Mikrostruktur und Verformungsmechanismen in einkristallinen Nickelbasis-Superlegierungen nach Zug- und Torsionsbelastung bei 1000 Grad Celsius
Mikrostruktur und Verformungsmechanismen in einkristallinen Nickelbasis-Superlegierungen nach Zug- und Torsionsbelastung bei 1000 Grad Celsius
Modern stationary gas turbines are increasingly used for the power generation. The rotor blades of the first stage consist of single crystalline nickel-base alloys. They contain a high volume fraction of the hardening $\gamma$' phase. In spite of the internal cooling of the blades the material...
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Personal Name(s): | Steller, I. (Corresponding author) |
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Schubert, F. / Nickel, Hubertus | |
Contributing Institute: |
Publikationen vor 2000; PRE-2000; Retrocat |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
1996
|
Physical Description: |
IV, 148 p. |
Document Type: |
Report Book |
Research Program: |
ohne Topic |
Series Title: |
Berichte des Forschungszentrums Jülich
3245 |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Modern stationary gas turbines are increasingly used for the power generation. The rotor blades of the first stage consist of single crystalline nickel-base alloys. They contain a high volume fraction of the hardening $\gamma$' phase. In spite of the internal cooling of the blades the material temperatures reach about 1000°C. The influence of the service load leads to a change of the two-phased microstructure of these alloys. The aim of this work is the investigation of the microstructural processes taking place at complex load conditions. Therefore, a series of creep, tensile and torsional experiments with different superalloys were performed. The test temperature was 1000°C, the intensity of the load was similar to the service conditions of a turbine blade. A series of experiments with <001>-oriented sampies were used to examine different parameters ($\gamma$' volume fraction, $\gamma$' morphology, mismatch) concerning their influence on the creep behaviour. Further experiments with <101>- and <111>-oriented samples had the objective of determining the stability of the microstructure during different load conditions. Scanning electron microscopical investigations showed, that the oriented coalescence of the $\gamma$'-precipitate particles appears also under torsional load. The determination of the interactions between the dislocations and the precipitates was performed by means oftransmission electron microscopy. The result of the analysis of the activated slip systems was that only one of the two theoretically assumed mechanisms was responsible. Based on these observations a model of the microstructural evolution was developed for different crystallographic orientations. The model consists of different cooperating mechanisms, which mainly depend on the deformation velo city. The orientation dependence of the creep behaviour could be proven. Further investigations lead to an evaluation of the phase formation and recrystallization phenomena in superalloys and their oxidation behaviour. |