Electron Microscope Observation of Dislocations and Antiphase Boundaries in Iron-Aluminum Alloys

Abstract

The structure of iron rich Fe-Al alloys associated with ordering and the type of dislocations induced by cold-rolling have been investigated by transmission electron microscope observation. The 24.9∼31.0 at. % aluminum alloys are observed to have homogeneous DO 3 type order when slowly cooled from disordered state. In the 24.9 at. % aluminum alloy 1/4· a 0 ' antiphase boundaries very likely left behind 1/4· a 0 ' dislocations are observed, whereas in the alloys containing 26.3∼31.0 at. % aluminum 1/2· a 0 ' antiphase boundaries very likely left behind 1/4· a 0 ' dislocation pairs (or 1/2· a 0 ' dislocations) are observed. The composition where the type of dislocation changes coincides with that where the yield strength becomes maximum (about 26 at. % aluminum).