Particle modification of niobium MASC alloys by processing under semi-levitation in a cold wall induction crucible

• Applicants: Professor Dr.-Ing. Egbert Baake; Professor Dr.-Ing. Hans Jürgen Maier
• Subject Area: Metallurgical, Thermal and Thermomechanical Treatment of Materials ; Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 457358364

Alloy systems based on niobium-silicon represent an attractive alternative to industrially processed nickel-based superalloys. Due to their promising properties, niobium-MASC systems (metal and silicide composites) are candidates for use as high-temperature components and open up a wide field of research. The potential of particle modification of niobium-MASC systems was investigated for the first time during the first part of this research project. The results show that the addition of suitable particle systems can influence the formed phases and their morphology and size. This can be used specifically to improve the mechanical properties. Based on these results, particle modification in combination with directional solidification will be investigated within the second part of the research project. In addition to improving the high-temperature properties by eliminating the grain boundaries that run transverse to the direction of loading, the morphology and size of the individual phase components are also to be adjusted. By this, the positive effects already achieved can be retained. The effects of a combination of different particle types that have proven to be promising will be fundamentally investigated as part of the research project. Once a suitable combination of particles has been selected, processing is carried out under semi-levitation in a cold-wall induction crucible with the aid of the process parameters determined by numerical simulation. During directional solidification, the electromagnetic forces prevent the particles from concentrating at the solidification front, resulting in a uniform particle distribution in the solidified structure. The particle-modified, directionally solidified alloys are analyzed with regard to the microstructure and phase formation as a function of the process parameters and the underlying mechanisms of action are recorded. Additional mechanical tests provide information about the properties at room and high temperature and are linked to the microstructural change. Particle reinforcement with directional solidification and an efficient production route by means of processing in the cold-wall induction crucible will open up new perspectives for the alloy system and expand the economic field of application.

• DFG Programme: Research Grants