|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Thermal and Mechanical Stability of Nanocrystalline Materials
||The Influence of Grain Boundary Segregation on the Mechanical Behavior of Nanocrystalline Metals
||Yang Zhang, Wenbo Wang, Jason Trelewicz
|On-Site Speaker (Planned)
Augmenting chemical and structural state of grain boundaries to stabilize nanocrystalline alloys can have marked impacts on the mechanical behavior. Using molecular dynamics simulations, we explore two such effects- stabilization against stress-assisted grain growth and grain boundary segregation strengthening. Surface nanoindentation on nanocrystalline Ni and Ni-P is first employed to quantify the role of competing mechanisms during stress-assisted grain growth. We attribute microstructural evolution to grain boundary-mediated deformation involving boundary migration and grain rotation. The addition of phosphorous stabilizes the boundaries against local atomic reconfigurations that facilitate these mechanisms, in turn eliminating grain growth. Second, the role of segregated solute on strength is explored in nanocrystalline Al-Mg alloys. We find that grain boundary plasticity is again suppressed by solute enrichment producing more stable interfacial configurations. The onset of grain boundary-mediated dislocation plasticity is thus delayed to larger strains, which manifests as an increase in strength far exceeding classical Hall-Petch scaling.
||Planned: Supplemental Proceedings volume