Mechanisms for the collapse and absorption of truncated stacking-fault tetrahedra by approaching dislocations were proposed. Both the self-energy and the elastic interaction energy in a straight-dislocation/stacking-fault tetrahedra system were calculated analytically. Although an isolated perfect, or truncated, stacking-fault tetrahedron was often more stable than a perfect dislocation loop or Frank sessile loop, it could become metastable under the influence of the strain fields of surrounding dislocations. Interactions between incident dislocations and stacking-fault tetrahedra could cause an instability of the perfect stacking-fault tetrahedron relative to a truncated stacking-fault tetrahedron, Frank sessile loop and perfect dislocation loop. In general, the interaction between a single stacking-fault tetrahedron and a single dislocation was found to be too small for thermal activation to overcome the elastic barriers between a metastable truncated stacking-fault tetrahedron and a stable unfaulted loop. Pinning through core reactions and dislocation pile-ups, in certain glide systems approaching the stacking-fault tetrahedron, were shown to lower the activation barriers considerably. These collapse and absorption mechanisms could explain the production of defect-free channels in irradiated materials.

Interaction of Glissile Dislocations with Perfect and Truncated Stacking-Fault Tetrahedra in Irradiated Metals. M.Hiratani, H.M.Zbib, B.D.Wirth: Philosophical Magazine A, 2002, 82[14], 2709-35