Deformation mechanism maps and and strength-controlling mechanisms for predicting the mechanical properties of polycrystalline superalloys (T11*)

• Subject Area: Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 190389738

In this transfer project, the FAU and MTU Aero Engines AG are collaborating to lay the foundations for physically based modeling of the static properties of the polycrystalline Ni-based superalloy Udimet720Li. The methods and findings generated in the SFB on single crystal alloys will be used and transferred to an application required by the industrial partner. In detail, the aim is to comprehensively characterize the dominant deformation mechanisms in Udimet720Li in certain stress, temperature and deformation rate regimes and, on the basis of this, to derive physically based material models for predicting the mechanical properties. The forging alloy Udimet720Li is of particular interest here, as this alloy is one of the highest-strength alloys that can still be processed via the cast & wrought route, and its outstanding high-temperature capacity is making it increasingly important for future, more efficient engines. The static properties of a forging alloy are determined by its microstructure and the prevailing deformation mechanisms. Physically based modeling of these properties therefore requires knowledge of the prevailing deformation mechanisms as a function of temperature and stress, and how they are influenced by microstructural conditions such as grain size, grain orientation and degree of recrystallization, as well as the local chemical composition. Due to the complexity and diversity of the deformation mechanisms, their comprehensive characterization and quantification is novel. The transfer project determines these correlations by means of various microscopic characterization and tomography methods tested in the SFB, creates so-called deformation mechanism maps in the stress-temperature-deformation rate space and uses the data obtained to validate and extend existing lifetime models.

• DFG Programme: CRC/Transregios (Transfer Project)
• Subproject of: TRR 103: From Atoms to Turbine Blades - A Scientific Approach for Developing the Next Generation of Single Crystal Superalloys
• Applicant Institution: Ruhr-Universität Bochum
• Business and Industry: MTU Aero Engines AG
• Project Head: Dr.-Ing. Steffen Neumeier