Abstract
The paper presents an analysis of actual knowledge of ductile fracture in carbon and microalloyed steels with tempered structure and precipitated carbides. Discussed models of local damage in microvolume, main crack propagation processes and the following fractographical fracture surface treatment are focused on the relationships between microstructure and fracture toughness of the material. Models for prediction of stress-strain behaviour and comments of their validity at given conditions of loaded material are summarized. New directions in research of local and macroscopic characteristics in prediction of ductile damage are proposed. Attention is concentrated on the research of local damage criteria considering nonhomogeneous distribution of precipitates and on the modelling of fracture surface affected by energy dissipation rate. The further study of ductile damage in particular stages of its development from nucleation to multiplied coalescence of voids and final fracture are emphasized.

Key words
ductile damage, carbides, voids nucleation, voids growth, fractography, fractal dimension, toughness

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