Undercooling of superalloys and casting quality of single-crystal turbine blades

• Applicant: Professor Dr.-Ing. Andreas Bührig-Polaczek
• Subject Area: Metallurgical, Thermal and Thermomechanical Treatment of Materials
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 229777280

Previous superalloy development focussed on the improvement of high temperature properties without considering the castability of single-crystal components. In this submitted research grant the undercoolability of today's superalloys will be systematically researched in order to investigate their susceptibility to casting defects. The focus of this project is on the latest 4th generation superalloys. These will be examined in order to find out about mechanisms contributing to the achievement of a sufficient undercooling to make the manufacturing of single-crystal components and complex geometries like turbine blades possible.Here, fundamental scientific questions such as the nucleation and dendrite growth of complex multicomponent alloys under problematic conditions will be at the forefront of our research. The dependency of the undercooling on the composition shall be determined by statistic regression, systematic alloying addition and correspondent microstructure characterisation. The impact of critical alloying elements shall be investigated in depth.The results of this study will form an important contribution to the development of superalloys and will help to achieve an optimal combination of the desired mechanical properties with the required castability for the manufacturing of single-crystal components.

• DFG Programme: Research Grants