| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advanced Characterization Techniques for Quantifying and Modeling Deformation
|
| Presentation Title |
Antitwinning in Nanoscale Tungsten |
| Author(s) |
Jiangwei Wang, Ting Zhu |
| On-Site Speaker (Planned) |
Jiangwei Wang |
| Abstract Scope |
Nanomaterials often surprise us with unexpected phenomena. Here we report a surprising discovery of the anti-twinning deformation, previously thought impossible, in nanoscale body-centered cubic (BCC) tungsten crystals. By using in situ transmission electron microscopy nanomechanical testing, we observed the nucleation and growth of anti-twins in tungsten nanowires with diameters less than ~ 20 nm. Anti-twinning produces a shear displacement of 1/3<-1-1-1> on every successive {112} plane, in contrast to an opposite 1/6<111> shear by ordinary twinning. This asymmetry in shear geometry leads to a much higher resistance to anti-twinning than ordinary twinning, as shown by first principles calculations. Nonetheless, anti-twinning becomes active in nano-sized BCC crystals that have limited plastic shear carriers and thus develop ultra-high stresses. This work unveils a surprising deformation mode in BCC crystals and has broad implications for harnessing unconventional deformation mechanisms to achieve high mechanical preformation by nanomaterials. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |