| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Multi-Principal Element Alloys II
|
| Presentation Title |
In-situ Investigation of the Initial Oxidation Steps in Refractory High-entropy Alloys by O2 Gas Exposure |
| Author(s) |
Heath Kersell, Xuesong Fan, Alexander Herman, Zongyang Lyu, Baldur Steingrimsson, Peter K. Liaw, Gregory S. Herman |
| On-Site Speaker (Planned) |
Heath Kersell |
| Abstract Scope |
Ti alloys find applications in biomedical implants and as high-temperature engine- and aerospace-components due to their low weight, corrosion resistance, low Young’s modulus, and tunable high-temperature strength and ductility. Recently, decreasing the Nb content in TiZrHfNbx alloys was shown to produce enhanced wear-resistance. Using ambient pressure X-ray photoelectron spectroscopy (AP-XPS), we elucidate the initial oxidation stages in TiZrHfNb0.3 refractory high-entropy alloys (RHEAs).
Ar+ ion sputtering revealed metal-carbide species in the as-cast alloy subsurface. Subsequent vacuum heating enriched the near-surface carbide content while the relative Ti, Zr, Hf, and Nb concentrations remained stable. In contrast, stepwise O2 exposures at 10-5 mbar suppressed the carbide content and induced surface oxidation and enrichment of Hf and Zr. We characterize the initial oxidation kinetics in this regime and demonstrate the limiting near-surface composition as a function of depth while higher O2 pressures induce the formation of a protective oxide layer on TiZrHfNb0.3 surfaces. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Entropy Alloys, Characterization, Titanium |