Sulfur bearing Ti-based bulk metallic glasses for the Laser Powder Bed Fusion of metals

• Applicants: Professor Dr. Ralf Busch; Dr.-Ing. Stefan Kleszczynski
• Subject Area: Materials in Sintering Processes and Generative Manufacturing Processes ; Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 503259970

Laser Powder Bed Fusion of Metals (PBF-LB/M) has established itself as a promising technology for overcoming the size and complexity limitations of Bulk Metallic Glasses (BMGs). In comparison to crystalline alloys, BMGs exhibit an exceptionally high yield strength of approximately 2% in combination with high strength and hardness. Their property profile makes them potential candidates for substituting materials in high-stress applications. The recently discovered sulfur-containing TiZrCuS alloys offer high corrosion resistance and nearly double the strength of Ti6Al4V. However, their low critical casting thickness of approximately 1 mm lies at the edge of the definition of a massive metallic glass (1 mm or more). This means that conventional casting methods for this alloy are not suitable. TiZrCuS alloys exhibit remarkable thermal stability against crystallization at low temperatures, particularly in the undercooled liquid region. This makes the system robust against crystallization under cyclic thermal loading, which occurs during the PBF-LB/M process. High oxygen contamination and limited knowledge about the thermal material history, however, pose a challenge for the amorphous solidification during the PBF-LB/M process. Based on the findings of the first funding phase, the present project aims to deepen the understanding of the influences of powder material synthesis and alloy composition. This includes, in particular, the material-induced formation of oxygen contamination, glass-forming ability, mechanical stability against process-induced defects, and the resulting processability in the PBF-LB/M process. Further experimental and simulation studies of the thermally transient laser-material interaction will be conducted using high-speed imaging, quotient pyrometry, and FEM simulations. The results of these studies will be analyzed in terms of the resulting thermodynamic, structural, and technological properties of the produced samples. The resulting physical property profile can ultimately demonstrate the technological relevance of glass-forming, PBF-LB/M-processed TiZrCuS-BMGs.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Jan Wegner