A Quantitative Estimation of Specific Internal Stress Fields in Cyclically Deformed Nickel

Abstract

As a characteristic part of the internal stress field of fatigued f.c.c. metals the special stress field is considered which is correlated to the dislocations moving within a loading cycle in the dislocation-poor regions. For a quantitative estimation of this stress field (termed as polarization stress field) computer calculations are made for idealized dislocation arrangements. These arrangements are based on the idea of shuttling and separation (polarization) of dislocation groups of different signs. The results show that the polarization stress field can be divided into a half-macroscopic part strongly polarization-dependent (with a spatial distance of its maximum values in the order of the dimensions of the dislocation-poor regions) and into a nearly polarization-independent part (with a spatial distance of its maximum values in the order of the mean distance of the dislocations in a group).