| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond V
|
| Presentation Title |
Mediating Plasticity in High-Entropy Alloys with High Stacking -Fault Energy via Nanotwins/9R under Extreme Conditions |
| Author(s) |
Aomin Huang, Enrique J. Lavernia, Marc A. Meyers, Carlos J. Ruestes, Mingjie Xu |
| On-Site Speaker (Planned) |
Aomin Huang |
| Abstract Scope |
The plasticity of face-centered cubic (FCC) high-entropy alloys (HEAs) with high stacking fault energy (SFE) is primarily governed by full dislocation glide due to the high energy barrier required to nucleate partial dislocations. Here, nanoscale deformation-induced twins and 9R (a periodic faulted structure) were directly observed under microscopy in a high (SFE) HEA after extreme deformation; these two components enable the tailoring of the plastic deformation behavior.The development of 9R is related to a special partial dislocation activity that involves the cooperative activation of partial dislocations. This mechanism is manifested by both detwinning and direct emission from the grain boundaries when subjected to high strain rate and high shear stress, regardless of the strong energy barrier that has to be overcome. Therefore, besides the well-studied martensitic transformation and associated dislocation activity, the newly discovered 9R phase creates a new pathway to mediate plastic deformation. |