About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
|
Materials Design Approaches and Experiences V
|
Presentation Title |
Oxidation Resistant Refractory Metal High Entropy Alloys for Ultrahigh Temperature Structural Applications |
Author(s) |
Bronislava Gorr, Steven Schellert, Franz Mueller, Stephan Laube, Hans Chen, Alexander Kauffmann, Hans-Juergen Christ, Martin C. Heilmaier |
On-Site Speaker (Planned) |
Martin C. Heilmaier |
Abstract Scope |
We report on our development status of refractory metal based high entropy alloys for ultrahigh temperature structural engineering materials. Different alloys within the system Nb-Ta-Mo-Cr-Ti-Al were synthesized by arc melting. Applying suitable homogenization treatment leads to the presence of a single phase with B2 order at low temperatures T which is in some alloys responsible for a brittle-to-ductile transition occurring between 600 and 1000 °C. Solid solution hardening below BDTT is predicted using the atomic size difference as main relevant parameter. Elevated temperature behavior was investigated utilizing compression creep (T = 900…1100 °C) and continuous and cyclic oxidation tests in laboratory air in an even wider range of T between 500 and 1500 °C. Promising properties were noted, in particular TaMoCrTiAl forms a protective CrTaO<sub>4</sub> scale which exhibits very low growth rates and is well adherent. Thus, it is responsible for low weight gains and the absence of catastrophic oxidation. |
Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |