5 database include improved thermodynamic descriptions for the following ternary and quaternary systems:

• C-Cr-Si
• Cr-Ni-N
• Fe-Cr-Cu
• Fe-Cr-Si
• Fe-Ni-N
• Fe-Ni-Si
• Fe-Cr-Mo-C
• Fe-Cr-C-N
• Fe-Cr-Mn-N
• Fe-Cr-Mo-N
• Fe-Cr-Ni-N
• Fe-Cr-Si-N
• Fe-Cr-Ni-Al
• Nb-V-C-N

TCFE4 released in 2005-6.

This release builds on the previous version of the database, i.e. TCFE3, and additionally includes a complete assessment of molar volume data for all phases typically present in steels.

The benefit from having molar volume data included in the database is the possibility to calculate and plot directly within Thermo‑Calc:

• Volume fraction of phases.
• Volume for a phase or for the whole system.
• Density for a phase or for the whole system.
• Lattice parameters (for phases having cubic structures).
• Relative length change and thermal expansion coefficients.

TCFE3 is the successor of the well-known TCFE2 (i.e., TCFE-2000 or TCFE2K) thermodynamic database for steels and Fe-alloys. A number of improvements have been made in order to increase the predictive capability of the TCFE3 database.

Some of the major improvements are:

• Improved data for the important -phase in stainless steels.
• Addition of data for the binary Nb-Ni system.
• Improved data for the ternary Fe-Cr-Mo system.
• Improved data for the ternary Cr-Mo-Ni system.
• Improved data for the fcc Ti(C,N) carbonitride.

• TCFE 2.0 was released in 1999/2000 and was also called TCFE2000.
• TCFE1.5 was released in 1996 and also called FEDAT.