Dislocation character transition and related mechanical response in a body-centered cubic single crystal

In situ compression of a body-centered cubic single crystal Fe–3% Si pillar in transmission electron microscopy (TEM) by scanning TEM mode was performed to observe a single dislocation moving through the pillar in real time. The deformation is characterized by a series of pronounced pop-ins, which are accompanied by increases in stress. It is shown that these stress increases are caused by the change from an edge dislocation dominated process to a screw dislocation dominated process.