Institute I: General Materials Properties
Hardness measurements of fully lamellar Titanium Aluminides, using the Nanoindenting ‑ Atomic Force Microscope Technique
Influence of the alloying elements Niobium, Tantalum and Zirconium on the creep properties of fully lamellar Titanium Aluminides
Titanium aluminides represent a relatively new class of materials and were taken into consideration as a construction material during the last decades. Their high potential as substitutional material for the established nickel-base superalloys is related to their considerably lower density. This difference in the density results in enormous weight savings, which is of particular interest for components that are subjected to stress from centrifugal force, such as turbine blades or turbochargers.
Fully lamellar titanium aluminides exhibit a microstructure of alternating lamellae with semicoherent interfaces of the two intermetallic phases γ (TiAl) and α2 (Ti3Al) and show the best creep properties compared to other microstructures in titanium aluminides.
Through the addition of alloying elements, the creep properties can be significantly improved, in comparison to a binary alloy. In this study, the influence of the alloying elements Niobium, Tantalum and Zirconium on the solid solution hardening, the lattice misfit, the c/a‑ratio of the γ‑phase, the diffusion and the microstructural stability are investigated. The obtained results will be used for the development of Titanium Aluminides with enhanced creep strength.