| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
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High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond V
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| Presentation Title |
The Role of Hafnium in the Oxidation of Hf-Nb-Ta-Ti-Zr-Al Refractory Multi-Principle Element Alloys |
| Author(s) |
Charlie Brandenburg, David Beaudry, Ben Redemann, Elaf Anber, Tyrel McQueen, Mitra Taheri, Elizabeth Opila |
| On-Site Speaker (Planned) |
Charlie Brandenburg |
| Abstract Scope |
Refractory Multi-Principal Element Alloys (RMPEAs) exhibit superior high temperature mechanical properties, but their oxidation mechanisms are not well understood. Alloys in the Hf-Nb-Ta-Ti-Zr-Al compositional space were oxidized in the temperature range of 900-1250°C for 5 to 20 hours in flowing 1%O2 (balance argon). The scales of alloys containing Hf tended to spall on cooling. However, the specific weight change and reaction depth of internal oxides in these alloys was significantly reduced relative to those without Hf. Previous oxidation studies of NbTiZr showed phase separation for Zr-O and Nb grains perpendicular to the oxidation front. Tracer oxidation of NbTiZr showed that Zr oxide grains were the primary path for oxygen ingress into the sample. In 10Hf-40Nb-40Ti-10Zr, Zr/Hf oxide grains were coarser than those of NbTiZr oxidized in the same conditions, and the depth of oxidation attack was greatly reduced. Possible mechanisms for the reduced oxidation rate will be discussed. |