Coarsening and growth of meta-stable gamma''-precipitates in Nickel-base Superalloys

• Applicant: Professor Dr.-Ing. Uwe Glatzel, since 10/2019
• Subject Area: Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials ; Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 387117768

• Final Report Year: 2021

Final Report Abstract

The aim of the project was to investigate chemo-mechanical effects in the growth and ripening of meta-stable γ-precipitates in niobium containing nickel-based superalloys. Niobium containing nickel-base superalloys, such as Inconel 718, belong to an important class of applied materials, which show a strong coupling of thermo-chemical and thermo-mechanical states. The importance of Inconel 718 can be recognized by the fact that - to the best of the authors knowledge - it is the only material to which a whole conference-series is dedicated: The conference "Superalloy 718 and derivatives" takes place in a 4-year cycle beginning in 1986 in Pittsbugh, USA! The precipitation microstructures were comparatively studied by means of novel computer simulations using the so-called phase-field approach as well as tailor-made, metallurgical experiments. In accordance with the objectives of the priority program, the development of physically based material models with complete coupling between chemistry and mechanics was also the subject of the project. Upon the successful completion of the project the following scientific advances have been made: • The applicability of the phase-field method in the context of materials science simulations has been significantly improved by the formulation of more efficent models as well as the development of quantitative simulation configurations. • The overall understanding the of precipitation of meta-stable γ in nickel-based alloys is substantially grown. With a realistic γ -volume fraction of 12%, chemoelastic interactions between the precipitates play a decisive role in the formation of the microstructure, both in terms of the precipitate arrangement as well as the shapes of the precipitate.

Publications

• Phase field modeling of solidification in multi-component alloys with a case study on the Inconel 718 alloy. J. Mater. Res. 32, 4605–4615 (2017)
  M. Fleck, F. Querfurth, and U. Glatzel
  
• Phase-field modeling of precipitation growth and ripening during industrial heat treatments in ni-base superalloys. Metall. Mater. Trans. A 49, 4146–4157 (2018)
  M. Fleck, F. Schleifer, M. Holzinger, and U. Glatzel
  
• Elastically induced pattern formation in the initial and frustrated growth regime of bainitic subunits. AIMS Mater. Sci. 6, 52–62 (2019)
  N. Ta, K. Wang, X. Yin, M. Fleck, and C. Hüter
  
• Phase-field modeling of γ -precipitate shapes in nickel-base superalloys and their classification by moment invariants. Euro. Phys. J B 92, 208 (2019)
  M. Holzinger, F. Schleifer, U. Glatzel, and M. Fleck
  
• On the interaction between γ precipitates and the dislocation microstructures in nb containing single crystal nickel-base alloys. Mater. Character. 165, 110389 (2020)
  Y.-Y. Lin, F. Schleifer, M. Fleck, and U. Glatzel
  
• Phase-field modeling of a γ/γ microstructure in nickel-base superalloys with high γ volume fraction. Intermetallics 120, 106745 (2020)
  F. Schleifer, M. Holzinger, Y.-Y. Lin, U. Glatzel, and M. Fleck
  
• Phase-field modeling of γ and γ precipitate size evolution during heat treatment of Ni-base superalloys, chap. 49. Superalloys 2020 – TMS Series (Springer, 2020)
  F. Schleifer, M. Fleck, M. Holzinger, Y.-Y. Lin, and U. Glatzel
  
• Quantitative shape-classification of misfitting precipitates during cubic to tetragonal transformations: Phase-field simulations and experiments. Materials 14, 1373 (2021)
  Y.-Y. Lin, F. Schleifer, M. Holzinger, N. Ta, B. Skrotzki, R. Darvishi Kamachali, U. Glatzel, and M. Fleck
  
• Quantification of Solid Solution Strengthening and Internal Stresses through Creep Testing of Ni-Containing Single Crystals at 980 °C. Metals 11 (2021)
  U. Glatzel, F. Schleifer, C. Gadelmeier, F. Krieg, M. Müller, M. Mosbacher, and R. Völkl
  
• Simulation of the θ precipitation process with interfacial anisotropy effects in al-cu alloys. Materials 14 (2021)
  N. Ta, M. U. Bilal, I. Häusler, A. Saxena, Y.-Y. Lin, F. Schleifer, M. Fleck, U. Glatzel, B. Skrotzki, and R. Darvishi Kamachali