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@PHDTHESIS{Seliga:40795,
      author       = {Seliga, Tomá$\check{s}$},
      title        = {{U}ntersuchungen der {S}trukturstabilität von
                      {N}i-({F}e)-{B}asislegierungen für {R}otorwellen in
                      {D}ampfturbinen mit {A}rbeitstemperaturen über 700°{C}},
      volume       = {38},
      school       = {RWTH Aachen},
      type         = {Dr. (FH)},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {PreJuSER-40795},
      isbn         = {3-89336-392-0},
      series       = {Schriften des Forschungszentrums Jülich. Reihe
                      Energietechnik/Energy Technology},
      pages        = {105 S.},
      year         = {2005},
      note         = {Record converted from VDB: 12.11.2012; RWTH Aachen, Diss.,
                      2005},
      abstract     = {There is a continuous trend to improve the efficiency of
                      modern power plants with steam turbine require operating
                      steam temperature from 700 to 720°C. For substantial parts
                      like turbine rotors and discs this means increased
                      requirements on the high temperature resistance, which can
                      not longer be fulfilled by the presently used steel. As new
                      materials for the components, which are thermo-mechanically
                      loaded, only Ni-based superalloys are suitable for their
                      fabrication, structure stability and thermo-mechanical
                      characteristics. With view on creep and creep crack growth
                      resistance as suitable candidates in the context a DFG
                      research project wrought Ni-based superalloy Waspaloy and
                      Ni-Fe-based alloy Inconel 706 were selected, which exhibited
                      different hardening mechanisms. Waspaloy is a
                      $\gamma$’-hardened material with small portion of carbides
                      on the grain boundaries. Inconel 706 is a particle hardened
                      alloy with a very complex microstructure, it consists of
                      $\gamma$’, $\gamma$’’-particle, $\eta$-phase und
                      carbides. Concerning to their castability, forgeability,
                      creep and creep crack growth and microstructural stability
                      these candidate materials have been investigated and
                      modelled. The knowledge about their long time stability of
                      the microstructure, castability, forgeability and mechanical
                      properties leads to the two new modification (Waspaloy
                      $\rightarrow$ DT750 and Inconel 706 $\rightarrow$ DT706).
                      The modification of the Waspaloy to DT 750 served better
                      castability (elimination of the Freckle formation). An
                      improvement of the long-term stability of the microstructure
                      was not necessary, by a changed heat treatment was reached a
                      homogeneous, monomodale $\gamma$’-particle distribution.
                      The modification of Inconel 706 to DT 706 served to
                      stabilize the $\gamma$’-phase and to reduce of the
                      $\gamma$’’ phase without suppressing the cellular
                      $\eta$-phase colonies on the grain boundaries. This work
                      presents the test results for the structural long-term
                      stability of the mentioned materials and their
                      modifications. In this paper influences of heat treatments
                      and thermal exposure on the microstructure and consequences
                      for the mechanical behaviour will be discussed.},
      cin          = {IWV-2},
      ddc          = {620},
      cid          = {I:(DE-Juel1)VDB2},
      pnm          = {Werkstoffsysteme für Kraftwerke},
      pid          = {G:(DE-Juel1)FUEK248},
      typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/40795},
}