Determination and influence of short-range ordering on solid solution strengthening in Ni-base alloys

• Applicant: Professor Dr.-Ing. Uwe Glatzel
• Subject Area: Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545515335

Ni-based superalloys are used in high-pressure blades of aero engines where creep resistance is one of the life-limiting factors. The creep properties of such Ni-based superalloys can be improved by increasing the amount of refractory elements such as Re, W, and Mo. These elements have a solid solution strengthening effect, with Re being known to have the strongest impact. To date, this "Re-effect" on the dislocation mobility, and thus the creep properties, is not fully understood, and relevant parameters must be identified and characterized. In particular, the question is to what extent changes in the stacking fault energy or the short-range order influence the high-temperature creep properties. The proposed project addresses this issue, focusing on the high-temperature creep properties. In the project, single-phase Ni-based alloys with a similar composition to the matrix phase in superalloys, containing different amounts of refractory solutes and particularly Re, will be manufactured. The alloys will then be cast into single crystals from which specimens for creep testing in the temperature range of 850 °C to 1050 °C will be prepared. In addition, Transmission Electron Microscopy (TEM) will be carried out. This includes high-temperature TEM deformation tests and a detailed characterization of the local chemical composition, the microstructure, and the deformation mechanisms. Based on this study using single-phase, single crystal Ni-alloys, the “Re-effect” in the matrix phase of superalloys can be fundamentally understood.

• DFG Programme: Research Grants
• International Connection: France
• Partner Organisation: Agence Nationale de la Recherche / The French National Research Agency
• Cooperation Partner: Professorin Dr. Florence Pettinari-Sturmel