|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Mechanical Behavior at the Nanoscale III
||W-8: Crystal Size Effect on Twinning of Magnesium Microcrystals
||Gi-Dong Sim, Kelvin Y. Xie, Steven Lavenstein, Kevin J. Hemker, Jaafar A. El-Awady
|On-Site Speaker (Planned)
Deformation twinning plays an important role during plastic deformation of hcp metals due to insufficient slip systems at room temperature to accommodate deformation by slip alone. Here we report the room temperature plastic response of a-axis oriented magnesium microcrystals. Single crystal micropillars with size ranging from 2 μm to 23 μm were fabricated using FIB milling, then tested by in-situ SEM nanoindentation. Crystal size effect on the transformation of deformation mechanisms is reported. EBSD analysis of the deformed pillars indicates that the deformation is governed by twinning. Once twin propagates over a critical thickness of the pillar height, excessive basal slip occurs in the twinned region. Stress required for twin propagation was found to increase with decreasing crystal size. An anomalous increase in strain hardening was observed for larger microcrystals, induced by twin-twin interactions. Results are compared to bulk Mg single crystals to further understand hardening induced by twin-twin interaction.
||Planned: A print-only volume