Unravelling dislocation networks in metals

Abstract

Understanding the intricate structure of dislocations in metals is a major issue in materials science. In this paper we present a comprehensive approach for the characterisation of dislocation networks, resulting in accurate quantification and significantly increasing the insight into the dislocation structure. Dislocation networks in metals consists of dislocation segments, pinned by microstructural obstacles. In the present paper a model is introduced that describes the behaviour of these dislocation segments in the pre-yield range of a tensile test on the basis of fundamental concepts of dislocation theory. The model enables experimental quantification of the dislocation density and segment length from the tensile curve. Quantitative results are shown and discussed on the development of the dislocation network as a function of increasing degree of plastic deformation, including validation and physical interpretation of the classical Taylor equation.