Pub Date : 2023-10-16DOI: 10.15588/1607-6885-2023-3-1
V. Greshta, M. Brykov, V. Shalomeev, D. Pavlenko, D. Tkach, V. Efremenko, I. Petryshynets
Purpose of this work was to determine the characteristics of coatings formed on magnesium alloys during the process of micro-arc oxidation (MAO) in an electrolyte with minimal content of basic solution components. Additionally, the study aims to identify research directions that can ensure controlled solubility of magnesium alloys with MAO coatings in a corrosive and active environment.
Research methods. The study was performed on samples of MЛ5 alloy. The MAO was conducted using an alternating current of 380 V and 50 Hz, along with a battery of capacitors with adjustable capacity. The electrolyte used was a combination of potassium hydroxide and sodium liquid glass. Corrosion tests of the treated samples were conducted in a 3 % aqueous NaCl solution. The surface of the samples after MAO was examined using optical and scanning electron microscopy.
Results. The results of research in the field of MAO of magnesium alloys are considered. It is shown that the use of MAO coatings is one of the promising directions for developing methods to control the dissolution rate of magnesium alloy products. The concentration of reagents in the electrolyte and the processing time were minimized. It was found that it is advisable to complete the treatment before the phase of intense sparking. The initiation of the sparking process leads to the damage of the barrier layer by microarc discharges, which reduces the corrosion resistance of the coating.
Scientific novelty. It was found that the degree of corrosion damage was minimal for the sample treated for 30 s. The obtained result can be explained by the termination of the MАO process at the moment when a dense coating has already formed at the first stage of the process, but the second stage with the formation of micro-arc discharges, which damage the already formed oxide layer, has not yet begun.
Practical value. The results of the study will serve as a basis for further work aimed at creating magnesium alloy products with a controlled dissolution time in a corrosive environment. This is especially relevant for medical products, namely metal fixators for osteosynthesis with a controlled rate of biological resorption.
{"title":"FEATURES OF MICROARC OXIDATION OF MAGNESIUM ALLOYS AND CORROSION DESTRUCTION OF THE RESULTING COATINGS","authors":"V. Greshta, M. Brykov, V. Shalomeev, D. Pavlenko, D. Tkach, V. Efremenko, I. Petryshynets","doi":"10.15588/1607-6885-2023-3-1","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-1","url":null,"abstract":"Purpose of this work was to determine the characteristics of coatings formed on magnesium alloys during the process of micro-arc oxidation (MAO) in an electrolyte with minimal content of basic solution components. Additionally, the study aims to identify research directions that can ensure controlled solubility of magnesium alloys with MAO coatings in a corrosive and active environment.
 Research methods. The study was performed on samples of MЛ5 alloy. The MAO was conducted using an alternating current of 380 V and 50 Hz, along with a battery of capacitors with adjustable capacity. The electrolyte used was a combination of potassium hydroxide and sodium liquid glass. Corrosion tests of the treated samples were conducted in a 3 % aqueous NaCl solution. The surface of the samples after MAO was examined using optical and scanning electron microscopy.
 Results. The results of research in the field of MAO of magnesium alloys are considered. It is shown that the use of MAO coatings is one of the promising directions for developing methods to control the dissolution rate of magnesium alloy products. The concentration of reagents in the electrolyte and the processing time were minimized. It was found that it is advisable to complete the treatment before the phase of intense sparking. The initiation of the sparking process leads to the damage of the barrier layer by microarc discharges, which reduces the corrosion resistance of the coating.
 Scientific novelty. It was found that the degree of corrosion damage was minimal for the sample treated for 30 s. The obtained result can be explained by the termination of the MАO process at the moment when a dense coating has already formed at the first stage of the process, but the second stage with the formation of micro-arc discharges, which damage the already formed oxide layer, has not yet begun.
 Practical value. The results of the study will serve as a basis for further work aimed at creating magnesium alloy products with a controlled dissolution time in a corrosive environment. This is especially relevant for medical products, namely metal fixators for osteosynthesis with a controlled rate of biological resorption.","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136112228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-16DOI: 10.15588/1607-6885-2023-3-7
A. Dzhus, O. Narivskyi, S. Byelikov, S. Subbotin, T. Pulina, S. Leoshchenko
Purpose. The aim of the study is to develop mathematical models that describe the dependences of critical pitting temperatures of 06ХН28МДТ alloy (analogous to AISI904L steel) in model circulating waters with pH 4...8 and chloride concentration from 350 to 600 mg/L. Research methods. The developed mathematical models are based on multivariate linear regressions of the first order and multivariate quadratic regressions with a combination of features. Results. It has been established that the critical pitting temperatures of the 06ХН28МДТ alloy increase with increasing pH of model circulating waters, Ni, Mo content, volume of titanium nitrides, and decreasing chloride concentration in the medium, Cr content within the standard, and average austenite grain diameter. Scientific novelty. Based on the established dependencies between the critical pitting temperatures of the 06ХН28МДТ alloy and its chemical composition within the standard and structural heterogeneity, the mechanisms of their influence on the pitting resistance of this structural material in recycled industrial waters were developed. It was found that the size of inclusions of titanium nitrides and oxysulfides in the alloy does not affect the probability of the formation and growth of stable pitting in their vicinity in chloride-containing media. Practical value. To apply the developed mathematical models to the selection of the most resistant to pitting in recycled industrial waters of 06ХН28МДТ alloy melts and to predict their pitting during the use of heat exchangers have been offered.
{"title":"MATHEMATICAL MODELING OF PITTING RESISTANCE IN 06XH28МДТ ALLO-HEAT EXCHANGERS EXPOSED TO CIRCULATING WATERS","authors":"A. Dzhus, O. Narivskyi, S. Byelikov, S. Subbotin, T. Pulina, S. Leoshchenko","doi":"10.15588/1607-6885-2023-3-7","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-7","url":null,"abstract":"Purpose. The aim of the study is to develop mathematical models that describe the dependences of critical pitting temperatures of 06ХН28МДТ alloy (analogous to AISI904L steel) in model circulating waters with pH 4...8 and chloride concentration from 350 to 600 mg/L. Research methods. The developed mathematical models are based on multivariate linear regressions of the first order and multivariate quadratic regressions with a combination of features. Results. It has been established that the critical pitting temperatures of the 06ХН28МДТ alloy increase with increasing pH of model circulating waters, Ni, Mo content, volume of titanium nitrides, and decreasing chloride concentration in the medium, Cr content within the standard, and average austenite grain diameter. Scientific novelty. Based on the established dependencies between the critical pitting temperatures of the 06ХН28МДТ alloy and its chemical composition within the standard and structural heterogeneity, the mechanisms of their influence on the pitting resistance of this structural material in recycled industrial waters were developed. It was found that the size of inclusions of titanium nitrides and oxysulfides in the alloy does not affect the probability of the formation and growth of stable pitting in their vicinity in chloride-containing media. Practical value. To apply the developed mathematical models to the selection of the most resistant to pitting in recycled industrial waters of 06ХН28МДТ alloy melts and to predict their pitting during the use of heat exchangers have been offered.","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136112397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-16DOI: 10.15588/1607-6885-2023-3-10
T. Levytska, I. Pozhuieva, O. Mytryashkin, O. Manzhos
Purpose. Study of the stress-strain state and fatigue life of the local zone of the compartment structure, namely, the radial transition between the wall thicknesses from the regular zone to the place of thickening in the connection zone with the reinforcement element. The main task of this work is to estimate the level of stress in the zone of the radial transition using the numerical solution of the problem, for the further assessment of the resource of the structure.
Research methods. Construction of a local model and numerical calculations of the stress-strain state of the considered structure using PATRAN/NASTRAN software complexes. Using the Mesh Seed tool to mark the position of nodes on the edges of surfaces. In addition to flat elements, bar elements were used in the model to simulate rivets. For the numerical solution of the presented problem, the nonlinear solver 106 - Nonlinear Static was used.
Results. A numerical calculation of the stress-strain state of the nose strut of the aircraft landing gear with a radial transition in thickness during local modeling was carried out. Visualization of linear displacement and fields of normal stresses, as well as graphs of normal stresses on the lower and upper surface of the wall, and the dependence of the values of normal stresses in the radial transition zone were obtained. The deflection of the plate between the reinforcement element is plotted and the maximum deflection in the middle of the span is obtained.
Scientific novelty. Application of the method of calculating the stress-strain state of complex structures of aviation equipment elements using computer software complexes in the conditions of modern development of aviation science and technology.
Practical value. The obtained calculations made it possible to estimate the resource of the local area of the structure - the radius transition between different wall thicknesses. The results of the analysis and the method of numerical calculation of the stress-strain state of the considered model can be used for further assessment of the resource and static strength of the structure of the aircraft landing gear compartment.
{"title":"CALCULATION OF THE STRESS-STRAIN STATE OF THE NOSE STAND OF AN AIRCRAFT LANDING GEAR WITH A RADIUS TRANSITION BY THICKNESS WHEN BUILDING A LOCAL MODEL","authors":"T. Levytska, I. Pozhuieva, O. Mytryashkin, O. Manzhos","doi":"10.15588/1607-6885-2023-3-10","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-10","url":null,"abstract":"Purpose. Study of the stress-strain state and fatigue life of the local zone of the compartment structure, namely, the radial transition between the wall thicknesses from the regular zone to the place of thickening in the connection zone with the reinforcement element. The main task of this work is to estimate the level of stress in the zone of the radial transition using the numerical solution of the problem, for the further assessment of the resource of the structure.
 Research methods. Construction of a local model and numerical calculations of the stress-strain state of the considered structure using PATRAN/NASTRAN software complexes. Using the Mesh Seed tool to mark the position of nodes on the edges of surfaces. In addition to flat elements, bar elements were used in the model to simulate rivets. For the numerical solution of the presented problem, the nonlinear solver 106 - Nonlinear Static was used.
 Results. A numerical calculation of the stress-strain state of the nose strut of the aircraft landing gear with a radial transition in thickness during local modeling was carried out. Visualization of linear displacement and fields of normal stresses, as well as graphs of normal stresses on the lower and upper surface of the wall, and the dependence of the values of normal stresses in the radial transition zone were obtained. The deflection of the plate between the reinforcement element is plotted and the maximum deflection in the middle of the span is obtained.
 Scientific novelty. Application of the method of calculating the stress-strain state of complex structures of aviation equipment elements using computer software complexes in the conditions of modern development of aviation science and technology.
 Practical value. The obtained calculations made it possible to estimate the resource of the local area of the structure - the radius transition between different wall thicknesses. The results of the analysis and the method of numerical calculation of the stress-strain state of the considered model can be used for further assessment of the resource and static strength of the structure of the aircraft landing gear compartment.","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136112400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-11DOI: 10.15588/1607-6885-2023-3-9
V. Shevchenko, S. Ryagin, D. Artsybasheva
Purpose. Increase of the competitiveness is the important scientific and practical task in machine building. The press is the stationary equipment, but reduction of weight of its elements, in particular – columns, reduces manufacturing cost, facilitates transportation and installation, therefore assists in increase of product attraction at market relations. The purpose is to reduce press column weight without complication of technological process of its manufacturing and without additional expenses for a concrete one-columned press by means of structure optimization.
Research methods. The mathematical model has been developed on the basis of formula of combined strength of materials. The pure bending with tension results from operation of one-columned press. Multicriterion optimization has been carried out by means of computer facilities. Calculation was carried out by means of the program written in language Basic.
Results. The press П6330 with box-shaped cross-section has been chosen as a base variant. The optimal geometrical dimensions have been determined for the offered T-shaped welded cross-section of a column. Technological process of manufacturing of such column is simplified.
Scientific novelty. The T-shaped welded column cross-section has been offered for the purpose of modernization. Such cross-section scheme is more perspective and technological. The following 3 criteria have been chosen at multicriterion optimization carrying out: equal strength with the base variant, the greatest uniformity of distribution of stress by cross-section, the least area of cross-section. The main geometrical dimensions of cross-section have been chosen as 4 variable parameters. It was considered, that thickness of metal sheet is discrete and standard.
Practical value. Multicriterion optimization that had been carried out provides reduction of column weight approximately by 45 % for the modernized variant without increase in dimensions of cross-section. It gives the opportunity to reduce considerably the column manufacturing cost in comparison with a base variant, and also to facilitate transportation and installation of the press.
{"title":"MULTICRITERION OPTIMIZATION OF PRESS COLUMN CROSSSECTION","authors":"V. Shevchenko, S. Ryagin, D. Artsybasheva","doi":"10.15588/1607-6885-2023-3-9","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-9","url":null,"abstract":"Purpose. Increase of the competitiveness is the important scientific and practical task in machine building. The press is the stationary equipment, but reduction of weight of its elements, in particular – columns, reduces manufacturing cost, facilitates transportation and installation, therefore assists in increase of product attraction at market relations. The purpose is to reduce press column weight without complication of technological process of its manufacturing and without additional expenses for a concrete one-columned press by means of structure optimization.
 Research methods. The mathematical model has been developed on the basis of formula of combined strength of materials. The pure bending with tension results from operation of one-columned press. Multicriterion optimization has been carried out by means of computer facilities. Calculation was carried out by means of the program written in language Basic.
 Results. The press П6330 with box-shaped cross-section has been chosen as a base variant. The optimal geometrical dimensions have been determined for the offered T-shaped welded cross-section of a column. Technological process of manufacturing of such column is simplified.
 Scientific novelty. The T-shaped welded column cross-section has been offered for the purpose of modernization. Such cross-section scheme is more perspective and technological. The following 3 criteria have been chosen at multicriterion optimization carrying out: equal strength with the base variant, the greatest uniformity of distribution of stress by cross-section, the least area of cross-section. The main geometrical dimensions of cross-section have been chosen as 4 variable parameters. It was considered, that thickness of metal sheet is discrete and standard.
 Practical value. Multicriterion optimization that had been carried out provides reduction of column weight approximately by 45 % for the modernized variant without increase in dimensions of cross-section. It gives the opportunity to reduce considerably the column manufacturing cost in comparison with a base variant, and also to facilitate transportation and installation of the press.","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136253776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-11DOI: 10.15588/1607-6885-2023-3-13
V. Pleskach, I. Akimov
{"title":"DESTRUCTION AND INCREASE OF STRENGTH OF POWDER PRODUCTS","authors":"V. Pleskach, I. Akimov","doi":"10.15588/1607-6885-2023-3-13","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-13","url":null,"abstract":"","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136253778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-11DOI: 10.15588/1607-6885-2023-3-6
Е. Parahnevich
Purpose. As a result of the study, it is necessary to determine the factors that influence the chemical composition of the fusion zone and non-metallic inclusions during electroslag surfacing, which is used in the restoration of railway transport parts, namely electric locomotives of the ЧС-4, ЧС-6, ЧС-8, etc. brands. Research methods. The chemical composition of non-metallic inclusions was studied using the CAMECA X-ray spectroscopic microanalysis unit and the "SUPRA 40 WDS" scanning electron microscope manufactured by Carl Zeiss (Germany). The measurement error is no more than 1 %. The nature of non-metallic inclusions (microstructure, morphology and topography) was studied by the petrographic method using a complex methodology. Samples for research were cut from the metal of the experimental deposits in such a way that the fusion zone was located in the middle of the sample. Chemical etching of the metal with a 4% solution of sulfuric acid was carried out to identify the fusion zone. Results. As a result of the study of the chemical and mineralogical nature of non-metallic inclusions, it is shown that in the base metal (Ст.3 steel) when approaching the fusion zone, the number and size of non-metallic inclusions decrease, as well as their shape, microstructure and composition change. There are practically no non-metallic inclusions in the heating zone (immediately near the fusion zone). Scientific novelty. It is shown that the content of elements from the base metal to the deposited metal practically does not change, with the exception of chromium, the content of which gradually increases from Ст.3 steel to 12X13 steel in the fusion zone. Practical value. The results of the work make it possible to explain the effect of electroslag restoration of electric locomotive parts on the quality of the fusion zone and to explain the mechanism of structure defects and possible types of non-metallic inclusions as a result of surfacing.
{"title":"THE INFLUENCE ELECTROSLAG HARD-FACING ON THE CHEMICAL COMPOUND OF NONMETALLIC INCLUSIONS AND FUSION ZONE","authors":"Е. Parahnevich","doi":"10.15588/1607-6885-2023-3-6","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-6","url":null,"abstract":"Purpose. As a result of the study, it is necessary to determine the factors that influence the chemical composition of the fusion zone and non-metallic inclusions during electroslag surfacing, which is used in the restoration of railway transport parts, namely electric locomotives of the ЧС-4, ЧС-6, ЧС-8, etc. brands. \u0000Research methods. The chemical composition of non-metallic inclusions was studied using the CAMECA X-ray spectroscopic microanalysis unit and the \"SUPRA 40 WDS\" scanning electron microscope manufactured by Carl Zeiss (Germany). The measurement error is no more than 1 %. The nature of non-metallic inclusions (microstructure, morphology and topography) was studied by the petrographic method using a complex methodology. Samples for research were cut from the metal of the experimental deposits in such a way that the fusion zone was located in the middle of the sample. Chemical etching of the metal with a 4% solution of sulfuric acid was carried out to identify the fusion zone. \u0000Results. As a result of the study of the chemical and mineralogical nature of non-metallic inclusions, it is shown that in the base metal (Ст.3 steel) when approaching the fusion zone, the number and size of non-metallic inclusions decrease, as well as their shape, microstructure and composition change. There are practically no non-metallic inclusions in the heating zone (immediately near the fusion zone). \u0000Scientific novelty. It is shown that the content of elements from the base metal to the deposited metal practically does not change, with the exception of chromium, the content of which gradually increases from Ст.3 steel to 12X13 steel in the fusion zone. \u0000Practical value. The results of the work make it possible to explain the effect of electroslag restoration of electric locomotive parts on the quality of the fusion zone and to explain the mechanism of structure defects and possible types of non-metallic inclusions as a result of surfacing.","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136252946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-11DOI: 10.15588/1607-6885-2023-3-12
О. Nesterov, V. Ruban, V. Kuzmenko
IMPLEMENTATION OF MODERN NITRIDING TECHNOLOGIESTOIMPROVE WORKING CONDITIONS AND ENHANCE THE ENVIRONMENTAL FACILITIES FOR PROCESSES
实施现代氮化技术，改善工作条件，提高工艺环境设施
{"title":"IMPLEMENTATION OF MODERN NITRIDING TECHNOLOGIESTO IMPROVE WORKING CONDITIONS AND ENHANCE THE ENVIRONMENTAL FACILITIES FOR PROCESSES","authors":"О. Nesterov, V. Ruban, V. Kuzmenko","doi":"10.15588/1607-6885-2023-3-12","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-12","url":null,"abstract":"IMPLEMENTATION OF MODERN NITRIDING TECHNOLOGIESTOIMPROVE WORKING CONDITIONS AND ENHANCE THE ENVIRONMENTAL FACILITIES FOR PROCESSES","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136252947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-11DOI: 10.15588/1607-6885-2023-3-8
N. Antonenko, I. Tkachenko
Purpose. It consists in obtaining an analytical expression for calculating the temperature at the points of a multilayer plate under the condition of imperfect thermal contact between its layers, presenting obtained formulas in a for convenient for numerical implementation and investigating the influence of the thermal resistance coefficient on the temperature distribution in the plate layers.
Research methods. To solve the given problem, the method of integral transformations (double integral Fourier transform) and the method of compliance functions were used.
Results. In the form of improper Fourier integrals the formulas for calculating the temperature at any point of the multilayer plate were obtained. Numerical results for three-layer plates were conducted, on the outer surfaces of which a thermal load that uniformly distributed over the square (the intensity of the thermal loads on the lower boundary is ten times more than on the upper one) was given. The graphs that illustrate the influence of the thermal resistance coefficients on the temperature distribution at the points of the lower boundaries of the first and second layers were obtained. It was shown that the raise of the coefficients of thermal resistance leads to decreasing of the temperature at the points of these boundaries. The proposed method can be used to determine the temperature at the points of the plates with any finite number of layers.
Scientific novelty. For the first time, the three-dimensional problem of thermal conductivity for the layered plate with imperfect thermal contact between its layers was solved by the method of compliance functions. Previously, only two-dimensional and axisymmetric problems of this type were solved by this method.
Practical value. The obtained results can be used as the test ones when performing analogous calculations by other methods. Based on the results of numerical calculations in designing layered structures, it is possible to select their elements with the necessary thermal characteristics.
{"title":"THREE-DIMENSIONAL THERMAL CONDUCTIVITY PROBLEM FOR A MULTILAYER PLATE WITH IMPERFECT THERMAL CONTACT BETWEEN ITS LAYERS","authors":"N. Antonenko, I. Tkachenko","doi":"10.15588/1607-6885-2023-3-8","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-8","url":null,"abstract":"Purpose. It consists in obtaining an analytical expression for calculating the temperature at the points of a multilayer plate under the condition of imperfect thermal contact between its layers, presenting obtained formulas in a for convenient for numerical implementation and investigating the influence of the thermal resistance coefficient on the temperature distribution in the plate layers.
 Research methods. To solve the given problem, the method of integral transformations (double integral Fourier transform) and the method of compliance functions were used.
 Results. In the form of improper Fourier integrals the formulas for calculating the temperature at any point of the multilayer plate were obtained. Numerical results for three-layer plates were conducted, on the outer surfaces of which a thermal load that uniformly distributed over the square (the intensity of the thermal loads on the lower boundary is ten times more than on the upper one) was given. The graphs that illustrate the influence of the thermal resistance coefficients on the temperature distribution at the points of the lower boundaries of the first and second layers were obtained. It was shown that the raise of the coefficients of thermal resistance leads to decreasing of the temperature at the points of these boundaries. The proposed method can be used to determine the temperature at the points of the plates with any finite number of layers.
 Scientific novelty. For the first time, the three-dimensional problem of thermal conductivity for the layered plate with imperfect thermal contact between its layers was solved by the method of compliance functions. Previously, only two-dimensional and axisymmetric problems of this type were solved by this method.
 Practical value. The obtained results can be used as the test ones when performing analogous calculations by other methods. Based on the results of numerical calculations in designing layered structures, it is possible to select their elements with the necessary thermal characteristics.","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136253947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-11DOI: 10.15588/1607-6885-2023-3-4
V. Greshta, A. Yershov, V. Hrabovskyi, V. Vinichenko, S. Seidametov
Purpose. It is based on the method of determining the physical and mechanical characteristics and cohesive strength of the plasma coating.
Research methods. Experimental research methods of plasma coating specimens and mathematical methods of the theory of strength of materials. Received results. The study of the mechanical properties of the ПРНХ15СР2 plasma coating during the bending test was carried out. Values of forces and moments of elastic forces during bending depending on the deformation of the plasma coating sample was determined. The dependence of the destructive stress on the relative deformation of the coating was calculated. The modulus of elasticity and strength for the outer and inner surfaces of the coating are determined.
Scientific novelty. It is shown that when determining the mechanical characteristics of the coating bonded to the base, a systematic error occurs due to the uncertainty of the internal stress in the coating. Therefore, for measurement, it is proposed to use samples peeled from the base, which are practically devoid of internal stress. For the inner surface of the coating, the modulus of elasticity and the destructive stress are rather higher than for the outer surface. The detected difference is associated with the presence of a temperature gradient during coating application and the distribution of residual stresses over the thickness of the coating. The gradient of residual thermal stresses and the maximum permissible temperature in the process of the coating deposition are determined.
Practical value. The obtained results are of practical value for determining the conditions of guaranteed preservation of the integrity of the coating in the presence of residual stresses and calculating its maximum thickness on the base surface. It is shown that when the power of the plasmatron is reduced, the thermal stress gradient and the maximum stress on the coating surface decrease. Therefore, it is recommended to use a wire instead of a powder plasmatron, which twice reduces thermal stresses by half.
{"title":"PHYSICAL-MECHANICAL CHARACTERISTICS AND THERMAL STRESS OF PLASMA COVERING","authors":"V. Greshta, A. Yershov, V. Hrabovskyi, V. Vinichenko, S. Seidametov","doi":"10.15588/1607-6885-2023-3-4","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-4","url":null,"abstract":"Purpose. It is based on the method of determining the physical and mechanical characteristics and cohesive strength of the plasma coating.
 Research methods. Experimental research methods of plasma coating specimens and mathematical methods of the theory of strength of materials. Received results. The study of the mechanical properties of the ПРНХ15СР2 plasma coating during the bending test was carried out. Values of forces and moments of elastic forces during bending depending on the deformation of the plasma coating sample was determined. The dependence of the destructive stress on the relative deformation of the coating was calculated. The modulus of elasticity and strength for the outer and inner surfaces of the coating are determined.
 Scientific novelty. It is shown that when determining the mechanical characteristics of the coating bonded to the base, a systematic error occurs due to the uncertainty of the internal stress in the coating. Therefore, for measurement, it is proposed to use samples peeled from the base, which are practically devoid of internal stress. For the inner surface of the coating, the modulus of elasticity and the destructive stress are rather higher than for the outer surface. The detected difference is associated with the presence of a temperature gradient during coating application and the distribution of residual stresses over the thickness of the coating. The gradient of residual thermal stresses and the maximum permissible temperature in the process of the coating deposition are determined.
 Practical value. The obtained results are of practical value for determining the conditions of guaranteed preservation of the integrity of the coating in the presence of residual stresses and calculating its maximum thickness on the base surface. It is shown that when the power of the plasmatron is reduced, the thermal stress gradient and the maximum stress on the coating surface decrease. Therefore, it is recommended to use a wire instead of a powder plasmatron, which twice reduces thermal stresses by half.","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136253777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-11DOI: 10.15588/1607-6885-2023-3-5
O. Omelchenko, N. Shaleva, V. Yefanov
Purpose. Improvement of the technological modes of smelting sputtering cathodes based on nickel of the Ni-Cr-Al-Y system in order to improve their quality, namely, to reduce the total number of defects in the form of discontinuities, pores, non-melts and increase the homogeneity of the structure and chemical composition and application of the protective atmosphere of inert gases, the most widespread of which are helium and argon.
Research methods. The equipment was improved, in particular, the vacuum-arc installation was equipped with a ramp and a helium cylinder. Test samples in the form of “washers” (diameter 127 mm and thickness 40 mm) were obtained, which were used to study the microstructure and chemical composition. Remelting modes have been worked out. The study of the chemical composition was carried out using a multipurpose scanning electron microscope REM 106I, equipped with a microanalysis system.
Results. Based on the results of studies of the influence of the gas mixture concentration on the structure and composition of the cathodes, technological modes of melting were established, which made it possible to improve the quality indicators and economic indicators of the investigated cathodes. This will have a positive effect on the number of cathode failures, the performance of coated parts and the life of aircraft engines in general.
Scientific novelty. The dependence of the influence of the concentration of the mixture of gases (argon-helium) was determined, which made it possible to obtain the optimal ratio of protective gases. With a gas ratio of 70/30 %, the highest quality cathodes were obtained, which were used for further research.
Practical value. Quality of coating sputtering is determined by regimes of sputtering and quality of cathode itself. One of applied methods is by-layered melting of cathodes in copper water-cooled crystallizer using electrodes that are melted or non-melted. Optimal ratio of protective gases for receiving qualitative cathodes is determined.
{"title":"DETERMINATION OF THE INFLUENCE OF THE MIXTURE OF GASES ON IMPROVING THE QUALITY OF CATHODES FOR ION-PLASMA SPUTTERING","authors":"O. Omelchenko, N. Shaleva, V. Yefanov","doi":"10.15588/1607-6885-2023-3-5","DOIUrl":"https://doi.org/10.15588/1607-6885-2023-3-5","url":null,"abstract":"Purpose. Improvement of the technological modes of smelting sputtering cathodes based on nickel of the Ni-Cr-Al-Y system in order to improve their quality, namely, to reduce the total number of defects in the form of discontinuities, pores, non-melts and increase the homogeneity of the structure and chemical composition and application of the protective atmosphere of inert gases, the most widespread of which are helium and argon.
 Research methods. The equipment was improved, in particular, the vacuum-arc installation was equipped with a ramp and a helium cylinder. Test samples in the form of “washers” (diameter 127 mm and thickness 40 mm) were obtained, which were used to study the microstructure and chemical composition. Remelting modes have been worked out. The study of the chemical composition was carried out using a multipurpose scanning electron microscope REM 106I, equipped with a microanalysis system.
 Results. Based on the results of studies of the influence of the gas mixture concentration on the structure and composition of the cathodes, technological modes of melting were established, which made it possible to improve the quality indicators and economic indicators of the investigated cathodes. This will have a positive effect on the number of cathode failures, the performance of coated parts and the life of aircraft engines in general.
 Scientific novelty. The dependence of the influence of the concentration of the mixture of gases (argon-helium) was determined, which made it possible to obtain the optimal ratio of protective gases. With a gas ratio of 70/30 %, the highest quality cathodes were obtained, which were used for further research.
 Practical value. Quality of coating sputtering is determined by regimes of sputtering and quality of cathode itself. One of applied methods is by-layered melting of cathodes in copper water-cooled crystallizer using electrodes that are melted or non-melted. Optimal ratio of protective gases for receiving qualitative cathodes is determined.","PeriodicalId":489209,"journal":{"name":"Novì materìali ì tehnologìï v metalurgìï ta mašinobuduvannì","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136253129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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