This paper presents calculations of screw dislocation cross slip in copper and nickel systems, using the nudged elastic band method and interatomic potentials based on the effective-medium theory. The validity of recent attempts to predict cross slip activation energies by ‘elastic scaling’ between fcc metals is investigated, finding that reasonable predictions can be made using the approach suggested by Rasmussen [T. Rasmussen, Phil. Mag. A 80 (2000) 1291]. The experimentally determined cross slip activation energy and the minimum stable screw dislocation dipole height for copper are explained on the basis of cross slip of jogged screw dislocations.
In this study, a dislocation-based model is presented for investigating the evolution of microstructure and mechanical properties of thin lms during a wide range of straining. The model is applied to the High Pressure Torsion (HPT) process of thin nickel disks that provides valuable information on the evolution of material parameters during deformation. The model considers a free surface theory for thin lms and can explain the size e ect phenomenon in agreement with previous reported trends in literature.
We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.