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

Abstract

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 ½⟨1 1 1⟩ 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.

Keywords:

• transmission electron microscopy (TEM)
• dislocations
• strength
• iron

Acknowledgements

We gratefully thank D. Caillard for fruitful discussions on the TEM observations. This work, supported by the European Communities under the contract of Association between EURATOM and Confédération suisse, was carried out within the framework of the European Fusion Development Agreement. The views and opinions expressed herein do not necessarily reflect those of the European Commission. The Paul Scherrer Institute is acknowledged for the overall use of the facilities.