About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Progress in High Entropy Materials: Integrating Experiments, Computation, and Machine Learning
|
| Presentation Title |
Lattice Distortion–Driven Transition from Screw to Edge Dislocation Glide Enhances High-Temperature Strength Retention in Refractory High-Entropy Alloys |
| Author(s) |
Mingwei Zhang, Tamanna Zakia, Ayeman Nahin, Dunji Yu, Michael Lau, Jacob Pustelnik, Juntan Li, Mason Kincheloe, Lia Amalia, Yan Chen, Peter K. Liaw, Haixuan Xu |
| On-Site Speaker (Planned) |
Mingwei Zhang |
| Abstract Scope |
Refractory high-entropy alloys (RHEAs) can exhibit good strength retention at elevated temperatures, yet the underlying deformation mechanisms remain debated. In this talk, we show that temperature and lattice distortion jointly drive a transition in the dominant dislocation glide mechanism from screw- to edge-dislocation control, fundamentally altering high-temperature strengthening behavior. Using a combination of room-to-high-temperature tensile testing, in-situ neutron scattering under load and heating, scanning transmission electron microscopy, as well as molecular dynamics simulations, we identify a regime in which edge dislocations become the rate-limiting carriers of plasticity. This transition is promoted by severe lattice distortion and atomic-scale volume misfit, which preferentially interact with edge dislocations and suppress their mobility below that of screw dislocations. As a result, strength becomes less thermally sensitive, enabling enhanced strength retention at elevated temperatures. These findings establish dislocation-mechanism transitions as a key design principle for developing next-generation refractory high-entropy alloys for high-temperature structural applications. |
