|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||High Entropy Alloys IV
||Microstructures of Annealed and Oxidized Al8(NiCoCrFe)92, Al15(NiCoCrFe)85, and Al30(NiCoCrFe)70 High-Entropy Alloys
||Todd Butler, Mark L. Weaver
|On-Site Speaker (Planned)
High entropy alloys (HEAs) are a unique class of alloys that typically contain five or more components in nearly equal proportions. This arrangement promotes a high-entropy of mixing, which facilitates the formation of simple FCC and/or BCC solid solution phases. Their high symmetry and favorable properties make HEAs model candidates as materials for use in high-temperature structural applications. However, an adequate understanding of their oxidation behaviors is extremely limited. This work reports the 1050°C oxidation behaviors of as-cast and annealed Alx(NiCoCrFe)1-x HEAs. All of the HEAs exhibited various degrees of initial transient oxidation, followed by parabolic oxide growth. The as-cast HEAs oxidized like model Group II and Group III Ni-Cr-Al alloys, with the formation of Al2O3 and Cr2O3 scales. In contrast, the annealed/oxidized HEAs formed Al2O3, minor Cr2O3, and spinel phases. The variations in the oxidation mechanisms were attributed to the changes in phase fractions and relative phase sizes.
||Planned: A print-only volume