Projekt

A directionally solidified nickel-base superalloy for the use as turbine blade material in industrial gas turbines is developed in co-operation with partners from industry (Siemens Power Generation, DONCASTERS Precision Castings - Bochum) and scientific institutes (University of Applied Sciences Osnabrück, IfW Darmstadt, Institute WTM of University Erlangen-Nürnberg). The influence of different refractory elements like tungsten, molybdenum and especially rhenium (as particularly important examples) on the different microstructural and mechanical properties of more than 30 experimental alloys with varying chemical compositions is investigated. In this regard, especially the effects of rhenium additions on the lattice mismatch and microstructure of the alloys are investigated with high resolution X-ray diffraction and transmission and scanning electron microscopy. The different alloys are investigated in the standard heat-treated state and after long term high-temperature annealing and creep deformation in compression to achieve a deeper understanding of the influences of the different alloying elements on the mechanical properties at high temperatures. Furthermore, the precipitation of so called topologically close-packed phases (TCP) and their effects on the mechanical properties are of interest in these highly alloyed materials and have been investigated and simulated with different methods for some selected alloy variants. The project was completed successfully, and a patent application for one alloy composition which showed improved overall properties compared with existing alloys was filed.