| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Multi-Principal Element Alloys II
|
| Presentation Title |
J-30: Effects of Oxygen Interstitials on Phase Stability and Phase Evolution in the HfNbTaTiZr RMPE Alloy |
| Author(s) |
Leah H. Mills, Ravit Silverstein, Noah R. Philips, Daniel S. Gianola, Tresa M. Pollock |
| On-Site Speaker (Planned) |
Leah H. Mills |
| Abstract Scope |
Interstitials in BCC alloys can have a major influence on phase constitution, dislocation mobility and consequently mechanical properties. However the mechanisms by which interstitials influence properties are not fully understood in refractory multi-principal element alloys (RMPEAs). The effects of dilute amounts of oxygen on phase transformation mechanisms and tensile properties are investigated in the HfNbTaTiZr (Senkov) alloy. When subjected to tensile testing at 800°C in vacuum, the alloy exhibits reduced tensile ductility. Annealing at 800°C/100h in gettered Ar followed by nanoindentation reveals soft BCC grain boundary precipitates that enable intergranular failure. Annealing in a controlled oxygen environment at 900°C induces phase separation into a BCC phase and nm-scale O' phase. The O' phase is an intermediate phase to HCP, following the Burgers transformation path. With longer oxygen exposures, O' is consumed by BCC and HCP colonies. The implications for control of constituent phases and properties in RMPEAs will be discussed. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Mechanical Properties, Characterization |