Core structure, dislocation energy and Peierls stress for edge dislocations with (0 0 0 1) and slip planes in α-Zr

Atomic-scale simulations of edge dislocations of the 1 / 3 1   1   2 ¯   0 ( 0   0   0   1 ) and 1 / 3 1   1   2 ¯   0 { 1   1 ¯   0   0 } slip systems have been carried out using a Finnis-Sinclair-type interatomic potential for α-zirconium. The distribution of atomic displacements in the dislocation core shows that in this model the edge dislocation in the basal plane dissociates into two Shockley partials whereas the dislocation in the prism plane remains undissociated. The effective core radius and core energy are estimated, and dislocation response to increasing applied shear strain is investigated. The core properties and the critical stress for dislocation glide (Peierls stress) depend sensitively on whether the core extends or not.