Applications of Thermo-Calc to Additive Manufacturing of Metals

Additive manufacturing of metals is transforming materials design and processing in ways unimaginable even 10 years ago, offering the freedom to produce complex parts without the restraints of traditional manufacturing.

However, Additive Manufacturing is a complex process and the mechanical properties of these materials and the parameters which control their reproducibility are not yet well understood. For example, additive processes are typically associated with rapid cooling rates and large thermal gradients. This can give rise to high levels of residual stress in the final part and local inhomogeneities in alloy composition during solidification. Also, the effect of multiple thermal cycles on material properties is sometimes unknown and typically does not result in the properties of a similar cast or wrought metal.

A lot of research is now being published in this area by members of our community using Thermo-Calc and we want to share some of this work with you. Below you will find a sampling of some of the work that is being done using Thermo-Calc and our add-on modules for diffusion and precipitation to research additive manufacturing of metals.

PRESENTATION: Applications of CALPHAD based tools to additive manufacturing

This presentation shows some of the applications of Thermo-Calc to mechanical/thermal FEA modelling as well as metallurgical phenomena. It discusses materials challenges with additive manufacturing and offers three examples of how Thermo-Calc has already been applied to additive manufacturing. The presentation is similar to the one used in the webinar above, but comes in the form of downloadable slides.

PAPER: Simulation of TTT Curves for Additively Manufactured Inconel 625

This recent publication in Metallurgical and Materials Transactions A looks at the use of computational thermodynamic and kinetic software to study the microstructure evolution in Inconel 625 (IN625) which was additively manufactured. Authors: G. Lindwall, C. E. Campbell, E. A. Lass, F. Zhang, M. R. Stoudt, A. J. Allen and L. E. Levine

Abstract: The ability to use common computational thermodynamic and kinetic tools to study the microstructure evolution in Inconel 625 (IN625) manufactured using the additive manufacturing (AM) technique of laser powder-bed fusion is evaluated. Solidification simulations indicate that laser melting and re-melting during printing produce highly segregated interdendritic regions. Precipitation simulations for different degrees of segregation show that the larger the segregation, i.e., the richer the interdendritic regions are in Nb and Mo, the faster the δ-phase (Ni3Nb) precipitation. This is in accordance with the accelerated δ precipitation observed experimentally during post-build heat treatments of AM IN625 compared to wrought IN625. The δ-phase may be undesirable since it can lead to detrimental effects on the mechanical properties. The results are presented in the form of a TTT diagram and agreement between the simulated diagram and the experimental TTT diagram demonstrate how these computational tools can be used to guide and optimize post-build treatments of AM materials.

WHITE PAPER: Applying computational thermodynamics to additive manufacturing

This recent white paper published in the MRS Bulletin presents two examples of how CALPHAD-based tools have been used to address the challenges of additive manufacturing of materials. The first example discusses improving finite element modeling with CALPHAD data and the second discusses predicting optimal postbuild heat treatments. The paper was written by Adam Hope and Paul Mason, both of Thermo-Calc Software Inc.

Additional Resources for Applications to Additive Manufacturing

Thermo-Calc Software has been cited countless times in publications with regard to additive manufacturing. Learn more about applications of Thermo-Calc to this growing field on the Additive Manufacturing page on our website.