CYCLIC PLASTIC DEFORMATION AND INITIATION OF CRACKS IN METALS

摘要

The initiation and early propagation of fatigue cracks are smoothly consequential processes without any clear border between them. At present there is no generally accepted quantitative description of the initiation process and the following propagation of the microstructurally small cracks. Thus, any numerical analysis of the initiation of cracks must be preceded by deeper understanding of physical mechanisms. The aim of the paper is to offer an overview of the present state of the art in the fatigue crack initiation in metals. The following items will be treated: (ⅰ) sites of crack initiation, (ⅱ) prerequisites for crack initiation, (ⅲ) mechanisms of crack initiation and (ⅳ) end of initiation stage and beginning of the propagation stage.