Metal Additive Manufacturing Conference - MAMC 2022

Advances in Additive Manufacturing by powder bed fusion technologies based on EBM (Electron Beam Melting) or SLM (Selective Laser Melting) as well as other powder based additive routes such as LMD (Laser Metal Deposition) have led to an increase of demand on spherical powders [1]. However, most applications are realized through a handful of commercially available powders. Customized alloys and new materials are needed to enlarge the field of possible applications and enhance the performance of additive manufactured parts. This presentation introduces production routes for customized Titanium-alloy powders, high-temperature alloy powders as well as refractory metal based High Entropy Powders, which represent a new class of materials for additive manufacturing, commercially unavailable until now.
For titanium alloys, the alloying elements are compacted into consumable electrodes, which are molten into an ingot via Vacuum Arc Melting (VAR) or Electron Beam Melting (EBM), depending on the alloying elements. To obtain homogeneous feedstock for the Electrode Induction Melting Inert Gas Atomization (EIGA), the ingot is remolten in an Induction Skull Melter (ISM) and gravity cast into a steel mould. This high purity feedstock is then atomized and classified under Argon atmosphere.
Through the adjustment of process parameters, the particle size distribution (PSD) can be shifted from very fine to coarse, resulting in tailored PSD for different additive manufacturing processes. [2]
A novel processing route invented by GfE allows the production of feedstock for the EIGA of alloys with very high melting points. This includes brittle, high temperature intermetallics, such as MoSiB and VSiB as well as refractory based High Entropy Alloys which cannot be processed by conventional meltmetallurgical technologies to stable EIGA electrodes. The availability of such powders represents a breakthrough, allowing results from fundamental research to be transferred into products and widening the application field of additive manufacturing.
The extension of additive manufacturing into the refractory based HEA opens the possibility to build high strength parts. The high intrinsic strength of refractory based HEA compensates the impossibility to forge additively manufactured parts to enhance the microstructure. [3]

References

[1] Sun, P., Fang, Z.Z., Zhang, Y. et al. Review of the Methods for Production of Spherical Ti and Ti Alloy Powder. JOM 69, 1853–1860 (2017). https://doi.org/10.1007/s11837-017-2513-5

[2] V. Güther, K. Ratschbacher, J. Lindemann, Manufacturing of TiAl Powders Based on Electrode Induction Gas Atomization, presentation at the Titanium Europe 2019, 13-15th May 2019, Vienna, Austria.
[3] Easo P. Gorge, Dierk Raabe, Rober O. Ritchie, High Entropy Alloys, DOE Pages, Department of Energy 2019, https://www.osti.gov/pages/biblio/1550755