Effects of transverse perturbations on the motion of an edge dislocation

The influence of transverse perturbations on the motion of an edge dislocation is studied using the averaged Lagrangian of the Ritz-Whitham type. The dislocation is described by the Frenkel-Kontorova model with inclusion of elastic anharmonicity and lattice discreteness (acoustic dispersion). The quadratic anharmonicity and acoustic dispersion are shown to promote self-focusing of the dislocation and microcrack formation. Under certain conditions, cubic anharmonicity can stabilize transverse compression of the dislocation, which can bring about the development of "crowdion droplets." (C) 2005 Pleiades Publishing, Inc.