A new type of 0 0 1 junction observed in a (B2) Fe-Al-Ni-B alloy by TEM in situ straining

Abstract : Single crystal foils of an FeAl alloy containing Ni and B are strained at elevated temperatures in an in situ dedicated transmission electron microscope (TEM). The observed characteristic "fork-shaped" dislocation configurations are shown to be a kind of "0 0 1 junction". This junction comes from a reaction between two 1 1 1 superdislocations gliding on different {1 1 2} planes; it results in the presence of a long and sessile edge 0 0 1 dislocation along the intersection of the glide planes. Several hypothetical core structures of such a junction are proposed and their possible effects on macroscopic mechanical properties of the alloy are discussed.