Dresden 2009 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 37: Topical Session High Temperature Materials IV
MM 37.2: Talk
Thursday, March 26, 2009, 10:45–11:00, IFW A
Microstructure Formation during Solidification in Multicomponent Gamma-Titanium Aluminide Alloys — •Michael Oehring1, Fritz Appel1, Jonathan Paul1, Renat Imayev2, Valery Imayev2, Viola Küstner3, and Uwe Lorenz1 — 1GKSS Research Centre, Institute of Materials Research, Max-Planck-Str. 1, D-21502 Geesthacht, Germany — 2Institute for Metals Superplasticity Problems, Russian Academy of Sciences, Khalturin Str. 39, 450001 Ufa, Russian Federation — 3Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, D-70569 Stuttgart, Germany
In order to exploit the potential of gamma titanium aluminide alloys as high-temperature material multicomponent alloys have to be developed that are adapted to industrial processing conditions. TiAl alloys solidifying solely via the beta-phase exhibit characteristic solidification microstructures, which often involve equiaxed instead of columnar structures, weak textures, and modest segregation. These features result from single-phase solidification and the subsequent solid-state transformations. In view of the development of improved cast alloys, the potential of the beta/alpha transformation with respect to microstructural refinement and its dependence on the addition of several alloying elements has been investigated. It was found, that particularly fine and very homogeneous microstructures can be obtained for certain alloy compositions. The microstructural refinement can be attributed to the alloying effect on the kinetics of the beta/alpha transformation and even can be achieved after slow cooling from high-temperature heat treatments.