About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Defects and Properties of Cast Metals
|
| Presentation Title |
Varying Hall-Petch and Inverse Hall-Petch Regimes in Nanocrystalline CoCrFeMnNi High-Entropy Alloys under Shock Wave Loading |
| Author(s) |
Wanghui Li, Aitken Zachary, Shuai Chen, Yilun Xu, Xinyu Yang, Qingxiang Pei, Jian Wang, Yong-Wei Zhang |
| On-Site Speaker (Planned) |
Wanghui Li |
| Abstract Scope |
Understanding the plastic and/or structural phase transformations of the materials subjected to shock wave loading is important but has not yet been well resolved. Here we report a series of nanocrystalline CoCrFeMnNi high entropy alloys under shock loading via large-scale molecular dynamic simulations, with specific attention to the material strength/hardness characterized by flow stress behind the shock wavefront. The average nanograin size is varying from 2 nm to 22 nm to reveal the grain size effect on the flow stress. The results show that, for a given grain size, the nanocrystalline CoCrFeMnNi HEA shows a transition from strain-hardening to strain-softening with the increasing shock intensity due to the competing effect of increasing high hydrostatic pressure and high temperature under shock compression, while for a given shock intensity the flow stress shows a transition from Hall-Petch (HP) relationship to Inverse Hall-Petch (IHP) relationship due to competing deformation dominated mechanisms changing from partial dislocation-mediated plasticity to grain boundary- dominated plastic deformation. More importantly, the critical grain size for the transition from HP to IHP relationship is decreased with increasing shock intensity, which is attributed to the competing effects of high hydrostatic pressure and high temperature in softening and hardening regimes, respectively. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Entropy Alloys, Other, |