|About this Abstract
||1st World Congress on High Entropy Alloys (HEA 2019)
||High Entropy Alloys 2019
||Oxidation Resistant Refractory High Entropy Alloys for High Temperature Structural Application
||Bronislava Gorr, Franz Mueller, Steven Schellert, Hans Juergen Christ, Hans Chen, Alexander Kauffmann, Martin Heilmaier
|On-Site Speaker (Planned)
Many High Entropy Alloys (HEAs) exhibit unusual or outstanding properties compared to those of conventional materials. In this contribution, a refractory HEA system which shows exceptionally high oxidation resistance at high temperatures is presented. The oxidation behavior of several alloys within the alloy system Ta-Mo-Cr-Ti-Al was studied in a wide temperature range from 500°C to 1500°C. Even at very high temperatures above 1300°C, the oxidation kinetics of the equiatomic alloy 20Ta-20Mo-20Cr-20Ti-20Al follows the parabolic rate law yielding very moderate oxidation rates. The oxidation resistance relies mostly on the formation of the protective oxide CrTaO4 that forms at the interface oxide/substrate as a result of the inward oxygen diffusion. During initial oxidation stage, TiO2 and Al2O3, which were identified as transient corrosion products, protect the alloy from severe corrosion attacks. The underlying oxidation mechanisms as well as general perspectives of the refractory HEAs in terms of oxidation resistance are discussed.