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Abstract—For rails of increased wear resistance and contact endurance of the DH400RK category made of E–0.9C–Cr–V–Fe hypereutectoid steel, after a tonnage of 187 million tons, the fine structure in the railhead along the central axis at distances of 0, 2, and 10 mm was analyzed using transmission electron microscopy for the four morphological components of pearlite from the rolling surface. The nonmonotonic change in scalar and excess dislocation density, fragment size, cementite particles, and internal long-range stress fields in the railhead section was analyzed.

Abstract—An attempt was made to solve the problem of creating a coating for an implant having better biological compatibility than Titanium Grade 5 medical titanium alloy. A coating of Mo–Nb composition was prepared by the electroexplosive method on Titanium Grade 5 medical titanium alloy and formed as a result of the simultaneous electric explosion of foils made of molybdenum and niobium. A set of studies was carried out to determine the structure, phase composition, and properties of the prepared coatings. It is shown that the hardness of the coating surface layer is 60% and the Young’s modulus is 43% higher than the corresponding characteristics of Titanium Grade 5 alloy. The thickness of the layer with high (relative to the substrate) values of hardness and Young’s modulus reaches 80 μm. It was found that the coating wear parameter is 1.8‑fold and the coating friction coefficient is 1.6-fold higher than the substrate wear parameter and friction coefficient. It was determined that, along with coating atoms, the surface layer comprises Al, Ti, V, O, and C atoms, indicating that the coating is doped with the substrate atoms. In the detected coating stratification by elemental composition, the top part of the coating is enriched in niobium atoms, and the bottom part is enriched in molybdenum atoms. The coating was shown to have a polycrystalline structure formed by a molybdenum-based solid solution. The bulk and the grain boundaries compose the second phase comprising α-Ti, Nb, Mo9Ti4, and NbTi4of various shapes and sizes. The phase composition studies revealed no vanadium or aluminum compounds, which reduce the biocompatibility of coatings. The detected phases comprise only molybdenum, niobium, and titanium, which are bioinert, which allows predicting higher biocompatibility compared to the that of Titanium Grade 5 medical alloy. It is recommended to use the resulting coatings for further clinical tests.

Abstract: Using the methods of scanning and transmission electron microscopy, an analysis was made of the evolution of the structure and defective substructure of rail steel under uniaxial compression up to a degree of 50%. It is revealed that the strain hardening has a multistage nature and is accompanied by a decrease in the scalar and excess dislocation density and fragmentation of pearlite grains, which increases with increasing strain. Fracture of cementite plates proceeding through the mechanisms of their dissolution and cutting by mobile dislocations is revealed. On the basis of data on the structural-phase states and the defective substructure of rail steel obtained by the methods of modern physical materials science, a quantitative analysis of the mechanisms of hardening of rail steel at degrees of compression deformation of 15, 30, and 50% was carried out. It is shown that, at the initial stage (ε = 15%), the main strengthening factor of the steel under study is the presence of lamellar pearlite grains, and at high degrees of deformation (ε = 50%), it is hardening by incoherent particles of the carbide phase. The overall yield strength of steel was estimated in the first approximation based on the additivity principle, which assumes the independent action of each of the hardening mechanisms. A good qualitative agreement between the experimentally obtained and theoretically calculated values of steel strength has been revealed.

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.

Abstract: Using wire-arc additive manufacturing (WAAM), we produced samples of Al–Co–Cr–Fe–Ni high-entropy alloy (HEA) with a grain size of 4–15 µm. Inclusions of the second phase were found along the boundaries and in the volume of the grains. The near-boundary volumes of the alloy (volumes located along grain boundaries) are enriched in chromium and iron atoms, the volume of grains is enriched in nickel and aluminum atoms, and cobalt is quasi-uniformly distributed in the alloy. The inclusions of an elongated shape are enriched in chromium, iron, and oxygen atoms and may be carbides. Microhardness, modulus of elasticity, and tribological properties of the alloy are determined and the stretch curves are analyzed. Irradiation of the HEA with a pulsed electron beam is accompanied by the release of grain boundaries from precipitates of the second phase, which indicates the homogenization of the material. High-speed crystallization of the molten surface layer of HEA samples is accompanied by the formation of a columnar structure with a submicrometer-nanocrystalline structure. The electron-beam processing decreases the microhardness of the surface layer of the alloy with a thickness of up to 90 µm, which may be due to the relaxation of internal stress fields formed in the initial material during its manufacture. Irradiation of a high-entropy alloy with an intense pulsed electron beam improves the strength and plasticity of the material, increasing the compressive strength by 1.1–1.6 times.

Abstract: A coating of high-entropy Cantor alloy FeCoCrNiMn of nonequiatomic composition was formed on a 5083 aluminum alloy substrate by wire-arc additive manufacturing (WAAM). The methods of physical materials science were applied to analyze the structure, elemental composition, microhardness, and wear resistance of the coating–substrate system. The deposition of the FeCoCrNiMn high-entropy coating on the 5083 alloy surface is accompanied by the formation of microhardness and elemental composition gradients. Microcracks and micropores were revealed in the cross section of the coating. Microhardness in the volume of the coating is 2.5–3.5 GPa and increases to 9.9 GPa at the boundary with the substrate. In the middle part of the coating, the wear factor is 2.3 × 10–4mm3/N m; the friction coefficient is 0.7. A transition layer up to 450 µm thick is formed at the interface between the coating and the substrate. We analyzed the elemental composition gradient of the transition layer and noted a high level of chemical homogeneity of the coating. The found doping of the coating with substrate elements (aluminum) leads to the formation of a FeC-oCrNiMnAl high-entropy coating, causing a lamellar structure at the interface between the transition layer and the substrate.

Abstract: A quantitative comparative analysis of the strengthening mechanisms for the surface layers of rails is carried out. It is based on the regularities in forming structure, phase composition, defective substructure, and properties of differentially hardened 100-m rails at different depths (up to 10 mm) and performed in the rail head along the central axis and along the symmetry axis of the fillet in the initial state and after various periods of extreme operation (with the handled tonnage of 691.8 and 1411 million gross tons). These regularities are identified using the methods of modern physical materials science. Contributions to strengthening due to friction of the matrix lattice, intraphase boundaries, dislocation substructure, the presence of carbide particles, internal stress fields, and solid solution strengthening of the pearlite constituent in the steel structure are assessed.

ABSTRACTThe microstructure evolution and properties variation of the surface layer of rail steel after passed 500 and 1000 million tons of gross weight (MTGW) have been investigated. The wear rate increases to 3 and 3.4 times after passed 500 and 1000 MTGW, respectively. The corresponding friction coefficient decreases by 1.4 and 1.1 times. The cementite plates were destroyed and formed the cementite particles of around 10–50nm in size after passed 500 MTGW. The early stage dynamical recrystallisation was observed after passed 1000 MTGW. The mechanisms for these have been suggested. The large number of bend extinction contours is revealed in the surface layer. The internal stress field is evaluated.This paper is part of a themed issue on Materials in External Fields.

The microstructure evolution and properties variation of the surface layer of rail steel after passed 500 and 1000 million tons of gross weight (MTGW) have been investigated. The wear rate increases to 3 and 3.4 times after passed 500 and 1000 MTGW, respectively. The corresponding friction coefficient decreases by 1.4 and 1.1 times. The cementite plates were destroyed and formed the cementite particles of around 10–50nm in size after passed 500 MTGW. The early stage dynamical recrystallisation was observed after passed 1000 MTGW. The mechanisms for these have been suggested. The large number of bend extinction contours is revealed in the surface layer. The internal stress field is evaluated.This paper is part of a themed issue on Materials in External Fields.

To clarify the mechanisms by-which current pulses affect plastic deformation, an electron-microscope study has been made of the evolution of the fine structure of steel Kh18N10T subjected to electrostimulated (current density 1200 MA/m2, frequency 200 Hz) and conventional wire-drawing at a speed of 1.88 m/sec with total reduction up to 58%. The evolution of the microstructure of steel during conventional plastic deformation of drawing is similar to that produced by conventional drawing and simultaneous current pulses. Quantitative characteristics of microstructure such as scalar dislocation density, azimuthal disorientation, and distance between subboundaries have been measured and statistically evaluated. The effect of the current is connected with the reduction of the scalar dislocation density and partial recovery of the substructure. Proposed models are supported by the data on microplastic deformation.

The effect of the concentration (C) of Ca2+ impurity ions and electric fields up to 50 kV/cm on the kinetic characteristics of the expansion of edge and screw dislocation half-loops in annealed and quenched NaCl crystals is studied. It is confirmed that 1) the concentration dependence of the rate v of expansion of screw half-loops takes the form v = v* exp (-AC1/2); 2) with increasing field strength E the velocity v increases linearly in pure NaCl crystals'; in impure crystals for E>5 kV/cm the rate of expansion of the edge half-loops increases and that of the screw half-loops diminishes as ~exp (E). The extent of the latter effect depends on the concentration of Ca2+ impurity ions in the crystals and also on their heat treatment. The exponential change in v with field E is apparently a consequence of the reorientation of the “Ca2+ ion-cation vacancy” dipoles in the electric field. The activation energy for the reorientation of the dipoles is estimated. The linear increase in the rate of expansion of the half-loops is explained as being due to the reduction in the number of steps in the dislocation under the influence of the electric field.

The method of selective etching was applied to study the influence of electric current pulses with duration 2 × 10-4 s and current density more than 20 MA/m2 on the pyramidal dislocation mobility in Zn monocrystals at 77 and 293 K. It was established that the increase of dislocation mobility under the influence of current pulses is accompanied by multiplication of dislocations at current densitiesj > 102 MA/m2. The obtained results are discussed with the account of electron-dislocation interaction, heating and Frank-Read source operation under the electron wind influence.

Selective etching at 77 K has been applied to the mobilities of pyramidal dislocations in the 11¯22<11¯23> slip system for pure Zn single crystals in the region of thermally activated motion in order to establish how the pulses affect the plasticity. The activation and statistical parameters in the dislocation motion have been related to the current density and loading on the basis of the ponderomotor forces, the thermal response and the skin effects, as well as the electron-dislocation interaction. The current effect is related to reduced probability of overcoming Peierls barriers.

Diffraction electron microscopy has been applied to the microstructure evolution in 08G2S steel after ordinary and electrostimulated drawing; the current pulses affect some fine-structure characteristics.

The results of experimental investigation of the evolution of the structure and mechanical properties of Kh18N10T steel wire subjected to normal and electrostimulated drawing at a rate of 1.88 m/sec and a total reduction of up to 75% are given. The change in yield and tensile strengths, elongation, and reduction in electrostimulated drawing characterizing the higher plasticity of the material is analyzed. The structural changes accompanying the process of electrostimulated drawing include a difference in the character of the layer work hardened in drawing, evolution of the substructure, and the appearance of re crystallization twins.

Experimental data on the evolution of the microstructure of a 17GKhAF steel wire subjected to ordinary and electrically stimulated (by a pulsed current) drawing with a total constriction of up to 35% ate outlined. The change in scalar dislocational density, volume fraction of regions with strong lattice rotation, excess dislocational density in these regions, density of twins, and azimuthal disorientation of adjacent regions of microstructure are analyzed.

For the purpose of clarification of the mechanisms of the electron-plastic effect the influence of current pulses with a length of 2·10-4 sec and a density of more than 20 MA/m2 on the mobility of pyramidal dislocations in Zn single crystals in the area of thermally activated movement at 77 and 293 K and also on their multiplication was studied by the method of selective etching. It was shown that the increase in the rate of movement of dislocations under the action of current pulses is accompanied by multiplication of the dislocations with current densities of more, than 102 MA/m2. The rules established are discussed taking into consideration the pondermotive forces, thermal effects, electron-dislocation interaction, and the work of the Frank-Reid effect under the action of the electron wind.

The dependence is investigated of the velocity of motion of edge and screw dislocations on the applied shear stress in annealed and quenched NaCl and KC1 crystals with various impurity content under the action of an electric field of up to 50 kV/cm. It is shown that in impure crystals the action of the field is determined by its effect on damping centers, while in pure crystals, by its effect on charged dislocations. The interaction force of an edge dislocation with “impurity-vacancy” dipoles of various orientation is calculated. The charge density and sign of a dislocation is estimated.

Selective etching has been applied to the mobilities of pyramidal dislocations in the {11¯22} <11¯23> system in Zn single crystals in the quasiviscous region in the simultaneous presence of mechanical treatment and current flow in order to establish the mechanisms whereby current pulses affect metal plasticity. The dislocation dynamics may be related to the current density and mechanical loading, which is examined in relation to the possible current-effect mechanisms. The dynamic retardation constant has been estimated and it has been found that the nonpolar pinch effect and direct force action from the current are decisive.

The structure, phase composition of the composite electroexplosion coating of ZnO- Ag system subjected to the irradiation by the high intense electron beam have been studied for the first time. The combined processing including the electroexplosion spraying of the coating of ZnO-Ag system and its subsequent electron beam processing results in the formation of multilayer structure of the coating. The electron beam melts and homogenizes the surface layer of the composite electroexplosion coating of ZnO-Ag system to the depth of 35-40 um. The effect of the electron beam leads to the formation of the nanocrystalline phases of Ag, ZnO, Cu, CuZn, Ag5Zn8, Cu2O, Ag2O, Cu0.67Zn0.33, AgZn. The dependences of changes in crystal lattice parameters and coherent scattering regions of the phases being formed depending on the processing regime by high intense electron beam have been found.

Studies of the phase and elemental composition of the surface layer of the copper electric contact of the KPV-604 contactor subjected to electro-explosive spraying of the composite SnO2-Ag-coating were carried out by means of transmission electron microscopy. The scale of elemental structure of the coating surface varies within a very wide interval after electro-explosive spraying - from hundreds of micrometers to tens of hundreds of nanometers. According to the morphological structure, two layers can be distinguished in the coating volume: the coating itself and the heat affected layer smoothly transferring into the bulk of the sample. A nanocrystalline structure was detected. The main phases of the coating are SnO2, Ag3Sn, Cu10Sn3, Cu3Sn, Cu6Sn5, Ag4Sn and CuO. The volume of copper adjacent to the coating has a fragmented structure indicating a high level of deformation of the sample surface layer under the electro-explosive formation of the coating.

The effect of low-energy high-current electron beams on the structure of silumin has been studied. It has been found that the electron beam treatment leads to the formation of a heterogeneous multi-layer structure in the material. A columnar crystallization structure has been observed in the surface layer. The transverse dimensions of the columns are between 400 and 600 nm, whereas the second phase interlayer dimensions are between 80 and 100 nm. The transverse dimensions of the columns at a depth of 80 to 100 um are 1.0-1.2 um. The cause of the columnar structure is the thermoconcentration-capillary instability, which leads to the formation of vortices and the displacement of the second phase particles to the columnar boundaries. The considerable thickness of the columnar crystallization layer is caused by the fact that silicon and other alloying elements influence the dependence of liquid aluminum surface tension on temperature by introducing nonlinearity. As a result, there is an effect of the "thermal drill", i.e. the formation of vortices. The formed vortices stir the melt throughout the depth, and the downward flow of the liquid moves to the center of the bath at the cooling stage, which is manifested in an increase in the thickness of the columnar crystallization layer. It manifests itself in an increase in the thickness of the columnar crystallization layer. At depths over 100 um, the fracture of silicon particles is observed as a result of differences in the elastic moduli and linear expansion coefficients of the aluminum matrix and the silicon plate.

The paper reports on coating of silumin samples with Al-Y2O3 by electric explosive alloying. When testing the micro-hardness, two appropriate processing modes of samples were revealed; the porosity of their surface profile was examined using atomic-force microscopy. A multi-layer structure was disclosed by metallographic microscopy, the thickness of each layer in the coating was determined as well. The mechanism of this structure formation was suggested.

Structural phase states and tribological properties of the coating surfaced onto Hardox 450 martensite low-carbon steel with powder wire Fe-C-Cr-Nb-W and modified by subsequent electron-beam processing are studied by methods of modern physical material science. It is shown that irradiation of [?] 5 mm thick surfaced layer with high intensity pulsed electron beams results in the formation of [?] 20 um thick surface layer with the master phases of a-Fe and NbC, Fe3C and M6C(Fe3W3C) carbides. It is established that wear resistance of the surfaced layer after electron-beam processing increases more than 70-fold relative to wear resistance of Hardox 450 steel and friction coefficient decreases significantly ([?]3-fold).

In the present work, the analysis of the structure and properties of silumin, modified by deposition of yttrium oxide on the surface by electric-explosive alloying, was made, (alloying with a droplet-plasma flow produced by the electric explosion of a conductive foil with a sample of powder material). The structure and phase composition of silumin were studied by scanning and transmission diffraction electron microscopy. Formed coatings are characterized by a high level of roughness and porosity.

The convection mixing model is proposed for low-energy high-current electron beam treatment of titanium alloys, pre-processed by heterogeneous plasma flows generated via explosion of carbon tape and powder TiB2. The model is based on the assumption vortices in the molten layer are formed due to the treatment by concentrated energy flows. These vortices evolve as the result of thermocapillary convection, arising because of the temperature gradient. The calculation of temperature gradient and penetration depth required solution of the heat problem with taking into account the surface evaporation. However, instead of the direct heat source the boundary conditions in phase transitions were changed in the thermal conductivity equation, assuming the evaporated material takes part in the heat exchange. The data on the penetration depth and temperature distribution are used for the thermocapillary model. The thermocapillary model embraces Navier-Stocks and convection heat transfer equations, as well as the boundary conditions with the outflow of evaporated material included. The solution of these equations by finite elements methods pointed at formation of a multi-vortices structure when electron-beam treatment and its expansion over new zones of material. As the result, strengthening particles are found at the depth exceeding manifold their penetration depth in terms of the diffusion mechanism.

Changes in the surface of the fractured structure of commercially pure titanium VT1-0 under treatment by low-energy high-current electron beams and the subsequent cycle fatigue to the failure were analyzed by transmission scanning and transmission electron diffraction microscopy. The increase in the fatigue life of samples in 2.2 times after treatment by electron beams was established. An assumption was made that the increase in the fatigue life of titanium, grade VT1-0, was due to the formation of a lamellar substructure conditioned by high-velocity crystallization of the titanium surface layer.

The structure-phase conditions formed during the deposition of surface coatings on Hardox 450 steel by the wire comprising C, V, Cr, Nb, W were examined by the methods of X- ray phase analysis and transmission electron diffraction microscopy. It was established that after the hardened layer was deposited, the wear-resistance increased 153 times and the coefficient of friction in the material decreased 2.5 times. It was concluded that the increased properties of the surface coating were due to the formation of martensitic structure and the occurrence of high volume fraction of carbide phase inclusions.

The studies carried out in this work target detection of changes in the surface layer of titanium alloy VT6 after electro-explosive alloying (EEA) by boron carbide. EEA of VT6 titanium alloy surface is the plasma alloying formed during the electric explosion of foil with the sample powder of boron carbide. Carbon fibers with weight 140 mg were used as an explosive conductor. Sample powder of boron carbide B4C was placed in the area of explosion on the carbon fibers. It was revealed that EEA of the surface layers of titanium alloy samples VT6 leads to the modification of the layer, thickness of which changes from 10 pm to 50 pm. Heterogeneous distribution of alloying elements was found in the treatment zone by the methods of X-ray microanalysis. A significant difference in their concentration in the identified layers leads to difference in their structural and tribological behaviour. It was revealed that after electro-explosive alloying the microhardness of titanium alloy VT6 significantly increases. Electro-explosive alloying leads to the formation of a structure of submicro- and nano-scale level. It allows strength and tribological properties of the treated surface to be increased.

Quantitative analysis of defect and carbide subsystems evolution in medium-carbon bainitic steel subjected to compressive strain up to 36% was performed by means of transmission electron diffraction microscopy. Dislocation substructure and carbide phase parameters dependence on degree of deformation are identified, possible reasons of staging in their changes are discussed. It is suggested that the reason for bainitic steel softening at high (over 15%) degrees of deformation is activation of deformation microtwinning process.

The objects of the study were polycrystalline copper of M00b grade and commercially pure titanium BT1-0. Microindentation was carried out on the samples of titanium BT1-0 in the initial state, immediately after magnetic field exposure of 0.4 T and after certain time intervals. The defect substructure of cooper samples M00b, subjected to loading to failure in the creep mode under the influence of magnetic field of 0.35 T and without it, was investigated by the methods of electron diffraction microscopy. It was revealed that the effect of magnetic field exposure on commercially pure titanium BT1-0 leads to the decrease in microhardness with the subsequent stabilization during the time that depends on the processing parameters. And the effect of the magnetic field exposure on copper during the process of creeping results in the redistribution of dislocation substructure types. Also, there are changes in quantitative characteristics of dislocation substructures.

Multi-layered coating from immiscible components based on the system Mo-Ni-Cu was formed by the combined method of electro-explosive sputtering and subsequent irradiation by high-intensity pulse electron beam of submillisecond duration of influence on the surface of electrical copper contact (M00 grade of copper). The structure and phase composition studies of the applied coating as well as its mechanical and tribological properties are carried out.

The surface modification of the eutectic silumin with high-intensity pulsed electron beam has been carried out. Multi-cycle fatigue tests were performed and irradiation mode made possible the increase in the silumin fatigue life more than 3.5 times was determined. Studies of the structure of the surface irradiation and surface fatigue fracture of silumin in the initial (unirradiated) state and after modification with intense pulsed electron beam were carried out by methods of scanning electron microscopy. It has been shown, that in mode of partial melting of the irradiation surface the modification process of silicon plates is accompanied by the formation of numerous large micropores along the boundary plate/matrix and microcracks located in the silicon plates. A multi-modal structure (grain size within 30-50 um with silicon particles up to 10 um located on the boundaries) is formed in stable melting mode, as well as subgrain structure in the form of crystallization cells from 100 to 250 um in size). Formation of a multi-modal, multi-phase, submicro- and nanosize structure assisting to a significant increase in the critical length of the crack, the safety coefficient and decrease in step of cracks for loading cycle was the main cause for the increase in silumin fatigue life.

By methods of modern physical materials science the investigations analysis of phase composition, defect substructure, mechanical and tribological properties of Cr-Nb-C-V containing coatings formed in surfacing on martensitic wear resistant steel Hardox 450 were carried out. It was shown that surfacing resulted in the formation of high strength surface layer 6 mm in thinness. This layer had wear resistance 138 times greater than that of the base and friction coefficient 2.5 times less. Having analyzed the deflected mode of the deposited material in conditions of friction, a conclusion is drawn that plastic shear deformation is localized in the surface layer due to the high friction factor, as the result, scratches are formed. The maximum of tangential stress is deflected deep into the material provided that friction factor is low. On the basis of the investigations by methods of X-ray structural analysis and transmission diffraction electron microscopy it was shown that increase strength and tribological properties of surfacing metal were caused by its phase composition and state of defect substructure, namely, availability of interstitial phases (more than 36%) and martensitic type of a-phase structure.

The analysis of structure-phase states modification of silumin subjected to electron beam treatment with the following fatigue loading up to the failure is carried out by methods of transmission electron diffraction microscopy. The tribology and strength properties of silumin surface after electron beam treatment and fatigue tests are studied and hardness decrease, wear coefficient and friction coefficient increase with the growth of cycles number are revealed. The possible reasons of the tribology and strength properties of silumin surface layers decrease are discussed.

The paper presents results of the structural and phase analysis of the surface layer composition in the type R65 rail steel in its original state and after long-term operation. It is shown that long-term operation of rail steel is accompanied by its structural and phase modification at a depth of not less than 2 mm. The structural elements are detected that can be stress concentrators.

The defect substructure of M00b copper samples loaded up to disruption in creep condition both under and without the action of 0.35 T magnetic field is investigated in the paper. Material near the disrupted surface and at certain distances from it received the serious study. It has been ascertained that when copper disrupting without magnetic action on creep process the main type of dislocation substructure is the cellular one irrespectively of the distance to disruption surface. As the result of magnetic field influence on creep process the main type of dislocation substructure is replaced by the stripe-like one. The distinctive quantitative characteristics of dislocation substructures are observed. Moreover, a gradient behavior of the number of stress raisers has been revealed when moving away from disruption surface both in deformation conditions with and without a magnetic field.