Speaker
Description
The single-phase microstructure of high entropy alloys (HEA) makes them perfectly suited to address fundamental scientific issues related to concentrated solid solutions. For this purpose, fcc and bcc HEA CrMnFeCoNi, TiZrNbHfTa and TiZrNbHfV were characterized as single-crystal (SX) and polycrystal regarding tensile and creep properties at higher temperatures, as well as dislocation analyzation using TEM. To compare these results with hcp structured alloys, the equiatomic HEA YGdTbDyHo was selected. The focus of examinations lies on the entropy affecting mechanical properties according to different crystal structures. Furthermore, the oxidation behavior of the YGdTbDyHo alloy is investigated.
Using induction levitation melting the elements were melted under argon and then drop casted in a copper mold to get a homogeneous polycrystalline alloy with a grain size of 100 µm. The miniature specimens for mechanical and oxidation testing are prepared by electrical discharge machining. The tensile tests were carried out from room temperature up to 650°C in air. By using a Netzsch DSC/DTA device the oxidation behavior of the alloy was tested from 500 to 700 °C. Furthermore, the microstructural characterization was done by SEM, EDS, and EBSD.
We identify homogeneous, polycrystalline, single phase microstructures for the hcp HEA. Furthermore, we are able to compare the results of mechanical characterization and microstructural investigations of all three HEA with different crystal structures.
| Speaker Country | Deutschland |
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