|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Coupling Experiments and Modeling to Understand Plasticity and Failure
||Annealing-detwinning due to Thermal Fluctuation of Incoherent Twin Boundary
||Hao Sun, Chandra Veer Singh
|On-Site Speaker (Planned)
||Chandra Veer Singh
Classical method for strengthening metal introduce internal defects and boundaries to impede dislocation gliding. However, such strategies invariably compromise ductility. This strength-ductility trade-off can be overcome by the introduction of ultra-fine twin boundaries (TBs). Such micro-structure has been successfully synthesized in chemical vapor deposited (CVD) Nickel, but with poor thermal stability. The nano-twins tend to transform into dislocation cell structures driven by the excess free energy associated with the high density of TBs. Due to the limitation of experiments, only computational simulation can uncover the atomistic mechanism of thermal detwinning and the subsequently dislocation generation.
We use molecular dynamics simulation to study annealing-detwinning in CVD Nickel. A new dislocation generation mechanism was proposed by Incoherent twin boundary (ITB) migration. Dislocation interaction and dissociation will generate immobile stair-rod dislocation. Immobile stair-rod dislocation transformed into Shockley partial dislocations which are left behind by the ITB plane.
||Planned: Supplemental Proceedings volume