It was recalled that stacking fault tetrahedra were formed under irradiation in face-centered cubic metals and alloys. The high number density of tetrahedra observed suggested that they should contribute to radiation-induced hardening and therefore be taken into account when estimating the mechanical property changes of irradiated materials. The key problem was to describe the interaction between a moving dislocation and an individual stacking fault tetrahedron which was distinguished by a size of 1 to 10nm. Atomistic simulations were made of edge and screw dislocations interacting with stacking fault tetrahedra of various sizes at divers temperatures and strain rates. Five possible interaction outcomes were identified. They involved partial absorption, or shearing or restoration of stacking fault tetrahedra. The mechanisms that gave rise to these processes were described and their dependences upon parameters such as stacking fault tetrahedra size, dislocation/stacking fault tetrahedra geometry, temperature and stress/strain rate were determined. Mechanisms were considered that helped to explain the formation of defect-free channels cleared by gliding dislocations; as observed experimentally.

Atomic-Scale Study of Dislocation-Stacking Fault Tetrahedron Interactions - Part I - Mechanisms. Y.N.Osetsky, D.Rodney, D.J.Bacon: Philosophical Magazine, 2006, 86[16], 2295-313