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Abstract: Methods of modern physical materials science are used to study the evolution of structural-phase states and dislocation substructure of rail steel under uniaxial compression deformation up to 50%. The revealed fragmentation of pearlite grains becomes more expressed with increasing deformation, and the fragmentation of cementite plates with the fragment size of 15–20 nm weakly depends on the degree of deformation. The change in the scalar and excess dislocation density with increasing deformation is analyzed. Sources of internal stress fields are identified and classified. The data obtained formed the basis for a quantitative analysis of the mechanisms of hardening of rail steel at degrees of compression deformation of 15, 30, and 50%. The contributions to strengthening caused by friction of the matrix lattice, dislocation substructure, fragment boundaries, carbide particles, internal stress fields, solid-solution strengthening, and the pearlite component of the steel structure are estimated. The primary mechanism of metal hardening at the deformation of 50% is hardening by incoherent particles and elastic internal stress fields. Using the additivity principle, which assumes the independent action of each of the hardening mechanisms, the dependence of the total yield strength of rail steel on the degree of compressive deformation is estimated.

Abstract: An Al–Fe–Cr–Co–Ni high-entropy alloy (HEA) coating is deposited on a substrate made of 5083 alloy using the cold metal transfer (CMT) technology (wire-arc additive manufacturing (WAAM) in combination with welding surfacing). The HEA alloy has a nonequiatomic composition. The modern physical materials science methods are used to analyze the structure, phase and elemental compositions, defect substructure of the coating–substrate system. It is shown that he elemental and phase compositions, the defect substructure of the coating are dependent on the distance from the zone of contacting the coating and the substrate. The layer with a thickness to 200 µm adjacent to the contact zone contains includes a second phase at the HEA grain boundaries rich in chromium and iron atoms. The microdiffraction analysis shows that these inclusions are Al8Cr5. It is revealed that nanocrystalline phases Al2O3and MgAlO with sizes 10–20 nm and a subgrained structure (subgrain size 140–170 nm) form in the zone of mixing the coating and substrate. The structure of the I type is characterized by inhomogeneous distribution of chemical elements in HEA; there are regions of lammelar shape enriched in Cr atoms and the regions of spherical shape enriched Ni, Fe, and Co atoms. Nanosized (NiCo)3, Al4, and Al13Fe4particles are arranged along the subgrain boundaries of the system. The physical mechanisms of increasing the material hardness in the coating-substrate contact are discussed.

Abstract—: Steel 45 surface is aluminized by electroexplosive alloying. The aluminized surface is treated by an electron beam. The structure and mechanical properties of the surface layer are studied. The electroexplosive is shown to lead to the formation of a high-porous coating on the steel surface. The subsequent electron-beam treatment in a mode of melting the surface layer is accompanied by the formation of a smooth surface, the increase in the microhardness in a layer thickness of 45–50 µm by a factor of 3.5 as compared to that of the initial material. The physical nature of the increase in the strength properties of a steel surface layer is explained.