On the interaction of solute atoms with circular inhomogeneity and edge dislocation

Abstract

A two-dimensional elastic solution for the stress field of a line dilatation near a circular inhomogeneity is obtained. A line dilatation is used to represent a row of solute atoms, referred to as a solute rod. The image effect is investigated with an especial attention. It is shown that a soft inhomogeneity attracts solute rods and a hard inhomogeneity repels solute rods. Based on this, the interactions of solute atoms with inhomogeneity-edge dislocation are studied by inserting more solute atoms into the matrix one-by-one, with an especial focus on the distribution of solute atoms (rods) around inhomogeneity and edge dislocation. As two typical applications of the present method, two simple cases are analyzed in details, with the inhomogeneity considered as a nano-void and a hard nano-fiber, respectively. It is shown that the equilibrium concentration distribution of solutes near an inhomogeneity is non-local, which not only depends on the local hydrostatic stress but also on the hydrostatic stress in the adjacent region. Besides, the shear stress on an edge dislocation, generated by hydrogen atmospheres between a circular nano-void/fiber and the dislocation, is calculated numerically. The results show that the hydrogen atmosphere around dislocations can shield the long-range elastic interaction between dislocations and other internal stress sources, supporting the so-called hydrogen enhanced localized plasticity.