A computer simulation study of dislocation motion in the modified Frenkel-Kontorova model

Abstract

In this thesis, the motion and vibration characteristics of edge dislocations are investigated. Topics included, are shear stress-dislocation velocity relation; effects of model parameters and phenomenological damping on the dislocation motion; motion of a dislocation in a lattice with some impurities such as one or two fixed atoms; vibration characteristics of pinned dislocations; effects of temperature, damping and geometric parameters on the vibration characteristics of dislocations. The importance of this subject is due to the major role of dislocations on the plastic deformation of materials. By the improvement of knowledge about the dislocation behaviour, it would be possible to produce more appropriate materials for engineering use. The model is a two-dimensional, atomistic one. For every atom on the lattice, the governing equation of motion is derived, and it is solved asa function of time, numerically. To perform the calculations, a computer program is used. The results obtained for several parameters are presented, and a discussion about the results is included. At the end of the thesis, a list of recommendations for a continuation of this study is given.