In situ transmission electron microscopy of the interaction between a moving dislocation and obstacles of dislocation character in pure iron

In this study, we report our observation of the interaction between a moving dislocation and an obstacle of dislocation character in pure bcc-Fe using a TEM in situ straining experiment at room temperature. Our observations reveal that the interaction of a 1/2111 dislocation with a dislocation debris leads to a dislocation loop at the obstacle by Orowan mechanism. Hence, the strength of these obstacles is estimated to be in the range of Gb/L, which is higher than the strengthening induced by different nanometric defects of similar size.