| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Thermodynamics of Materials in Extreme Environments
|
| Presentation Title |
A First-principles-based Study of Oxidation Thermodynamics in Refractory High Entropy Alloys |
| Author(s) |
Adib Samin |
| On-Site Speaker (Planned) |
Adib Samin |
| Abstract Scope |
In an effort to better characterize the oxidation behavior in refractory high entropy alloys (RHEAs), interstitial oxidation was studied in a Mo-Nb-Ta-W alloy using DFT-based Monte Carlo simulations. It was found that the interstitial oxygen had comparable stability at tetrahedral and octahedral sites. The interstitial oxygen was found to arrange in ordered clusters and was associated with slightly enhanced mechanical properties. The solubility of the interstitial oxygen in the alloy was found to decrease with temperature. Moreover, the thermodynamics of Ti-Nb alloys and their oxides were studied as a step towards improving our understanding of the oxidation behavior of RHEAs. The presence of titanium was found to favor the formation of TiO2 over Nb2O5 in large regions of the Ellingham diagram thereby contributing to enhanced oxidation resistance in Nb-containing alloys since Nb2O5 is typically associated with scale spallation and pore formation due to its anisotropic thermal expansion. |