The collapse of stacking-fault tetrahedra by gliding dislocations was observed in in situ straining experiments in a transmission electron microscope. A stacking-fault tetrahedron was collapsed by intersection with a gliding perfect dislocation: only the base portion divided by the gliding plane of the dislocation annihilated, while the apex portion remained intact. As a result of analysis on evolution of atom configuration induced by intersection with perfect dislocation in stacking-fault tetrahedra, it was found that an unusual atom configuration inevitably appeared in one of the ledges formed on stacking-fault planes, which was traditionally called I-ledge: the atoms on adjacent (111) planes were overlapping each other. The overlapping configuration provides a strong repulsive force, being a conceivable driving force to induce a chain reaction of atom displacements that collapses the stacking-fault tetrahedra base portion.

The Collapse of Stacking-Fault Tetrahedra by Interaction with Gliding Dislocations. Y.Matsukawa, Y.N.Osetsky, R.E.Stoller, S.J.Zinkle: Materials Science and Engineering A, 2005, 400-401, 366-9