Geometrically Necessary Dislocations in Materials

This lecture covers the concept of geometrically necessary dislocations in materials, explaining how dislocations arrange themselves into cells and form cell walls during plastic deformation. It discusses the stages of strain hardening in single crystals, the impact of dislocation movement speed, and the role of dislocations in reducing work hardening. The lecture also explores the influence of geometric incompatibilities, the formation of dislocation loops around rigid inclusions, and the relaxation of deformation incompatibilities by geometrically necessary dislocations. Additionally, it delves into the effects of dislocation annihilation, strain gradients, and the distribution of stress in materials.