Formation Of Microrelief Research Articles

Determining of the effect of reinforcing microrelief guides on the efficiency of folding integrated covers

The object of research is the processes of strengthening the working surfaces of profile folding strips made of stainless steel AISI 347 and carbon steel AISI 1005 using laser formation of microrelief guides. The analytical and experimental studies are based on the technique of laser microrelief formation by pulsed laser effects. The main assumption of the study is that the use of laser microrelief formation could increase the hardness and wear resistance of the folding strips, improving the process of folding integrated covers. Analyzing the effect of different hardening methods on the mechanical properties and wear resistance of the working surfaces of folding strips is necessary to achieve this goal. A methodology for assessing microstructural changes and their impact on the mechanical properties of folding strips during laser hardening has been proposed. It has been shown that the formation of microrelief guides by laser pulse exposure reduces the thermal load on the material, increases the uniformity of hardening and wear resistance. The revealed wear rates calculated for carbon steel AISI 1005 are 0.875, and for stainless steel AISI 347 – 0.345. To improve the accuracy and efficiency of the folding process, a methodology has been devised for calculating the quantitative formation of microrelief guides on the working surface of profile folding strips. This will not only improve the wear resistance and mechanical properties of the strips but also optimize production processes. Differences in the results of hardening for stainless steel AISI 347 and carbon steel AISI 1005 were found: the hardness values for AISI 347 are 3,088–4,904 MPa at a load of 50–350 g with a deviation of 37.1 %, and for AISI 1005 – 2141–1665 MPa with a deviation of 22.3 %

Mathematical modeling in the study of the technological process of formation of anti-erosion microrelief on sloping lands

A theoretical analysis of the technological process of forming an anti-erosion microrelief on the surface of slope fields was carried out, the necessary design parameters of the working parts of the device that influence the technological parameters of the created microrelief were substantiated in order to reduce water and technological erosion.

Ultrasonic surface post-processing of hot isostatic pressed and heat treated superalloy parts manufactured by laser powder bed fusion

• IN 718 alloy parts were fabricated by laser powder bed fusion (L-PBF). • Hot isostatic pressing (HIP) was applied to enhance material density. • Homogenization and aging were applied to provide the required structure and grain size. • Surface improvement was implemented by ultrasonic impact treatment (UIT). • Surface texture, roughness, waviness, structure, and residual stress were studied. Inconel 718 alloy parts were fabricated by the laser powder bed fusion (L-PBF) technique using a multidirectional stripe scanning strategy. Subsequently, the L-PBF-built parts were hot isostatic pressed (HIP), homogenized, and aged. Ultrasonic surface mechanical treatment was applied to modify the surface texture and microstructural layer of the L-PBF-built and heat-treated Inconel 718 alloy parts. Ultrasonic impact treatment (UIT) was implemented using a forcedly rotated multi-pin impact head. The surface texture, roughness, waviness, porosity, microstructure, phase composition, hardness, and residual stresses of the L-PBF-built and thermo-mechanical post-processed specimens were studied and compared. The results revealed that the UIT post-processing leads to work hardening, induces compressive residual stresses, and ∼20% increase in the surface microhardness in the near-surface layer of the heat-treated L-PBF-built 718 alloy parts. The surface roughness and waviness were significantly reduced after UIT, providing a flattened surface microrelief formation.

Investigation of the temperature factor on the formation of a strip surface micro-relief during warm rolling

Kulik T. A. Investigation of the temperature factor on the formation of a strip surface micro-relief during warm rolling
 The temperature is studied as a factor that affects the formation of the micro-relief of the strip, which was rolled with heat. Various schemes for heating the strip to the required temperature are considered. A mathematical model of the temperature distribution over the thickness of the strip and along the length of the deformation zone is obtained. The temperature distribution along the height and length of the deformation zone is not the same. Our studies have shown that the heating scheme is better when the heater is inside the roll. This is better because it gives a smaller temperature spread along the length of the deformation zone. That is, you can better use temperature as a factor. The roughness of the strip during warm rolling is influenced by several factors. If we consider the process with the final tempering, then one of the main factors is temperature. We studied how temperature affects the printability coefficient of the micro-relief from rolls to metal. Experiments were carried out to confirm the results. The experiment consisted in indentation a single indenter into a metal sample. Indenters of various shapes were used, similar to the shape of single micro-protrusions of the real relief of the work rolls. The sample was heated to different temperatures in the drying box, then the depth of its indentation was measured. Experimental studies have shown an almost linear dependence of the penetration depth on temperature, that is, the dependence of the printability coefficient on temperature. This form of dependence was observed for all forms of the indenter, although with different intensity. So, we can confidently say that the temperature factor can be used to control the parameters of the strip roughness that is needed. To do this, at the final stage of the technological chain of rolling, which is temper rolling, you can use the work rolls of the desired micro-relief, and the strip of the desired temperature.

Influence of Abrasive Grains on the Dynamics of Microrelief Formation

Influence of Abrasive Grains on the Dynamics of Microrelief Formation

Synthesis of nano-optical elements for zero-order diffraction 3D imaging

A method is proposed to compute and synthesize a microrelief to produce a new nano-optical element for forming 3D images with full parallax at the zero order of diffraction. The synthesis of nano-optical elements requires the use of multilevel structures. A method is developed for the first time to compute the phase function of such nano-optical elements. Optical security elements that produce the new security feature are synthesized using electron-beam technology. The accuracy of microrelief formation is 10 nm in terms of depth. A sample optical security element is manufactured, which when illuminated by white light, forms a 3D image at the zero order of diffraction. Photos and video of the new 3D visual effect exhibited by real optical elements are presented. The optical elements developed can be replicated using standard equipment employed for manufacturing security holograms. The new optical security feature is easy to control visually, safely protected against counterfeiting, and designed to protect banknotes, documents, ID cards, etc.

The Effect of Surface Processing on the Shear Strength of Cobalt-Chromium Dental Alloy and Ceramics.

Porcelain fused to metal is widespread dental prosthetic restoration. The survival rate of metal-ceramic restorations depends not only on the qualifications of dentists, dental technicians but also on the adhesive strength of ceramics to a metal frame. The goal of the research is to determine the optimal parameters of the surface machining of the metal frame to increase the adhesion of metal to ceramics. Adhesion of cobalt-chromium alloy and ceramics was investigated. A profilometer and a scanning electron microscope were used to analyze the morphology. To estimate the adhesion the shear strength was measured by the method based on ASTM D1002-10. A method of surface microrelief formation of metal samples by plasma-electrolyte treatment has been developed. Regimes for plasma-electrolyte surface treatment were investigated according to current-voltage characteristics and a surface roughness parameter. The samples were subjected to different surface machining techniques such as polishing, milling, sandblasting (so-called traditional methods), and plasma-electrolyte processing. Morphology of the surface for all samples was studied and the difference in microrelief was shown. The roughness and adhesive strength were measured for samples either. As a result, the mode for plasma- electrolytic surface treatment under which the adhesive strength was increased up to 183% (compared with the traditional methods) was found.

Combined Processing of Flat End Surfaces of Electrical Parts

The article shows the relevance and scientific significance in the use of a combined processing method that combines the cutting process and surface plastic deformation, which provides an increase in the efficiency of processing of the basic flat end surfaces of electrical parts made of copper, the study of the patterns of microrelief formation during mechanical processing and plastic deformation of a copper surface. It was found that the use of a combined tool allows you to combine several transitions, which provides an increase in processing productivity by reducing the machine and auxiliary processing time. Replacing the grinding operation of the existing technological process with diamond burnishing can significantly improve the quality of the processed surface.

Динаміка відносних крутильних коливань при формуванні регулярного мікрорельєфу на внутрішніх циліндричних поверхнях

An analysis of modern literature sources to search for mathematical models describing the dynamics of the process of forming a regular microrelief on the inner cylindrical surface of parts, gas transmission equipment operating in severe operating conditions, in order to increase their life. It is established that there are no mathematical models describing this process and the peculiarities of its implementation under the point action of the deforming element on the workpiece surface. The molding movements accompanying the process of forming a regular microrelief on the inner cylindrical surface of the workpiece are considered and the driving forces that accompany this process are analyzed. On the basis of the conducted analysis the mathematical model of dynamic process of formation of a regular microrelief on an internal cylindrical surface of a detail is developed. The peculiarity of this process is that the process of microrelief formation occurs by a concentrated force, the point of application of which in relation to the part is constantly changing in radial and axial directions, and then the mathematical model describing this process will be with a discrete right. It is proposed to model such an action using Dirac delta functions with linear and temporal variables, using the method of regularization of these features, in particular, existing methods of integrating the corresponding nonlinear mathematical models of torsional oscillations of a part. Analytical dependences are obtained, which describe these oscillations in the process of formation of a regular microrelief. Using Maple software, 3D changes in the torsion angle depending on different output values are constructed. The conducted researches will allow to consider torsional fluctuations that is especially actual for long cylindrical details, such as sleeves of hydraulic cylinders, details of drilling mechanisms and others.

Morphology, mineralogical composition and genesis of vertisols in liman Bolshoi (Volgograd region)

The morphological structure of the profiles of two vertisols on microelevations of the gilgai complex of the Bolshoi liman (Svetloyarsk district of the Volgograd region) was studied. Despite the same microrelief position and equal relative heights of microelevations, morphological differences in the profiles at the subtype level were revealed. In one of the profiles, due to the higher humidity, the signs of vertisol genesis were less pronounced. Whereas in the second, more pronounced signs of vertic processes were described – slickensides with 15–30 cm length, smaller slickensides up to 10 cm, wedge-shaped aggregates. The proportion of the clay fraction in the mixed horizons, obtained by the Gorbunov method, was 45– 52%. Analysis of the qualitative mineralogical composition of the clay (<1μm) fractions showed that the smectite phase is represented mainly by disordered and mixed-layered smectite-illite formations. Individual illite belongs to the biotite variety according to the filling of the octahedral layer. Analysis of the ratio of the main mineral phases showed the predominance of illite (53–87%) in all soil samples. In the first pit an increase in the proportion of the smectite component with depth (from 1 to 35%) is noted. In the second pit, there are no regularities in the distribution of mineral phases (fluctuations within 24–37%), which may be associated with the involvement of chocolate clays layers in the profile during soil formation. Mineralogical analysis of chocolate clays (parent rocks) showed their high heterogeneity depending on the depth of the studied layer. No correlation was found between the severity of the signs of vertic processes and the proportion of the swelling component. Illustration of the stages of the formation of the soil cover on the investigated plot of the liman is given. The main reasons that led to the formation of different soils on microelevations are the unevenness of the “squeezing out” of soil blocks upward in the process of microrelief formation in combination with local erosion.

Study of ripple formation on Si surface under Ga ion beam bombardment

The process of microrelief formation on Si (100) surface under 30 keV Ga+ ion beam bombardment with doses 2⋅1017 - 4⋅1018 ion/cm2 at incident angles θ = 0 - 50° was studied. It was found that wave-like structures form on the surface at θ = 25° - 35° and doses 6⋅1017 - 2⋅1018 ion/cm2. The nice ripple formed at θ = 30±2° incident angles and irradiation dose 1018 ion/cm2.

Electroexplosive hafnium coating on titanium implant modified by nitrogen ions and electron beam processing

In the present research a novel method of increasing in mechanical characteristics (wear resistance, friction coefficient, Young's modulus and nanohardness) of titanium implants is proposed. A complex processing was used including electroexplosion spraying of hafnium coating and subsequent electron-beam processing combined with nitriding. Electroexplosion spraying was carried out in the modes ensuring the formation of microrelief on the boundary with titanium substrate. Electron beam processing of hafnium coating surface allowed its smooth surface to be provided and the coating to be nanostructurized. Smooth surface makes the coating a more commercially profitable for selling the medical products and nanostructurization ensures a high level of mechanical and biolodical properties. The obtained coating of Ti-Hf-N system contributes to the increase in wear resistance by the factor of 17.4 and simultaneous increase in friction coefficient by 7%. The coating also ensures the increase in nanohardness by the factor of 2.05 and the increase in the Young modulus by 13% in comparison with Ti-6Al-4V alloy. Nitriding allowed the strengthening of hafnium coating by nitrides. In the coating 40–50 μm in thickness hafnium is distributed homogeneously and is presented in the phases of HfN, Hf and HfTiN2. The comparison of the phases being formed in the coating and the structural components of coatings' surface depending on processing mode is made. After combined processing the surface of the coating is presented by three different structural components. The proliferative activity of fibroblasts and antimicrobial activity were studied as biological properties of the coating in the present research. The structure of the coating is studied by the methods of modern physical materials science. The complex analysis carried out enables one to recommend the coating for subsequent tests on experimental animals (rabbits) and further commercial production of strengthened titanium implants. To study osteointegration the samples of the experimental implants with bioinert coatings obtained in the present research are to be introduced into rabbits' osseous tissue in future.

Optimization of the parameters of a partially regular microrelief by vibration rolling method

Experience of operating machines shows that their quality depends on the nature of the contact of mating parts. The irregular nature of the surface microrelief, which is due to traditional treatment methods used, arises difficulties in solving three main problems of microgeometry optimization: reliable, theoretically substantiated normalization, technological support, accurate measurement and control. This determined the direction in solving the problem of increasing the accuracy and reliability of the surface quality normalization, that is the microrelief normalization. At present, there are a large number of technological methods for surface treatment aimed to form a regular microrelief on it. One of the most common and studied methods for the regular microrelief formation is the vibration rolling method based on thin plastic deformation of the surface metal layers and a complex relative displacement of the treated surface and the deforming element. Significant progress in the surface quality normalization was achieved after the introduction of GOST 24773-81, the standard for regular microreliefs. For example, the nomenclature of parameters and characteristics of partially regular microreliefs includes the relative area occupied by regular inhomogeneities FH. FH is a value expressed as a percentage of the area occupied by regular inhomogeneities to the area of the treated surface. If FH is determined for the 2A·Sk area within the boundaries of a microrelief element at different axial steps of regular inhomogeneities, the microgeometry of a partially regular microrelief can be described ambiguously. To avoid this, it is necessary to consider the multiplicity of the ratio of the amplitude A to the axial step So.

Dynamics of regular microrelief formation on internal cylindric surfaces

An analysis of modern literature sources to search for mathematical models describing the dynamics of the process of forming a regular microrelief on the inner cylindrical surface of parts, gas transmission equipment operating in severe operating conditions, in order to increase their life. It is established that there are no mathematical models describing this process and the peculiarities of its implementation under the point action of the deforming element on the workpiece surface. The molding movements accompanying the process of forming a regular microrelief on the inner cylindrical surface of the workpiece are considered and the driving forces that accompany this process are analyzed. A mathematical model of dynamic process of regular microrelief formation on internal cylindric surface of the part has been developed. The process of formation is a unique one as it occurs due to the concentrated force whose point of application varies in radial and axial directions relative to the part. Thus, the action has been described by the mathematical model with discrete right-hand side. This action is proposed to be simulated by Dirac delta functions of linear and time variables using the method of regularization of the specific features under discussion. These peculiar features have been described by the conventional methods of integrating of correspondent nonlinear mathematical models of longitudinal and lateral vibrations of the part. The analytical dependencies describing these vibrations have been obtained based on the initial data. Using Maple software, 3D changes in the torsion angle depending on different output values are constructed. The conducted researches will allow to consider torsional fluctuations that is especially actual for long cylindrical details, such as sleeves of hydraulic cylinders, details of drilling mechanisms and others.

Influence of optical forces induced by paraxial vortex Gaussian beams on the formation of a microrelief on carbazole-containing azopolymer films.

The paper discusses photoinduced microrelief formation in a film of an azopolymer. A theoretical study of the effect of laser beam polarization on the balance of optical forces acting under the direct action of paraxial Gaussian beams on the irradiated substance was made. We show that taking into account the gradient and scattering components of the force does not allow us to correctly describe the shape of the microasperities obtained on a carbazole-containing azopolymer. An approximation function is presented that describes the dependence of the microasperities' shapes on the non-gradient component of the optical force of laser radiation in the absence and presence of a vortex phase. A comparative analysis of the approximation results and experimentally obtained microreliefs was carried out.

Kinematics of the grinding process

The possibility of chip removal is governed by the section thickness, properties of metal under deformation speed, geometric parameters of cutting edges of the wheel. Randomized geometry and arbitrary location of cutting edges on the work surface of grinding wheel allow the application of probabilistic-statistical approach for description of regularities of the grinding process. The main characteristics of formation of microrelief of work surface of the wheel depend on the law of difference in altitude of cutting edges and corner radiuses of their tops. The studies on the kinematics of interaction between a grinding wheel and a machined surface during face grinding showed that overlapping of scratches across the width occurs at a smaller depth. Cutting depth of a grinding wheel does not depend on the value of longitudinal and cross feed, but it is determined by the law of grain distribution in the volume of abrasive layer as well as the shape of the tops of abrasive grains. It is established that abrasive grains located in a work surface layer to the cutting depth are in the most unfavorable conditions due to their small amount and highest difference in altitude. It leads to an increase in the size of the chip, occurrence of the highest cutting forces and wear of grains.

Features of microrelief formation during laser treatment of Cu-Cr-Zr alloy surface for diffusion welding

The effect of UV laser pulses of nanosecond duration on surface of Cu-Cr-Zr alloy samples was investigated. Noticeable changes in the morphology of the surface layer after irradiation were found at pre-threshold values of the energy density of ∼ 0.2 – 0.8 J/cm2. Changes are traces of thermoplastic deformation resulting from influence of a concentrated energy flow and appears in irregular elevation of the irradiated surface area of the sample by up to 1 μm and in some cases – more. A developed metal surface, deformation of the crystal structure of the surface layer can support the diffusion process during diffusion welding. For energy densities of the order of 1 J/cm2 or more, optical breakdown with the formation of a crater on the metal surface occurred. The mechanical impulse of a laser plasma when exposed to a metal surface prevents the thermomechanical expansion of the material, and the effect of raising the surface of the samples was not observed.

Spatial distribution of single specie dominant forests of Erythrina fusca Lour. at the Taiamã Ecological Station, Pantanal, Mato Grosso, Brazil

The Pantanal biome has a great variety of habitats where plant species are distributed according to their particularities. This study aimed at evaluating the spatial distribution of arboreal/shrub vegetation in areas of single specie dominance Erythrina fusca forests. An aggregation test (K(t)) for E. fusca and spatial dependence tests (K(12)) between E. fusca and Calophyllum brasiliense, as well as Alchornea discolor and Banara arguta were performed. The correlation of the distance from the beginning of the plots (riverbank) to the abundance of individuals was tested, and finally, the Kernel density was estimated. We found that E. fusca is randomly distributed throughout the area, that the distribution of C. brasiliense and A. discolor is dependent on E. fusca, and that of B. arguta is not. The correlation analysis pointed to a decrease in the abundance of the community from the riverbank to the interior of the island, with a smaller reduction in the population of E. fusca. The density was higher in the regions close to the river. In addition, sites with a high concentration of individuals close to the elevations created by the roots of E. fusca were verified. The distribution of individuals was related to the flood pulse and the adaptive processes of plant establishment, where the flooding selects the species most tolerant to this type of environment, and the formation of higher microrelief in the landscape can increase the dispersion of the species. This points out that any disturbance that may occur in the flood pulse will change the environmental balance.

Features of fused silica ablation by laser induced carbon microplasma

The features of surface structuring on the transparent material by laser-induced microplasma were studied and the intensity of its microplasma was measured. The formation of micro-relief by a series of nanosecond pulsed laser induced carbon microplasma in confinement mode on the surface of fused silica were investigated and the measured intensity was compared with the features of micro-relief. The dependence of depth of formed relief and track on the laser regime was determined. It is shown that the mechanism of microstructure formation is dependent on multifactor and associated with the ablation on the surface of fused silica by the microplasma, which exists quite long time after the pulses.

Kinematics of cutting process while honing holes with a hone with variable geometry of sticks

The article considers the process of kinematics in the formation of the grid of traces taking into account the influence on microrelief of the formed surface. Schemes of interaction of the machined surface with diamond-abrasive sticks, which are positioned at different angles and their influence on the formation of the microrelief of the machined holes have been given. The calculation scheme of positioning diamond-abrasive sticks at different angles is presented. On this basis, mathematical models of density of the formed grid of traces were obtained. The study of the influence of the inclination angle of diamond-abrasive sticks on the formation of the macrorelief of the machined hole is also presented. The influence of transfer of peculiar geometrical deviations of honing heads on the machined surface is defined.