|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Mechanical Behavior at the Nanoscale III
||Structure-mechanical Property-deformation Mechanism Relationship in Nanotwinned FCC Metallic Nanowires
||Jiangwei Wang, Frederic Sansoz, Ting Zhu, Ze Zhang, Scott X. Mao
|On-Site Speaker (Planned)
Using gold nanowires as example, we thoroughly investigated the structure-mechanical property-deformation mechanism relationship in nanotwinned FCC metallic nanowires via the integrated studies of in-situ nanomechanical testing and atomistic modeling. As the twin size is decreased, the nanotwinned gold nanowires demonstrate a strong Hall-Petch type relationship in the elastic strain limit and a remarkable ductile-to-brittle transition. In-situ observations and atomistic modeling revealed that the ductile-to-brittle transition is governed by the heterogeneous-to-homogeneous dislocation nucleation transition. In nanowires with low density twins, the deformation is controlled by the heterogeneous nucleated dislocations from free surface, which can strongly interact with each other or twin boundaries and form the high-ordered defects (e.g. dislocation-originated stacking fault tetrahedra), contributing to the strain hardening and plasticity; in nanowires with ultrahigh density twins (<3 nm), the homogeneous nucleation of dislocations controls the onset of yielding, which further leads to the shear localization and detwinning, inducing the brittle fracture.
||Planned: A print-only volume