Recently, the team of Academician Zhang Ze and Researcher Wang Jiangwei of the Electron Microscope Center of Zhejiang University cooperated with the team of Professor Zhu Ting of Georgia Institute of Technology to observe the nucleation and growth of anti-twin crystals in tungsten nanowires (body-centered cubic structure metals) with a diameter less than 20 nm for the first time by using the PicoFemto series TEM-STM in-situ transmission electron microscope sample rods of Ze You Technology, combined with molecular dynamics theory simulation and density functional theory calculation, the mechanism of anti-twinning behavior is theoretically explained. The work was published in SCIENCE ADVANCES, a subsidiary of Science, under the title of "Anti-twinning in nanoscale tungsten. DOI: 10.1126/sciadv.aay2792

original link: during the anti-twinning of https://advances.sciencemag.org/content/6/23/eaay2792.full

, continuous 1/3<111> shear occurs on adjacent {112} planes instead of the reverse 1/6<-1-1> shear in ordinary twinning. The asymmetry of this atomic scale shear path leads to the appearance of anti-twinning more difficult than ordinary twinning deformation. They found that due to the limited number of plastic shear carriers in a small crystal volume, anti-twinning can become active in nanometer-sized BCC crystals under high stress. This work provides a new idea for the study of the size-dependent deformation of small-volume BCC crystals, and has guiding significance for the use of unconventional deformation mechanisms to achieve high-mechanical preforming of nanomaterials.

Figure 1 Experimental method

In this experiment, a tungsten needle is passed through the PicoFemto®In-situ TEM-STM electrical measurement The piezoelectric manipulation module of the sample rod is accurately docked to the tungsten rod on the other side. Under the action of an applied voltage, the two achieve high-precision in-situ welding in the TEM to form a tungsten nanowire. After the formation of nanowires can continue to use PicoFemto®In-situ TEM-STM Electrical Measurements Physical Properties Measurement and Mechanical Loading Function of the Sample Rod The nanowires were tested and characterized in-situ.

Figure 2 TEM photos collected in situ