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

Additive manufacturing of bulk metallic glasses (BMGs) has recently emerged as a viable method. Especially laser powder bed fusion (PBF-LB/M) was established as a promising technique to overcome the limitations in size and complexity during the fabrication of BMGs. In comparison to crystalline alloys, BMGs feature exceptional large elastic limits of about 2 % combined with high strength and hardness. Their properties profile renders them as potential candidates for disruptive material substitutions in highly stressed applications. The recently discovered sulfur-bearing TiZrCuS alloys offer high corrosion resistance and almost twice the strength of Ti6Al4V. However, their small critical casting thickness of about 1 mm is on the edge of the definition of a bulk metallic glass (1 mm or more). This effectively disqualifies conventional casting processes of this alloy as a functional production route for a broad spectrum of applications. Yet, TiZrCuS alloys feature a respectable thermal stability against crystallization in the low-temperature supercooled liquid region. This makes the system robust against crystallization under cyclic thermal exposure, as present during PBF-LB/M. However, large amounts of oxygen impurities and limited knowledge about the thermal history challenge the amorphous vitrification during PBF-LB/M. In this matter, the project aims to investigate the laser-material interaction during PBF-LB/M processing of Ti60Zr15Cu17S8. A thorough investigation of the thermal profiles and history during the transient laser-material interaction via high-speed imaging, ratio-pyrometry, and FEM simulations will be conducted in view of the resulting thermodynamic, structural, and technological properties of the manufactured samples.

• DFG Programme: Research Grants