INTERACTION BETWEEN DISLOCATIONS AND INHOMOGENEITIES .I.

The paper discusses the interaction between an isolated screw dislocation and an elliptically cylindrical inhomogeneity contained within an infinite body subject to a uniform applied shear stress at infinity, for the case when the dislocation is external to the inhomogeneity, which is assumed to have the form of a hole or an infinitely rigid inclusion. When the cylindrical cross-section becomes a circle, it is possible to analyze the problem when the shear modul: of the two materials have different and unrestricted values, and solutions are then presented when the dislocation lies both inside and outside the circular cylinder. The theory is extended to discussion of the piling-up of screw dislocations against an infinitely rigid elliptically cylindrical inclusion contained within an infinite body subject to a uniform applied shear stress at infinity, particular attention being given to the determination of the number of dislocations in the pile-up as a function of its length, the inclusion dimensions and the magnitude of the applied stress. Earlier models, that have been used in examinations of the behaviour of dislocations in heterogeneous media, are critically discussed and are compared with the type of model used in the present paper. © 1968.