| About this Abstract |
| Meeting |
2021 TMS Annual Meeting & Exhibition
|
| Symposium
|
Defect and Phase Transformation Pathway Engineering for Desired Microstructures
|
| Presentation Title |
Evolution of Metastable Grain Boundaries and Its Implications on Nanocrystals’ Hardness Variation |
| Author(s) |
Zhitong Bai, Glenn Balbus, Daniel Gianola, Yue Fan |
| On-Site Speaker (Planned) |
Yue Fan |
| Abstract Scope |
Recent experiments show that nanocrystals can be rejuvenated by pulsive femtosecond laser and their hardness can be effectively tuned. However, a mechanistic understanding on such phenomenon remains unclear. Here we investigate the evolution of a multiplicity of metastable grain boundaries in Cu under fast driving conditions using atomistic modeling techniques. A universal hysteresis is observed, and the GB is driven to a higher energy state after pulsive stimuli. Using enhanced data-mining algorithm to analyze the annealing behavior of GBs at various conditions, we construct a high-resolution pixel map for GB’s energetic evolution, showing that it is divided into an ageing regime and a rejuvenating regime over the energy—temperature space. The ageing/rejuvenating origin is attributed to the energy imbalance during the interchanges between the GB’s metastable states. A self-consistent kinetic equation is derived to capture the GB’s energetic and mechanical responses to external stimuli, which can explain the experimental observation. |
| Proceedings Inclusion? |
Planned: |