About this Abstract |
Meeting |
2nd World Congress on High Entropy Alloys (HEA 2021)
|
Symposium
|
2nd World Congress on High Entropy Alloys (HEA 2021)
|
Presentation Title |
Cross-kinks Control Screw Dislocation Strength in Equiatomic bcc Refractory Alloys |
Author(s) |
Xinran Zhou, Sicong He, Jaime Marian |
On-Site Speaker (Planned) |
Xinran Zhou |
Abstract Scope |
Refractory multi-element alloys (RMEA) with bcc structure have been the object of much research over the last decade due to their high potential as candidate materials for high-temperature applications. It is known that the standard model of bcc plasticity based on thermally-activated screw dislocation motion cannot explain the observed temperature dependence of bcc RMEA strength. In this work, we quantify the contribution of screw dislocations to the strength of equiatomic Nb-Ta-V alloys using a kinetic Monte Carlo model fitted to solution energetics obtained from first principles. We find that chemical energy fluctuations along the dislocation line lead to measurable concentrations of cross kinks in equilibrium. Our simulations (i) confirm that the evolution of cross kinks and self-pinning are behind the so-called ‘cocktail’ effect in this alloy, and (ii) substantiate the notion that screw dislocations may not be responsible for the high temperature strength of bcc RMEA. |
Proceedings Inclusion? |
Undecided |