Engineering Physics Annotation << Back The Effect of Infl uence Plastic Deformation on the Microstructure and Mechanical Properties of Rail Steel Aksenova K.V., Vashchuk E.S., Iоnina A.V. Using the methods of scanning and transmission electron microscopy, the analysis of the evolution of the structure and defective substructure of rail steel under uniaxial compression to the degree of 50 % was carried out. It was found that the deformation hardening of rail steel occurs in stages. At the initial stage (ε = 15 %) It is caused by fragmentation of pearlite grains, accompanied by a decrease in dislocation density. With a further increase in deformation (ε > 15 %), grain fragmentation increases, and the dislocation density reaches saturation. At the same time, the cementite plates are destroyed by dissolution and cutting by mobile dislocations. On the basis of data on structural-phase states and defective substructure of rail steel obtained by methods of modern physical materials science, a quantitative analysis of the hardening mechanisms was carried out. It was shown that at the initial stage (ε = 15 %), the main hardening factor is the presence of lamellar perlite grains, and at high degrees of deformation (ε > 15 %), hardening by incoherent particles of the carbide phase. An assessment of the total yield strength of steel was also carried out in the fi rst approximation, based on the principle of additivity, which assumes the independent action of each of the hardening mechanisms. A good qualitative agreement was found between the experimentally obtained and theoretically calculated values of steel strength. Keywords: rail steel, deformation, uniaxial compression, structure, dislocation substructure, hardening mechanisms, additive yield strength. DOI: 10.25791/infi zik.2.2024.1383 Pp. 08-16.