Observations during in situ straining experiments on stoichiometric Ni3Al in a transmission electron microscope were presented showing that a non-conservative loop generation mechanism operates in highly-deformed slip bands. Apparently, after passage of many superlattice dislocations the antiphase boundary energy in the slip band was lowered, super-partial separations increased, and some defects (such as vacancy and anti-site) coalesced and aided the formation of the loops. These observations correlate well with recent suggestions that non-planar antiphase boundaries were present and could glide. Similar experiments in alloys that do not order do not produce such loops. These loops serve as pinning points to passage of subsequent dislocations. The separations of super-partial dislocations measured under load were greater than those measured in bulk deformed but unloaded specimens.

Slip-Plane Disordering in Stoichiometric Ni3Al. Horton, J.A., Baker, I., Yoo, M.H.: Philosophical Magazine A, 1991, 63[2], 319-35