Authors:
A. Kirchner (1), U. Gaitzsch (1), D. Dorow-Gerspach (2), B. Distl (3), M. Franke-Jurisch (1), C. Zhong (1), T. Weißgärber (1,4)
1- Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany
2- Forschungszentrum Jülich, Institut für Energie- und Klimaforschung – Plasmaphysik, Germany
3- Plansee SE, Austria
4- Institute of Materials Science, Technische Universität Dresden, Germany
Abstract:
For refractory metals additive manufacturing of near net shape parts represents an attractive opportunity, in particular for complex geometries. The combination of high melting point, thermal conductivity and brittleness represents a challenge for fusion processes. Electron beam powder bed fusion (PBF-EB) facilitates preheat temperatures above 1000°C and vacuum processing with negligible oxygen contamination. Elemental tungsten and molybdenum were PBF-EB processed to high density from spherical and non-spherical powders. The resulting microstructure is characterized by large grains elongated in build direction and texture. Accordingly, the potential for the mechanical strength of defect-free PBF-EB refractory metals corresponds to conventionally fabricated material in recrystallized condition. The cracking behavior of tungsten tiles under extreme thermal shock was analyzed. Generated test geometries include thin-walled components and lattice structures. The Mo9Si8B alloy required 1100°C preheat temperature for crack-free processing. The microstructure is fine-grained with coarsening in the lower part. The bending strength exceeds 1200 MPa at 1000°C.
DOI:
https://doi.org/10.59499/EP246281479
