About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
Advances in Multi-Principal Elements Alloys X: Structures and Modeling
|
Presentation Title |
A-12: KMC Modeling of Screw Dislocation Strength in Equiatomic bcc Refractory Alloys |
Author(s) |
Xinran Zhou, Jaime Marian, Sicong He |
On-Site Speaker (Planned) |
Xinran Zhou |
Abstract Scope |
Refractory multi-element alloys with bcc structure display a
remarkable strength at high temperatures, which cannot be explained by the standard model of bcc plasticity based on thermally-activated screw dislocation motion. Several works point to chemical energy fluctuations as an essential aspect of RMEA strength that is not captured by standard models. Our work quantifies the contribution of screw dislocations to the strength of equiatomic Nb-Ta-V alloys using a kMC model. We find that chemical energy fluctuations along the dislocation line lead to measurable concentrations of kinks in equilibrium in a wide temperature range. A fraction of these form cross-kink configurations, which are found to control screw dislocation motion and material strength. Our simulations confirm that (i) the evolution of cross kinks and self-pinning are strong contributors to the strength of this alloy at low temperature, and (ii) screw dislocation plasticity alone cannot explain the high temperature strength of bcc RMEA. |
Proceedings Inclusion? |
Planned: TMS Journal: Metallurgical and Materials Transactions |
Keywords |
Computational Materials Science & Engineering, Modeling and Simulation, Mechanical Properties |