On the Characteristics and Role of Cottrell Co-Segregations of Carbon and Hydrogen in Strain Aging and Embrittlement of a Number of Steels

The work is devoted to the study of the characteristics of Cottrell’s phase-like “atmospheres” (carbohydride-like cosegregations of carbon and hydrogen) on dislocations in the martensitic and ferritic components in high-strength austenitic steel with transformation-induced plasticity due to the problems of aging, hydrogen embrittlement and degradation of a number of steels during operation. Particular attention is paid to in-depth processing (new technique) and analysis of the thermal desorption spectra of hydrogen for a number of steels and iron (as a reference material). The methods of thermodynamic analysis, the methodology for determining the thermodynamic characteristics (hydrogen concentrations, activation energies and rate constants of desorption processes) and the nature of “hydrogen traps” by analyzing the most representative thermal desorption data, comparing with the corresponding data obtained by three-dimensional atomic probe tomography, and also comparisons with the corresponding theoretical data. The conducted studies have shown the possibility of the formation of Cottrell carbohydride-like cosegregations of carbon and hydrogen on dislocations in martensitic and ferritic phases in high-strength austenitic steel with high plasticity induced by transformation, in particular, they made it possible for the first time to determine the binding energies of hydrogen with carbohydride-like cosegregations of carbon and hydrogen on dislocations in martensitic and ferritic phases.