| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Deformation and Transitions at Grain Boundaries VII
|
| Presentation Title |
Mechanistic Transitions Underpinning Grain Boundary Segregation Strengthening in Nanocrystalline Alloys |
| Author(s) |
Jason Trelewicz |
| On-Site Speaker (Planned) |
Jason Trelewicz |
| Abstract Scope |
Grain boundary segregation has been leveraged to stabilize nanocrystalline materials and exploit the shift to interface mediated mechanisms for achieving ultrahigh strength. Augmenting the chemical state of the boundaries has also been shown to produce strengthening increments that exceed classical Hall-Petch predictions. In this presentation, we employ molecular dynamics simulations of nanocrystalline Al-Mg alloys to quantify the mechanisms responsible for this unexpected increase in strength – denoted grain boundary segregation strengthening – in the context of fundamental changes in grain boundary properties upon alloying. We find that grain boundary microplasticity at low strains is suppressed by solute enrichment producing more stable interfacial configurations, which delays the onset of grain boundary mediated dislocation slip and promotes an increase in strength. Following the yield point, the interaction of lattice dislocations with grain boundary solute atoms reduces the strain accommodated through dislocation plasticity, thus shifting plastic strain accommodation to the grain boundaries. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |