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 refractory metals offer an attractive alternative to commercially available nickel-base superalloys. Niobium-MASC systems (Metal And Silicide Composites) are of interest for application in high-temperature components. Due to their promising properties, niobium silicide systems are widely researched and are now in their fourth development generation.Within the scope of this research project, the potential of a particle modification of existing Nb-MASC systems will be investigated for the first time. In addition to a direct strengthening by dispersion hardening or precipitations, the morphology and size of the individual phase components are to be adjusted by the particles to improve the alloys' properties. Thus, the particle modification will offer new perspectives for the niobium MASC alloys. Increased strength and a more efficient production route using cold wall induction crucible processing will expand the spectrum of commercial applications and improve the specific material properties.The first task will be to identify a suitable particle system. The mechanisms by which the Nb-MASC alloy system is affected by the particles, the influence of a subsequent heat treatment, and its influence on the stability of the particles will be investigated. After selecting a suitable alloy and particle system, the material is processed under semi-levitation in a cold wall crucible and the process inherent stirring effect will be exploited to ensure a homogeneous particle distribution. The almost contactless melting of the niobium-based alloy in the cold wall induction crucible results in an extremely high purity and offers a high process stability. Finally, the modified Nb-MASC alloy will be mechanically tested and the suitability for high temperature application will be assessed based on the mechanical properties in the relevant temperature range. The mechanisms between adjusted microstructure and achieved (hot) strength will be analysed and described.

• DFG Programme: Research Grants