In this study, structural changes in aluminum-chromium powder compacts were considered during exposure in the air at 500 °C. The samples were obtained by pressing the mixture of aluminum and chromium powders. The studies were carried out with using the X-ray diffraction and the metallographic analysis and by measuring the weight gain of the samples. It was established that the value of the specific mass gain has a complex and ambiguous dependence on the initial porosity of Al-Cr compacts due to phase transformations in powder mixtures. At short-term (up to 30 minutes) 500 °C air heating of the porous compacts significant oxidation does not occur. However, at the long-term exposure at 500 °C the reaction diffusion between aluminum and chromium occurs resulting in Al13Cr2 intermetallic formation and compacts swelling.In this study, structural changes in aluminum-chromium powder compacts were considered during exposure in the air at 500 °C. The samples were obtained by pressing the mixture of aluminum and chromium powders. The studies were carried out with using the X-ray diffraction and the metallographic analysis and by measuring the weight gain of the samples. It was established that the value of the specific mass gain has a complex and ambiguous dependence on the initial porosity of Al-Cr compacts due to phase transformations in powder mixtures. At short-term (up to 30 minutes) 500 °C air heating of the porous compacts significant oxidation does not occur. However, at the long-term exposure at 500 °C the reaction diffusion between aluminum and chromium occurs resulting in Al13Cr2 intermetallic formation and compacts swelling.
{"title":"Structural transformations in air heated Al-Cr powder compacts","authors":"G. A. Pribytkov, V. Korzhova, E. Korosteleva","doi":"10.1063/1.5132156","DOIUrl":"https://doi.org/10.1063/1.5132156","url":null,"abstract":"In this study, structural changes in aluminum-chromium powder compacts were considered during exposure in the air at 500 °C. The samples were obtained by pressing the mixture of aluminum and chromium powders. The studies were carried out with using the X-ray diffraction and the metallographic analysis and by measuring the weight gain of the samples. It was established that the value of the specific mass gain has a complex and ambiguous dependence on the initial porosity of Al-Cr compacts due to phase transformations in powder mixtures. At short-term (up to 30 minutes) 500 °C air heating of the porous compacts significant oxidation does not occur. However, at the long-term exposure at 500 °C the reaction diffusion between aluminum and chromium occurs resulting in Al13Cr2 intermetallic formation and compacts swelling.In this study, structural changes in aluminum-chromium powder compacts were considered during exposure in the air at 500 °C. The samples were obtained by pressing the mixture of aluminum and chromium powders. The studies were carried out with using the X-ray diffraction and the metallographic analysis and by measuring the weight gain of the samples. It was established that the value of the specific mass gain has a complex and ambiguous dependence on the initial porosity of Al-Cr compacts due to phase transformations in powder mixtures. At short-term (up to 30 minutes) 500 °C air heating of the porous compacts significant oxidation does not occur. However, at the long-term exposure at 500 °C the reaction diffusion between aluminum and chromium occurs resulting in Al13Cr2 intermetallic formation and compacts swelling.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72641147","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}
The mechanical properties of heat-resistant low-activated 12% Cr ferritic-martensitic steel EK-181 are investigated during tensile tests at T = 20 °C and in the temperature range close to the operating temperatures of the nuclear reactor (T = 650 and 720 °C) after traditional heat (THT) and high-temperature thermomechanical treatments (HTMT). It is shown that the strength properties of steel after HTMT exceed the corresponding values after THT. The features of the steel microstructure near the neck of the samples deformed by tension at these temperatures using two processing methods are studied. It is shown that plastic deformation at T = 20 °C leads to the curvature and fragmentation of martensitic lamellae and the formation of new low-angle boundaries. Deformation near the operating temperature range contributes to the development of dynamic polygonization, recrystallization and increase in density and size of the precipitates. After HTMT these processes are less intensive compared to the structural state after THT. This is due to the higher density of nanosized precipitates of V(C, N) and the increased dislocation density after HTMT.The mechanical properties of heat-resistant low-activated 12% Cr ferritic-martensitic steel EK-181 are investigated during tensile tests at T = 20 °C and in the temperature range close to the operating temperatures of the nuclear reactor (T = 650 and 720 °C) after traditional heat (THT) and high-temperature thermomechanical treatments (HTMT). It is shown that the strength properties of steel after HTMT exceed the corresponding values after THT. The features of the steel microstructure near the neck of the samples deformed by tension at these temperatures using two processing methods are studied. It is shown that plastic deformation at T = 20 °C leads to the curvature and fragmentation of martensitic lamellae and the formation of new low-angle boundaries. Deformation near the operating temperature range contributes to the development of dynamic polygonization, recrystallization and increase in density and size of the precipitates. After HTMT these processes are less intensive compared to the structural sta...
{"title":"Deformed microstructure of ferritic-martensitic steel EK-181","authors":"K. Almaeva, N. Polekhina, I. Litovchenko","doi":"10.1063/1.5131881","DOIUrl":"https://doi.org/10.1063/1.5131881","url":null,"abstract":"The mechanical properties of heat-resistant low-activated 12% Cr ferritic-martensitic steel EK-181 are investigated during tensile tests at T = 20 °C and in the temperature range close to the operating temperatures of the nuclear reactor (T = 650 and 720 °C) after traditional heat (THT) and high-temperature thermomechanical treatments (HTMT). It is shown that the strength properties of steel after HTMT exceed the corresponding values after THT. The features of the steel microstructure near the neck of the samples deformed by tension at these temperatures using two processing methods are studied. It is shown that plastic deformation at T = 20 °C leads to the curvature and fragmentation of martensitic lamellae and the formation of new low-angle boundaries. Deformation near the operating temperature range contributes to the development of dynamic polygonization, recrystallization and increase in density and size of the precipitates. After HTMT these processes are less intensive compared to the structural state after THT. This is due to the higher density of nanosized precipitates of V(C, N) and the increased dislocation density after HTMT.The mechanical properties of heat-resistant low-activated 12% Cr ferritic-martensitic steel EK-181 are investigated during tensile tests at T = 20 °C and in the temperature range close to the operating temperatures of the nuclear reactor (T = 650 and 720 °C) after traditional heat (THT) and high-temperature thermomechanical treatments (HTMT). It is shown that the strength properties of steel after HTMT exceed the corresponding values after THT. The features of the steel microstructure near the neck of the samples deformed by tension at these temperatures using two processing methods are studied. It is shown that plastic deformation at T = 20 °C leads to the curvature and fragmentation of martensitic lamellae and the formation of new low-angle boundaries. Deformation near the operating temperature range contributes to the development of dynamic polygonization, recrystallization and increase in density and size of the precipitates. After HTMT these processes are less intensive compared to the structural sta...","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78180181","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}
The results of an experimental study of laser cutting of aluminum-lithium alloys using a repetitively pulsed CO2 laser with Q-switching under conditions of intense material evaporation are presented. The dependence of cut quality on the assisted gas pressure is determined. It is shown that a high-quality cut with a sheet thickness of 1.5 mm can be obtained at a gas pressure of 0.5–0.6 bar, which is significantly less compared to cutting with a continuous laser power. This makes it possible to reduce the assisted gas consumption. The dependence of cut surface roughness on the pulse repetition rate is measured.The results of an experimental study of laser cutting of aluminum-lithium alloys using a repetitively pulsed CO2 laser with Q-switching under conditions of intense material evaporation are presented. The dependence of cut quality on the assisted gas pressure is determined. It is shown that a high-quality cut with a sheet thickness of 1.5 mm can be obtained at a gas pressure of 0.5–0.6 bar, which is significantly less compared to cutting with a continuous laser power. This makes it possible to reduce the assisted gas consumption. The dependence of cut surface roughness on the pulse repetition rate is measured.
{"title":"Cutting of aluminum alloys with a Q-switched repetitively pulsed CO2 laser under conditions of intense material evaporation","authors":"V. Shulyatyev, A. Orishich","doi":"10.1063/1.5132201","DOIUrl":"https://doi.org/10.1063/1.5132201","url":null,"abstract":"The results of an experimental study of laser cutting of aluminum-lithium alloys using a repetitively pulsed CO2 laser with Q-switching under conditions of intense material evaporation are presented. The dependence of cut quality on the assisted gas pressure is determined. It is shown that a high-quality cut with a sheet thickness of 1.5 mm can be obtained at a gas pressure of 0.5–0.6 bar, which is significantly less compared to cutting with a continuous laser power. This makes it possible to reduce the assisted gas consumption. The dependence of cut surface roughness on the pulse repetition rate is measured.The results of an experimental study of laser cutting of aluminum-lithium alloys using a repetitively pulsed CO2 laser with Q-switching under conditions of intense material evaporation are presented. The dependence of cut quality on the assisted gas pressure is determined. It is shown that a high-quality cut with a sheet thickness of 1.5 mm can be obtained at a gas pressure of 0.5–0.6 bar, which is significantly less compared to cutting with a continuous laser power. This makes it possible to reduce the assisted gas consumption. The dependence of cut surface roughness on the pulse repetition rate is measured.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79059686","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}
The microstructural evolution in Fe-13Mn-1.3C, Fe-13Mn-2.7Al-1.3C and Fe-28Mn-2.7Al-1.3C (wt %) steels with different stacking faults energies processed by high-pressure torsion (HPT) were studied in dependence on the temperature of post-HPT anneal. HPT-assisted microstructure with high fraction of twin boundaries in Fe-28Mn-2.7Al-1.3C steel possess the highest stability (up to 600°C) during post-deformation annealing in comparison with two other steels. Independently on steel composition and tendency to phase transformation, a recrystallization occurs during annealing at temperature 700°C and fine-grained austenitic microstructure forms in all steels. Annealing at 700°C promotes formation of inhomogeneous microstructure with predominant growth of individual grains in Fe-13Mn-1.3C, Fe-28Mn-2.7Al-1.3C steels, which are more stable to phase transformation during annealing as compared to Fe-13Mn-2.7Al-1.3C steel.The microstructural evolution in Fe-13Mn-1.3C, Fe-13Mn-2.7Al-1.3C and Fe-28Mn-2.7Al-1.3C (wt %) steels with different stacking faults energies processed by high-pressure torsion (HPT) were studied in dependence on the temperature of post-HPT anneal. HPT-assisted microstructure with high fraction of twin boundaries in Fe-28Mn-2.7Al-1.3C steel possess the highest stability (up to 600°C) during post-deformation annealing in comparison with two other steels. Independently on steel composition and tendency to phase transformation, a recrystallization occurs during annealing at temperature 700°C and fine-grained austenitic microstructure forms in all steels. Annealing at 700°C promotes formation of inhomogeneous microstructure with predominant growth of individual grains in Fe-13Mn-1.3C, Fe-28Mn-2.7Al-1.3C steels, which are more stable to phase transformation during annealing as compared to Fe-13Mn-2.7Al-1.3C steel.
{"title":"Anneal-behavior of deformation microstructure and microhardness of high-Mn austenitic steels processed by high-pressure torsion","authors":"G. Maier","doi":"10.1063/1.5132072","DOIUrl":"https://doi.org/10.1063/1.5132072","url":null,"abstract":"The microstructural evolution in Fe-13Mn-1.3C, Fe-13Mn-2.7Al-1.3C and Fe-28Mn-2.7Al-1.3C (wt %) steels with different stacking faults energies processed by high-pressure torsion (HPT) were studied in dependence on the temperature of post-HPT anneal. HPT-assisted microstructure with high fraction of twin boundaries in Fe-28Mn-2.7Al-1.3C steel possess the highest stability (up to 600°C) during post-deformation annealing in comparison with two other steels. Independently on steel composition and tendency to phase transformation, a recrystallization occurs during annealing at temperature 700°C and fine-grained austenitic microstructure forms in all steels. Annealing at 700°C promotes formation of inhomogeneous microstructure with predominant growth of individual grains in Fe-13Mn-1.3C, Fe-28Mn-2.7Al-1.3C steels, which are more stable to phase transformation during annealing as compared to Fe-13Mn-2.7Al-1.3C steel.The microstructural evolution in Fe-13Mn-1.3C, Fe-13Mn-2.7Al-1.3C and Fe-28Mn-2.7Al-1.3C (wt %) steels with different stacking faults energies processed by high-pressure torsion (HPT) were studied in dependence on the temperature of post-HPT anneal. HPT-assisted microstructure with high fraction of twin boundaries in Fe-28Mn-2.7Al-1.3C steel possess the highest stability (up to 600°C) during post-deformation annealing in comparison with two other steels. Independently on steel composition and tendency to phase transformation, a recrystallization occurs during annealing at temperature 700°C and fine-grained austenitic microstructure forms in all steels. Annealing at 700°C promotes formation of inhomogeneous microstructure with predominant growth of individual grains in Fe-13Mn-1.3C, Fe-28Mn-2.7Al-1.3C steels, which are more stable to phase transformation during annealing as compared to Fe-13Mn-2.7Al-1.3C steel.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81581027","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}
The article describes the results of molecular dynamics modeling of scratch induced plastic deformation in a nanosized titanium polycrystalline. Coherent and incoherent twins are in the focus of present research. It is established that the development of plastic deformation is determined by the twin boundary type. In the case of incoherent twin boundary there is a nanofragmentation of the material and the curvature of the boundary plane. For the crystallite with coherent twin boundary, the plastic deformation is possible due to the reorientation of the twin lattice into the matrix lattice. This is due to the perfect similarity of two lattices and the lower specific energy of such a defect. These results make it possible to understand better the features of the development of plastic deformation in the surface layers of materials with hcp structure.The article describes the results of molecular dynamics modeling of scratch induced plastic deformation in a nanosized titanium polycrystalline. Coherent and incoherent twins are in the focus of present research. It is established that the development of plastic deformation is determined by the twin boundary type. In the case of incoherent twin boundary there is a nanofragmentation of the material and the curvature of the boundary plane. For the crystallite with coherent twin boundary, the plastic deformation is possible due to the reorientation of the twin lattice into the matrix lattice. This is due to the perfect similarity of two lattices and the lower specific energy of such a defect. These results make it possible to understand better the features of the development of plastic deformation in the surface layers of materials with hcp structure.
{"title":"MD study of scratching-induced deformation in nanosized polycrystalline titanium with coherent and incoherent twins boundaries","authors":"A. Dmitriev, A. Nikonov, A. Shugurov","doi":"10.1063/1.5131938","DOIUrl":"https://doi.org/10.1063/1.5131938","url":null,"abstract":"The article describes the results of molecular dynamics modeling of scratch induced plastic deformation in a nanosized titanium polycrystalline. Coherent and incoherent twins are in the focus of present research. It is established that the development of plastic deformation is determined by the twin boundary type. In the case of incoherent twin boundary there is a nanofragmentation of the material and the curvature of the boundary plane. For the crystallite with coherent twin boundary, the plastic deformation is possible due to the reorientation of the twin lattice into the matrix lattice. This is due to the perfect similarity of two lattices and the lower specific energy of such a defect. These results make it possible to understand better the features of the development of plastic deformation in the surface layers of materials with hcp structure.The article describes the results of molecular dynamics modeling of scratch induced plastic deformation in a nanosized titanium polycrystalline. Coherent and incoherent twins are in the focus of present research. It is established that the development of plastic deformation is determined by the twin boundary type. In the case of incoherent twin boundary there is a nanofragmentation of the material and the curvature of the boundary plane. For the crystallite with coherent twin boundary, the plastic deformation is possible due to the reorientation of the twin lattice into the matrix lattice. This is due to the perfect similarity of two lattices and the lower specific energy of such a defect. These results make it possible to understand better the features of the development of plastic deformation in the surface layers of materials with hcp structure.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81588260","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}
The paper studies the potential applicability of Hurst exponent for estimation of dynamics of volume electrical resistance of carbon black filled rubbers operating in aggressive media, such as air, transformer oil, and toluene. The proposed approach for analysis of filled polymers’ behavior is confirmed experimentally to be successful. It is concluded that Hurst exponent can be used to analyze time series trends of volume electrical resistance changes caused by aggressive media mentioned earlier. Peculiar features of Hurst exponent are shown for various concentrations of an electrically conductive filler, different environments, and time series length.
{"title":"Hurst exponent-based analysis of the behavior of filled polymers in aggressive media","authors":"N. Minakova, A. V. Mansurov","doi":"10.1063/1.5132091","DOIUrl":"https://doi.org/10.1063/1.5132091","url":null,"abstract":"The paper studies the potential applicability of Hurst exponent for estimation of dynamics of volume electrical resistance of carbon black filled rubbers operating in aggressive media, such as air, transformer oil, and toluene. The proposed approach for analysis of filled polymers’ behavior is confirmed experimentally to be successful. It is concluded that Hurst exponent can be used to analyze time series trends of volume electrical resistance changes caused by aggressive media mentioned earlier. Peculiar features of Hurst exponent are shown for various concentrations of an electrically conductive filler, different environments, and time series length.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85125513","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}
Experimental studies are aimed at exploring the possibilities of new materials using for LOM technology. This article is devoted to numerical simulation of structural transformation occurring in an adhesive layer of three-layer object. A mathematical model describing the physical process is formulated. Numerical implementation of the model shows the effect of technological parameters on structural transformation in the sample.Experimental studies are aimed at exploring the possibilities of new materials using for LOM technology. This article is devoted to numerical simulation of structural transformation occurring in an adhesive layer of three-layer object. A mathematical model describing the physical process is formulated. Numerical implementation of the model shows the effect of technological parameters on structural transformation in the sample.
{"title":"Kinetics of structural transformation in an adhesive layer during creation of 3D objects in LOM technology","authors":"E. Saifullin, A. Knyazeva","doi":"10.1063/1.5132171","DOIUrl":"https://doi.org/10.1063/1.5132171","url":null,"abstract":"Experimental studies are aimed at exploring the possibilities of new materials using for LOM technology. This article is devoted to numerical simulation of structural transformation occurring in an adhesive layer of three-layer object. A mathematical model describing the physical process is formulated. Numerical implementation of the model shows the effect of technological parameters on structural transformation in the sample.Experimental studies are aimed at exploring the possibilities of new materials using for LOM technology. This article is devoted to numerical simulation of structural transformation occurring in an adhesive layer of three-layer object. A mathematical model describing the physical process is formulated. Numerical implementation of the model shows the effect of technological parameters on structural transformation in the sample.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85864400","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}
The modern practice of treating patients with impaired motor functions often consists in replacing the natural joints with artificial ones. Currently, more than 1.5 million hip joint replacements are performed annually in the world, with a tendency to grow. Even if the replacement procedure is successful, replacement is often ineffective in the medium or long term, due to various complications. The paper puts forward ideas and discusses how to mechanically load the joint to promote the development of regenerative effects, while minimizing the influence of factors determining wear.The modern practice of treating patients with impaired motor functions often consists in replacing the natural joints with artificial ones. Currently, more than 1.5 million hip joint replacements are performed annually in the world, with a tendency to grow. Even if the replacement procedure is successful, replacement is often ineffective in the medium or long term, due to various complications. The paper puts forward ideas and discusses how to mechanically load the joint to promote the development of regenerative effects, while minimizing the influence of factors determining wear.
{"title":"Active bio contact mechanics: Concepts of active control of wear and growth of the cartilage in natural joints","authors":"V. Popov","doi":"10.1063/1.5132152","DOIUrl":"https://doi.org/10.1063/1.5132152","url":null,"abstract":"The modern practice of treating patients with impaired motor functions often consists in replacing the natural joints with artificial ones. Currently, more than 1.5 million hip joint replacements are performed annually in the world, with a tendency to grow. Even if the replacement procedure is successful, replacement is often ineffective in the medium or long term, due to various complications. The paper puts forward ideas and discusses how to mechanically load the joint to promote the development of regenerative effects, while minimizing the influence of factors determining wear.The modern practice of treating patients with impaired motor functions often consists in replacing the natural joints with artificial ones. Currently, more than 1.5 million hip joint replacements are performed annually in the world, with a tendency to grow. Even if the replacement procedure is successful, replacement is often ineffective in the medium or long term, due to various complications. The paper puts forward ideas and discusses how to mechanically load the joint to promote the development of regenerative effects, while minimizing the influence of factors determining wear.","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87971046","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}
In the framework of the asymmetric theory of the elastic-plastic Cosserat continuum in a two-dimensional formulation for plane strain, the simulation of inelastic localized deformation was performed for homogeneous samples and the mesoscale volumes of the polycrystalline material. It is assumed that the development of rotational deformation modes in loaded materials is associated with the development of localized plastic deformation in them and the formation of curvatures of the crystal lattice in the material at the micro and nanoscales. For this reason, the parameters of the Cosserat model are considered as functions of inelastic strain for each local volume of the medium. It is shown that the couple stress forming at the mesoscale makes a significant contribution to the hardening of macroscopic stress-strain curves. The simulation results show that if the rotation modes of deformation are blocked in the loaded material, the accommodation capacity of the material decreases, the local and macroscopic degree of inelastic strain sharply increases and fracture patterns are formed much faster. Conversely, the creation of meso- and nanosized substructures with a high curvature of the crystal lattice in materials contributes to the activation of rotational deformation modes, reducing the degree of localized strain and relaxation of dangerous stress concentrators.In the framework of the asymmetric theory of the elastic-plastic Cosserat continuum in a two-dimensional formulation for plane strain, the simulation of inelastic localized deformation was performed for homogeneous samples and the mesoscale volumes of the polycrystalline material. It is assumed that the development of rotational deformation modes in loaded materials is associated with the development of localized plastic deformation in them and the formation of curvatures of the crystal lattice in the material at the micro and nanoscales. For this reason, the parameters of the Cosserat model are considered as functions of inelastic strain for each local volume of the medium. It is shown that the couple stress forming at the mesoscale makes a significant contribution to the hardening of macroscopic stress-strain curves. The simulation results show that if the rotation modes of deformation are blocked in the loaded material, the accommodation capacity of the material decreases, the local and macroscopic deg...
{"title":"Role of the mesoscopic rotation modes of deformation in formation of macroscopic stress–strain curves","authors":"I. Smolin, P. Makarov, R. Bakeev","doi":"10.1063/1.5132211","DOIUrl":"https://doi.org/10.1063/1.5132211","url":null,"abstract":"In the framework of the asymmetric theory of the elastic-plastic Cosserat continuum in a two-dimensional formulation for plane strain, the simulation of inelastic localized deformation was performed for homogeneous samples and the mesoscale volumes of the polycrystalline material. It is assumed that the development of rotational deformation modes in loaded materials is associated with the development of localized plastic deformation in them and the formation of curvatures of the crystal lattice in the material at the micro and nanoscales. For this reason, the parameters of the Cosserat model are considered as functions of inelastic strain for each local volume of the medium. It is shown that the couple stress forming at the mesoscale makes a significant contribution to the hardening of macroscopic stress-strain curves. The simulation results show that if the rotation modes of deformation are blocked in the loaded material, the accommodation capacity of the material decreases, the local and macroscopic degree of inelastic strain sharply increases and fracture patterns are formed much faster. Conversely, the creation of meso- and nanosized substructures with a high curvature of the crystal lattice in materials contributes to the activation of rotational deformation modes, reducing the degree of localized strain and relaxation of dangerous stress concentrators.In the framework of the asymmetric theory of the elastic-plastic Cosserat continuum in a two-dimensional formulation for plane strain, the simulation of inelastic localized deformation was performed for homogeneous samples and the mesoscale volumes of the polycrystalline material. It is assumed that the development of rotational deformation modes in loaded materials is associated with the development of localized plastic deformation in them and the formation of curvatures of the crystal lattice in the material at the micro and nanoscales. For this reason, the parameters of the Cosserat model are considered as functions of inelastic strain for each local volume of the medium. It is shown that the couple stress forming at the mesoscale makes a significant contribution to the hardening of macroscopic stress-strain curves. The simulation results show that if the rotation modes of deformation are blocked in the loaded material, the accommodation capacity of the material decreases, the local and macroscopic deg...","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88025441","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}
The degradation of feedstock entering the refinery, leads to the need to increase the depth of oil refining. One of the promising methods for the processing of heavy hydrocarbon feedstocks is the combination of oxidation and subsequent cracking, which makes it possible to effectively remove polyaromatic sulfur compounds and to obtain additional quantities of distillate fractions. To develop effective methods of cracking of the products of oxidation of sulfur compounds, it is necessary to establish their thermal stability and the dependence of changes in the composition and properties of products on the conditions of oxidation and subsequent cracking. Vacuum gas oil was oxidized with a mixture of hydrogen peroxide with formic acid. The oxidized gas oil was cracked or divided into polar and non-polar components, with subsequent cracking. The composition of sulfur compounds of the cracking products was analyzed by chromatographic methods. Selective cracking of polar and non-polar components allows reducing gas formation and increasing the yield in distillate fractions. Depending on the conditions, reactions of cracking of oxidized sulfur compounds can proceed with the formation of a wide range of thiophene derivatives. Further investigations will allow gaining a better understanding of the patterns of transformations of sulfur-containing compounds of vacuum distillates in oxidative and thermal processes.The degradation of feedstock entering the refinery, leads to the need to increase the depth of oil refining. One of the promising methods for the processing of heavy hydrocarbon feedstocks is the combination of oxidation and subsequent cracking, which makes it possible to effectively remove polyaromatic sulfur compounds and to obtain additional quantities of distillate fractions. To develop effective methods of cracking of the products of oxidation of sulfur compounds, it is necessary to establish their thermal stability and the dependence of changes in the composition and properties of products on the conditions of oxidation and subsequent cracking. Vacuum gas oil was oxidized with a mixture of hydrogen peroxide with formic acid. The oxidized gas oil was cracked or divided into polar and non-polar components, with subsequent cracking. The composition of sulfur compounds of the cracking products was analyzed by chromatographic methods. Selective cracking of polar and non-polar components allows reducing g...
{"title":"Composition of products of cracking of oxidized sulfur-containing vacuum gasoil components","authors":"Yulia A. Yovik, E. B. Krivtsov, A. Golovko","doi":"10.1063/1.5132261","DOIUrl":"https://doi.org/10.1063/1.5132261","url":null,"abstract":"The degradation of feedstock entering the refinery, leads to the need to increase the depth of oil refining. One of the promising methods for the processing of heavy hydrocarbon feedstocks is the combination of oxidation and subsequent cracking, which makes it possible to effectively remove polyaromatic sulfur compounds and to obtain additional quantities of distillate fractions. To develop effective methods of cracking of the products of oxidation of sulfur compounds, it is necessary to establish their thermal stability and the dependence of changes in the composition and properties of products on the conditions of oxidation and subsequent cracking. Vacuum gas oil was oxidized with a mixture of hydrogen peroxide with formic acid. The oxidized gas oil was cracked or divided into polar and non-polar components, with subsequent cracking. The composition of sulfur compounds of the cracking products was analyzed by chromatographic methods. Selective cracking of polar and non-polar components allows reducing gas formation and increasing the yield in distillate fractions. Depending on the conditions, reactions of cracking of oxidized sulfur compounds can proceed with the formation of a wide range of thiophene derivatives. Further investigations will allow gaining a better understanding of the patterns of transformations of sulfur-containing compounds of vacuum distillates in oxidative and thermal processes.The degradation of feedstock entering the refinery, leads to the need to increase the depth of oil refining. One of the promising methods for the processing of heavy hydrocarbon feedstocks is the combination of oxidation and subsequent cracking, which makes it possible to effectively remove polyaromatic sulfur compounds and to obtain additional quantities of distillate fractions. To develop effective methods of cracking of the products of oxidation of sulfur compounds, it is necessary to establish their thermal stability and the dependence of changes in the composition and properties of products on the conditions of oxidation and subsequent cracking. Vacuum gas oil was oxidized with a mixture of hydrogen peroxide with formic acid. The oxidized gas oil was cracked or divided into polar and non-polar components, with subsequent cracking. The composition of sulfur compounds of the cracking products was analyzed by chromatographic methods. Selective cracking of polar and non-polar components allows reducing g...","PeriodicalId":20637,"journal":{"name":"PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88645643","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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