The interaction of parallel edge dislocations with a simple tilt dislocation wall

Abstract

An elastic theory analysis of the interaction of a dislocation wall (tilt substructure boundary) with parallel approaching dislocations whose slip vectors are the same as those of the dislocations in the wall is reported. It is found that such a wall fully or partially pinned is a less effective barrier for the penetration of dislocations than a single pinned dislocation on the same slip plane as the approaching dislocation. Quantitative results for the equilibrium positions of the free dislocations in the wall and the forces exerted on the approaching dislocation in various cases are presented. Free dislocations in the wall usually reduce the resistance of the wall to the penetration of approaching dislocations. The interaction between a wall and a solute atom is found to be less than that between the single nearest dislocation with the same solute atom. It is suggested that the experimental evidence which leads to the concept of hardening by substructures of this kind needs further interpretation. The segregation of vacancies and solute atoms to the dislocations probably plays a more important role in the hardening effect than the appearance of substructure.