Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 31: Topical Session High Temperature Materials II
MM 31.3: Vortrag
Mittwoch, 25. März 2009, 15:45–16:00, IFW A
Temperature dependence of the lattice misfit of rhenium and ruthenium containing nickel-base superalloys — •Steffen Neumeier1, Sigrid Schwub1, Florian Pyczak2, and Mathias Göken1 — 1Department of Materials Science & Engineering, Institute I, University Erlangen-Nürnberg, 91058 Erlangen, Germany — 2Institute for Materials Research, GKSS Research Centre Geesthacht, Geesthacht 21502, Germany
To improve the temperature capability of nickel-base superalloys an increasing amount of refractory alloying elements, especially rhenium (Re) and ruthenium (Ru) has been added during the last decades. These 4th generation nickel-base superalloys possess an increased lattice misfit between the γ- and γ′-phase. Since the lattice misfit varies with temperature and its magnitude is decisive for the evolution of the γ/γ′-microstructure during creep deformation the lattice misfit of several experimental alloys with systematically varied contents of Re and Ru was investigated at temperatures up to 1100 ∘C using high-resolution X-ray diffraction. It was found that the lattice misfit depend strongly on the chemical composition of the alloys and the partitioning behavior of the alloying elements. Measurements of the hardness of both phases by nanoindentation in an atomic force microscope correspond well with the partitioning behavior. Also the temperature dependence of the lattice misfit is modified by Re and Ru. The change of the lattice misfit with temperature is significantly smaller in all Re-containing alloys compared to Re-free alloys and even less pronounced in Ru-containing alloys.