|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Mechanical Behavior at the Nanoscale IV
||Deformation Twinning in BCC Nanocrystals: Atomistic Modeling and In Situ Experiment
||Yin Zhang, Jiangwei Wang, Li Zhong, Christopher Weinberger, Scott Mao, Ting Zhu
|On-Site Speaker (Planned)
Twinning is a fundamental deformation mode that competes against dislocation slip in crystalline solids. In metallic nanostructures, plastic deformation requires higher stresses than those needed in their bulk counterparts, resulting in the ‘smaller is stronger’ phenomenon. Such high stresses are thought to favor twinning over dislocation slip. Deformation twinning has been well documented in face-centered cubic (FCC) nanoscale crystals. However, it remains less understood in body-centered cubic (BCC) nanoscale crystals. Here, by combining atomistic simulations and in situ high-resolution transmission electron microscopy, we show that twinning is the dominant deformation mechanism in nanoscale crystals of BCC tungsten and tantalum. We find that the competition between twinning and dislocation slip can be mediated by sample size and loading orientation, which is attributed to the competing nucleation mechanism of defects in nanoscale BCC crystals. Our work provides new insights into the deformation mechanism in BCC nanocrystals.
||Planned: Supplemental Proceedings volume