|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Mechanical Behavior at the Nanoscale IV
||Diffusive Plasticity in Nanometer-sized Metallic Crystals
||Scott Mao, Li Zhong, Frederic Sansoz, Yang He, Chongmin Wang, Ze Zhang
|On-Site Speaker (Planned)
In nanocrystalline (NC) materials, dislocation plasticity and grain-boundary-mediated diffusive plasticity are generally viewed as two major competing mechanisms of plastic deformation. Given the similar roles that surfaces and interfaces play for both dislocation nucleation and diffusive plasticity, such competition could also govern the plastic deformation of nano-sized metals. Thus, similar to the case in NC materials, the strength of small-volume materials is expected to depend closely on specimen size, where the Hall-Petch-type relationship between crystal size and strength in the dislocation-plasticity-dominated regime converts to an inverse Hall-Petch-type relationship when diffusive processes dominate plastic deformation in the lower nanoscale. Here, by performing in situ atomic-scale transmission electron microscopy, we report unusual room-temperature super-elongation without softening in face-centered-cubic silver nanocrystals, where crystal slip serves as a stimulus to surface diffusional creep. This work provides insight into the atomic-scale coupled diffusive–displacive deformation mechanisms, maximizing ductility and strength simultaneously in nanoscale materials.
||Planned: Supplemental Proceedings volume