|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||In Situ Observation of Shear-driven Amorphization Process in Silicon Crystals
||Scott Mao, Yang He, Feifei Fan, Chongmin Wang, Ting Zhu
|On-Site Speaker (Planned)
This talk will be based on a recent publication on Nature Nanotechnology by Yang He, Li Zhong, F. Fan, Chongmin Wang, Ting Zhu and Scott X. Mao. Amorphous solids usually form under extreme driven conditions such as melt quenching, irradiation, shock loading or severe mechanical deformation, which impose significant challenges on direct observation of the amorphization process. As such, a dynamic, atomistic characterization of how amorphous phase form has remained elusive. Here, by using in situ atomic-scale TEM, we directly observe that shear-driven amorphization occurs in a dominant shear band starting with the diamond-cubic (dc) to diamond-hexagonal (dh) phase transition and then proceeds by dislocation nucleation and accumulation in the newly formed dh-Si phase. The process then leads to the formation of an amorphous Si (a-Si) band, embedded with dh-Si nanodomains. The amorphization of dc-Si via an intermediate dh-Si phase is a previously unknown pathway of solid-state amorphization.
||Planned: Supplemental Proceedings volume