About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Interstitial–Metal Interactions: The Outsized Role of Small Atoms
|
| Presentation Title |
Interstitial oxygen as a design platform to redefine strength-ductility relations in refractory high-entropy alloys |
| Author(s) |
Pedro Borges, Robert Ritchie, Mark Asta |
| On-Site Speaker (Planned) |
Pedro Borges |
| Abstract Scope |
Interstitial alloying, particularly with oxygen, has been suggested to be a platform to overcome strength-ductility trade-offs in refractory high-entropy alloys (RHEAs). We present a comprehensive first-principles study detailing how oxygen can unlock unprecedented microstructural design avenues. Specifically, we show that local compositional environments in RHEAs strongly suppress oxygen segregation to screw dislocation cores, driving instead the formation of nanoscale interstitial clusters in the bulk. Monte Carlo simulations further reveal that oxygen shows kinetics fast enough for these clusters to equilibrate under conditions moderate in time and temperature. Once formed, the clusters strengthen the alloy through lattice distortions and enhance ductility by promoting strain hardening, resulting in simultaneous improvements in strength and ductility from room temperature up to elevated temperatures. Oxygen is also shown to benefit cryogenic plasticity by preventing the formation of the brittle omega phase while fostering deformation twinning. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Entropy Alloys, Modeling and Simulation, Mechanical Properties |