Pub Date : 1900-01-01DOI: 10.18323/2782-4039-2022-3-2-79-89
A. Frik, M. Nikitina, R. Islamgaliev
A crucial aspect in the development of materials with improved functional properties is ensuring their ability to withstand the operating temperatures of a finished product. To increase the service life and efficiency of products made of ferrite-martensite steels, various types of deformation and thermal treatments are used. The authors studied the influence of different temperature regimes on the structure and thermal stability of ЭИ-961Ш ferrite-martensite steel subjected to rolling and additional hardening. As a method of deformation and heat treatment, the authors used cold rolling followed by re-quenching from a temperature above the ferrite/austenite phase transition. The samples were rolled during several passes on a laboratory rolling mill with the deformation of 6 % per pass for a final thickness of 4.3 mm to a reduction degree of 70 %. The authors carried out structural studies by transmission electron microscopy and scanning electron microscopy. The study showed that as a rolling result, a bimodal band structure forms with the distribution of Cr23C6 carbide particles along the grain boundaries. When using additional hardening, an increase in the globular carbides proportion is observed, and during the study by transmission electron microscopy, nano-twins were found in the structure. The bands’ width after the reduction by 50 % was 0.5 microns and after cold rolling and additional heat treatment – 0.4 microns. The authors carried out short annealing in the operating temperature range to study the thermal stability of ferrite/martensite steel structure after cold rolling and additional heat treatment. The thermal stability study showed that many structural features formed during previous deformation and heat treatment are preserved, however, after annealing at 600 °C, there are no visually observable nano-twins in the structure.
{"title":"Thermal stability of the ЭИ-961Ш steel structure after combined processing","authors":"A. Frik, M. Nikitina, R. Islamgaliev","doi":"10.18323/2782-4039-2022-3-2-79-89","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-3-2-79-89","url":null,"abstract":"A crucial aspect in the development of materials with improved functional properties is ensuring their ability to withstand the operating temperatures of a finished product. To increase the service life and efficiency of products made of ferrite-martensite steels, various types of deformation and thermal treatments are used. The authors studied the influence of different temperature regimes on the structure and thermal stability of ЭИ-961Ш ferrite-martensite steel subjected to rolling and additional hardening. As a method of deformation and heat treatment, the authors used cold rolling followed by re-quenching from a temperature above the ferrite/austenite phase transition. The samples were rolled during several passes on a laboratory rolling mill with the deformation of 6 % per pass for a final thickness of 4.3 mm to a reduction degree of 70 %. The authors carried out structural studies by transmission electron microscopy and scanning electron microscopy. The study showed that as a rolling result, a bimodal band structure forms with the distribution of Cr23C6 carbide particles along the grain boundaries. When using additional hardening, an increase in the globular carbides proportion is observed, and during the study by transmission electron microscopy, nano-twins were found in the structure. The bands’ width after the reduction by 50 % was 0.5 microns and after cold rolling and additional heat treatment – 0.4 microns. The authors carried out short annealing in the operating temperature range to study the thermal stability of ferrite/martensite steel structure after cold rolling and additional heat treatment. The thermal stability study showed that many structural features formed during previous deformation and heat treatment are preserved, however, after annealing at 600 °C, there are no visually observable nano-twins in the structure.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132875886","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 : 1900-01-01DOI: 10.18323/2782-4039-2022-4-49-69
P. V. Ivashin, M. M. Krishtal, A. Tverdokhlebov, A. Polunin, N. Dudareva, A. Kruglov
Oxide layers formed by plasma-electrolytic oxidation (PEO) are characterized by a sufficiently high porosity, which influences almost the whole complex of service characteristics. However, the known data on the integral porosity of PEO-produced layers are rather contradictory, and the nature of the pore size distribution in these layers remains understudied. As a result of processing the images of the layer cross-section produced in a wide magnification range (scanning electron microscopy – SEM, image-based analysis), the authors obtained the pore size distribution in the range of 10 nm to 10 µm, which is sufficiently well described by a lognormal distribution function (pore geometry was approximated by a spherical shape). Such distribution pattern indicates the nature of pore formation, which can be related to the thermally activated process of gas emission from a liquid melt, the volume and average temperature of which, in their turn, depend on the micro-arc discharge energy. The paper presents the results of identifying the oxide layer phase composition and crystallites sizes by the X-ray crystallography method. Comparing the results of X-ray spectral microanalysis and X-ray crystallography, the amorphous component phase composition was evaluated. Using the stationary method and the method of pulsed laser heating, the authors determined the thermal conductivity of the initial oxide layer and the layer after the removal of its highly-porous outer part. The porosity values obtained experimentally and calculated based on the analysis of SEM-images and the results of determining the phase composition, including amorphous phases, allowed evaluating the oxide layer thermal conductivity with the help of four known analytical models. The results of calculating the thermal conductivity using the Loeb model showed good convergence with the experimental results obtained in this work. The modeling demonstrated that the size of crystallites influence the oxide layer thermal conductivity much less than the porosity and amorphous phase.
{"title":"Different-sized porosity and thermal conductivity of oxide layers formed by plasma-electrolytic oxidation on the AK12D silumin","authors":"P. V. Ivashin, M. M. Krishtal, A. Tverdokhlebov, A. Polunin, N. Dudareva, A. Kruglov","doi":"10.18323/2782-4039-2022-4-49-69","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-4-49-69","url":null,"abstract":"Oxide layers formed by plasma-electrolytic oxidation (PEO) are characterized by a sufficiently high porosity, which influences almost the whole complex of service characteristics. However, the known data on the integral porosity of PEO-produced layers are rather contradictory, and the nature of the pore size distribution in these layers remains understudied. As a result of processing the images of the layer cross-section produced in a wide magnification range (scanning electron microscopy – SEM, image-based analysis), the authors obtained the pore size distribution in the range of 10 nm to 10 µm, which is sufficiently well described by a lognormal distribution function (pore geometry was approximated by a spherical shape). Such distribution pattern indicates the nature of pore formation, which can be related to the thermally activated process of gas emission from a liquid melt, the volume and average temperature of which, in their turn, depend on the micro-arc discharge energy. The paper presents the results of identifying the oxide layer phase composition and crystallites sizes by the X-ray crystallography method. Comparing the results of X-ray spectral microanalysis and X-ray crystallography, the amorphous component phase composition was evaluated. Using the stationary method and the method of pulsed laser heating, the authors determined the thermal conductivity of the initial oxide layer and the layer after the removal of its highly-porous outer part. The porosity values obtained experimentally and calculated based on the analysis of SEM-images and the results of determining the phase composition, including amorphous phases, allowed evaluating the oxide layer thermal conductivity with the help of four known analytical models. The results of calculating the thermal conductivity using the Loeb model showed good convergence with the experimental results obtained in this work. The modeling demonstrated that the size of crystallites influence the oxide layer thermal conductivity much less than the porosity and amorphous phase.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116317661","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 : 1900-01-01DOI: 10.18323/2782-4039-2022-4-38-48
A. Drits, E. V. Aryshenskii, E. Kudryavtsev, I. A. Zorin, S. Konovalov
Magnesium-rich aluminum alloys with small scandium additives are widely used in many branches of modern industry due to the high level of their mechanical properties. However, the issue of low thermal stability of Al3Sc particles, which does not allow performing deformation processing of this group of alloys at a temperature above 400 °С, continues to be relevant. Hafnium addition can become one of the ways to solve this problem as hafnium forms a shell around the Al3Sc particles and, due to the low diffusion coefficient in the aluminum matrix, reduces their coagulation rate. The paper studies the influence of addition of 0.2 % and 0.5 % Hf on the electrical conductivity and the process of supersaturated solid solution decomposition, as well as on the size and quantity of nanoparticles in the 1570 magnesium-rich aluminum alloy at its thermal treatment. The authors studied the kinetics of supersaturated solid solution decomposition in the 1570, 1570–0.2Hf, and 1570–0.5Hf alloys by the electrical conductivity measuring and constructed C-curves describing the supersaturated solid solution decomposition in the studied alloys in the temperature range of 260–440 °С. Besides, using transmission electron microscopy, the strengthening nanoparticles of the 1570 and 1570–0.5Hf alloys were studied during heating to 370 °C and 4-hour soaking. The study showed that hafnium addition significantly slows down the supersaturated solid solution decomposition in the 1570 alloy. The authors identified that in the alloys with hafnium additives, the supersaturated solid solution decomposition is the most intense at a temperature of 350 °С, and in the alloys without hafnium – at a temperature of 430 °С. The transmission microscopy data confirm that the 1570 alloy without hafnium contains 3–4.5 times more nanoparticles than the 1570–0.5Hf alloy.
{"title":"The study of supersaturated solid solution decomposition in magnesium-rich aluminum alloys with scandium and hafnium additions","authors":"A. Drits, E. V. Aryshenskii, E. Kudryavtsev, I. A. Zorin, S. Konovalov","doi":"10.18323/2782-4039-2022-4-38-48","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-4-38-48","url":null,"abstract":"Magnesium-rich aluminum alloys with small scandium additives are widely used in many branches of modern industry due to the high level of their mechanical properties. However, the issue of low thermal stability of Al3Sc particles, which does not allow performing deformation processing of this group of alloys at a temperature above 400 °С, continues to be relevant. Hafnium addition can become one of the ways to solve this problem as hafnium forms a shell around the Al3Sc particles and, due to the low diffusion coefficient in the aluminum matrix, reduces their coagulation rate. The paper studies the influence of addition of 0.2 % and 0.5 % Hf on the electrical conductivity and the process of supersaturated solid solution decomposition, as well as on the size and quantity of nanoparticles in the 1570 magnesium-rich aluminum alloy at its thermal treatment. The authors studied the kinetics of supersaturated solid solution decomposition in the 1570, 1570–0.2Hf, and 1570–0.5Hf alloys by the electrical conductivity measuring and constructed C-curves describing the supersaturated solid solution decomposition in the studied alloys in the temperature range of 260–440 °С. Besides, using transmission electron microscopy, the strengthening nanoparticles of the 1570 and 1570–0.5Hf alloys were studied during heating to 370 °C and 4-hour soaking. The study showed that hafnium addition significantly slows down the supersaturated solid solution decomposition in the 1570 alloy. The authors identified that in the alloys with hafnium additives, the supersaturated solid solution decomposition is the most intense at a temperature of 350 °С, and in the alloys without hafnium – at a temperature of 430 °С. The transmission microscopy data confirm that the 1570 alloy without hafnium contains 3–4.5 times more nanoparticles than the 1570–0.5Hf alloy.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116349134","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 : 1900-01-01DOI: 10.18323/2782-4039-2023-1-69-81
E. Priymak, E. Kuzmina, S. Gladkovskii, D. Vichuzhanin, V. Veselova
Rotary friction welding (RFW) is used in the production of drill pipes for solid mineral prospecting. The need for the creation of the lightened drill strings for high-speed diamond drilling of ultradeep wells dictates the necessity of a greater focus on the study of a weld zone and setting the RFW technological parameters. This paper presents the results of experimental studies of a welded joint of a drill pipe of the H standard size according to ISO 10097, made of the 30ХГСА (pipe body) and 40ХМФА (tool joint) steels under the cyclic loads. The authors evaluated the influence of the force applied to the workpieces in the process of friction of the contacting surfaces (force during heating), and postweld tempering at a temperature of 550 °С on the cyclic life of welded joints, under the conditions of alternate tension-compression at the cycle amplitude stress of ±420 MPa. The study determined that with an increase in the force during heating, the microstructure changes occur in the zone of thermomechanical influence, contributing to an increase in the fatigue strength of welded joints. The authors identified the negative effect of postweld tempering on the fatigue strength of welded joints, which is expressed in the decrease in the number of cycles before failure by 15–40 %, depending on the magnitude of the force during heating. The optimal RFW mode of the specified combination of steels is determined, which provides the largest number of cycles before failure: the force during heating (at friction) Fh=120 kN, forging force Ffor=160 kN, rotational frequency during heating n=800 Rpm, and upset during heating l=8 mm. A series of fatigue tests have been carried out at various values of the cycle amplitude stress of the welded joint produced at the optimal mode and the 30ХГСА steel base metal; limited endurance curves have been plotted. It is shown that the differences in the limited endurance curves of the pipe body material (30ХГСА steel) and the welded joint are insignificant. The obtained results are supplemented by the microhardness measurement data and fractographs of fractured samples, revealing the mechanism of crack propagation under the cyclic loads.
{"title":"Fatigue strength of 30ХГСА–40ХМФА welded joints produced by rotary friction welding","authors":"E. Priymak, E. Kuzmina, S. Gladkovskii, D. Vichuzhanin, V. Veselova","doi":"10.18323/2782-4039-2023-1-69-81","DOIUrl":"https://doi.org/10.18323/2782-4039-2023-1-69-81","url":null,"abstract":"Rotary friction welding (RFW) is used in the production of drill pipes for solid mineral prospecting. The need for the creation of the lightened drill strings for high-speed diamond drilling of ultradeep wells dictates the necessity of a greater focus on the study of a weld zone and setting the RFW technological parameters. This paper presents the results of experimental studies of a welded joint of a drill pipe of the H standard size according to ISO 10097, made of the 30ХГСА (pipe body) and 40ХМФА (tool joint) steels under the cyclic loads. The authors evaluated the influence of the force applied to the workpieces in the process of friction of the contacting surfaces (force during heating), and postweld tempering at a temperature of 550 °С on the cyclic life of welded joints, under the conditions of alternate tension-compression at the cycle amplitude stress of ±420 MPa. The study determined that with an increase in the force during heating, the microstructure changes occur in the zone of thermomechanical influence, contributing to an increase in the fatigue strength of welded joints. The authors identified the negative effect of postweld tempering on the fatigue strength of welded joints, which is expressed in the decrease in the number of cycles before failure by 15–40 %, depending on the magnitude of the force during heating. The optimal RFW mode of the specified combination of steels is determined, which provides the largest number of cycles before failure: the force during heating (at friction) Fh=120 kN, forging force Ffor=160 kN, rotational frequency during heating n=800 Rpm, and upset during heating l=8 mm. A series of fatigue tests have been carried out at various values of the cycle amplitude stress of the welded joint produced at the optimal mode and the 30ХГСА steel base metal; limited endurance curves have been plotted. It is shown that the differences in the limited endurance curves of the pipe body material (30ХГСА steel) and the welded joint are insignificant. The obtained results are supplemented by the microhardness measurement data and fractographs of fractured samples, revealing the mechanism of crack propagation under the cyclic loads.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121784813","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 : 1900-01-01DOI: 10.18323/2782-4039-2022-3-2-32-43
K. Ramazanov, E. Vardanyan, V. Mukhamadeev, A. Nazarov, I. Mukhamadeev, A. Nikolaev
The paper presents the results of the study of the component composition of the reaction gases mixture when synthesizing carbonitride coatings of the Ti–Al–C–N system influencing the cutting tool durability. The coating was applied using the updated unit NNV-6.6-I1 by spraying from two one-component cathodes assisted by the incandescent cathode plasma source. During applying the coating, the mixture of reaction gases of N2 nitrogen and C2H2 acetylene in the ratio of 1:4, 2:3, 3:2, and 4:1 was delivered to the chamber. The paper presents the results of measuring the microhardness of studied specimens, which show that a sample with the coating deposited at the reaction gases ratio of N2:C2H2=2:3 had the largest microhardness value (4870 HV0.05). The paper presents the results of field tests of carbide-tipped tools with the studied coatings. Durability tests identified that a cutter with the coating deposited at the gas ratio of N2:C2H2=4:1 increases the tool durability ten times compared to a cutting tool without coating. Using the electron microscopy method, the authors investigated the chemical composition of the tool cutting face after tests. The analysis of the chemical composition of the surface after cutting showed that the content of coating elements on the surface of the sample with a coating deposited at the 4:1 ratio of the reaction gases of nitrogen and acetylene was considerably higher than that of other studied coatings, which indicates the less coating wear. However, ferrum is present in some areas of the cutting face, which says about the adhesion of treated material to the tool.
{"title":"The study of influence of the reaction gases ratio at the Ti–Al–C–N coating deposition on the cutting tool wear resistance","authors":"K. Ramazanov, E. Vardanyan, V. Mukhamadeev, A. Nazarov, I. Mukhamadeev, A. Nikolaev","doi":"10.18323/2782-4039-2022-3-2-32-43","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-3-2-32-43","url":null,"abstract":"The paper presents the results of the study of the component composition of the reaction gases mixture when synthesizing carbonitride coatings of the Ti–Al–C–N system influencing the cutting tool durability. The coating was applied using the updated unit NNV-6.6-I1 by spraying from two one-component cathodes assisted by the incandescent cathode plasma source. During applying the coating, the mixture of reaction gases of N2 nitrogen and C2H2 acetylene in the ratio of 1:4, 2:3, 3:2, and 4:1 was delivered to the chamber. The paper presents the results of measuring the microhardness of studied specimens, which show that a sample with the coating deposited at the reaction gases ratio of N2:C2H2=2:3 had the largest microhardness value (4870 HV0.05). The paper presents the results of field tests of carbide-tipped tools with the studied coatings. Durability tests identified that a cutter with the coating deposited at the gas ratio of N2:C2H2=4:1 increases the tool durability ten times compared to a cutting tool without coating. Using the electron microscopy method, the authors investigated the chemical composition of the tool cutting face after tests. The analysis of the chemical composition of the surface after cutting showed that the content of coating elements on the surface of the sample with a coating deposited at the 4:1 ratio of the reaction gases of nitrogen and acetylene was considerably higher than that of other studied coatings, which indicates the less coating wear. However, ferrum is present in some areas of the cutting face, which says about the adhesion of treated material to the tool.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129515852","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 : 1900-01-01DOI: 10.18323/2782-4039-2022-2-84-91
A. Suslin, I. Barmanov
Worm gears are widely used in mechanical engineering. Recently, worm gears with a globoid worm attract a considerable interest. To improve the quality characteristics of globoid gears, their geometric dimensions and parameters, as well as the production technologies are being improved. It is also important to have a methodology for calculating the strength, which is, however, currently unavailable, and the state standards cover the issue of determining and calculating only the transmission geometry. In this regard, the development of the technique for calculating the contact and bending strength of a globoid worm gear appears relevant. The basic areas of the research are gear enhancement, production technology improvement, the gearing pattern study, working surfaces mathematical simulation, 3-D modeling, and the transmission calculation. The contact strength calculation is based on the Hertz’s formula taking into account the geometric features of globoid worm gears. The authors developed the calculation of the bending strength of the worm gear teeth based on the helical gear calculation method. The paper presents data on the influence of the mechanical properties of the materials of a worm and a worm gear wheel on the gear contact strength, gives the computed coefficients estimated values. The authors note that the dynamic load factor can increase significantly with the wear of the gear working surfaces. The research findings can be used to develop the design calculation technique, as well as to improve it to take into account the effect of transmission wear and working temperature on the operation duration.
{"title":"The technique for calculating the strength of a globoid worm gear","authors":"A. Suslin, I. Barmanov","doi":"10.18323/2782-4039-2022-2-84-91","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-2-84-91","url":null,"abstract":"Worm gears are widely used in mechanical engineering. Recently, worm gears with a globoid worm attract a considerable interest. To improve the quality characteristics of globoid gears, their geometric dimensions and parameters, as well as the production technologies are being improved. It is also important to have a methodology for calculating the strength, which is, however, currently unavailable, and the state standards cover the issue of determining and calculating only the transmission geometry. In this regard, the development of the technique for calculating the contact and bending strength of a globoid worm gear appears relevant. The basic areas of the research are gear enhancement, production technology improvement, the gearing pattern study, working surfaces mathematical simulation, 3-D modeling, and the transmission calculation. The contact strength calculation is based on the Hertz’s formula taking into account the geometric features of globoid worm gears. The authors developed the calculation of the bending strength of the worm gear teeth based on the helical gear calculation method. The paper presents data on the influence of the mechanical properties of the materials of a worm and a worm gear wheel on the gear contact strength, gives the computed coefficients estimated values. The authors note that the dynamic load factor can increase significantly with the wear of the gear working surfaces. The research findings can be used to develop the design calculation technique, as well as to improve it to take into account the effect of transmission wear and working temperature on the operation duration.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"55 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120835328","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 : 1900-01-01DOI: 10.18323/2782-4039-2023-2-64-2
A. Amosov, V. Novikov, E. M. Kachkin, N. Kryukov, A. Titov, I. Sosnin
The paper presents the results of a detailed study of the process and products of combustion during self-propagating high-temperature synthesis (SHS) of ZnO zinc oxide powder from mixtures of such common reagents as oxidizer zinc nitrate and reducing agent (fuel) glycine, as well as the application of synthesized highly dispersed submicron and nanosized ZnO powder for the phenol photocatalytic decomposition under the action of ultraviolet irradiation. An aqueous solution of a mixture of reagents (the SHS-S process or Solution Combustion Synthesis – SCS) and the gel from a mixture of initial dry reagents formed when they were moistened due to hygroscopicity (the SHS-G process or Gel Combustion Synthesis – GCS) were combusted. The authors studied the phase and chemical compositions, the structure of the combustion product, and the effect of calcination in an oxidizing air medium and grinding in drum ball and planetary-centrifugal mills, as well as in mortar, on them and their photocatalythic activity. The study showed that calcination considerably increases the photocatalytic activity of combustion products due to a significant decrease in carbon impurity in the unburned fuel remains, and grinding in mills reduces the photocatalytic activity due to iron contamination and coarsening of ZnO particle agglomerates. The difference between the photocatalytic activity of the SHS-G and SHS-S products in the phenol decomposition is evident only at the initial stage of ultraviolet irradiation, after which this difference disappears. The authors discuss the direction of further research to increase significantly the photocatalytic activity of zinc oxide synthesized during combustion to use it effectively for the phenol decomposition under the action of visible light.
{"title":"The formation of highly dispersed zinc oxide powder during combustion of zinc nitrate with glycine mixture and its application for photocatalytic phenol decomposition","authors":"A. Amosov, V. Novikov, E. M. Kachkin, N. Kryukov, A. Titov, I. Sosnin","doi":"10.18323/2782-4039-2023-2-64-2","DOIUrl":"https://doi.org/10.18323/2782-4039-2023-2-64-2","url":null,"abstract":"The paper presents the results of a detailed study of the process and products of combustion during self-propagating high-temperature synthesis (SHS) of ZnO zinc oxide powder from mixtures of such common reagents as oxidizer zinc nitrate and reducing agent (fuel) glycine, as well as the application of synthesized highly dispersed submicron and nanosized ZnO powder for the phenol photocatalytic decomposition under the action of ultraviolet irradiation. An aqueous solution of a mixture of reagents (the SHS-S process or Solution Combustion Synthesis – SCS) and the gel from a mixture of initial dry reagents formed when they were moistened due to hygroscopicity (the SHS-G process or Gel Combustion Synthesis – GCS) were combusted. The authors studied the phase and chemical compositions, the structure of the combustion product, and the effect of calcination in an oxidizing air medium and grinding in drum ball and planetary-centrifugal mills, as well as in mortar, on them and their photocatalythic activity. The study showed that calcination considerably increases the photocatalytic activity of combustion products due to a significant decrease in carbon impurity in the unburned fuel remains, and grinding in mills reduces the photocatalytic activity due to iron contamination and coarsening of ZnO particle agglomerates. The difference between the photocatalytic activity of the SHS-G and SHS-S products in the phenol decomposition is evident only at the initial stage of ultraviolet irradiation, after which this difference disappears. The authors discuss the direction of further research to increase significantly the photocatalytic activity of zinc oxide synthesized during combustion to use it effectively for the phenol decomposition under the action of visible light.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"344 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122448389","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 : 1900-01-01DOI: 10.18323/2782-4039-2022-3-1-61-68
V. A. Bryzgalov, S. Dmitriev, E. Korznikova, Yu. V. Bebikhov
The electro-plastic effect is a decrease in the resistance of metal crystals to deformation under the influence of a high-density pulsed electric current. Applying this effect allows deformation processing of relatively brittle metals without a sharp increase in temperature while reducing the probability of temperature negatively affecting the material. The paper discusses the influence of the electro-plastic effect on the change in the deforming force and the dislocations dynamics for a two-dimensional single crystal model based on the molecular dynamics method using the Morse potential. The authors propose a model implementing the electro-plastic effect by increasing the total kinetic energy of the system not uniformly over the entire crystal volume but depending on the potential energy of atoms. It is accepted that as a result of the electric current pulse traveling, the atom’s kinetic energy increases proportionally to the third degree of their potential energy. Atoms near defects have higher potential energy; therefore, the temperature will grow to a greater extent in the areas of defects, increasing their mobility. The authors simulated the motion of dislocations under the influence of shear stresses and temperature, considering the electric current pulse effect on the system. The paper describes the dependence of yield strength on temperature without taking into account the electro-plastic effect and then with it. The authors plotted the graphs of the dependence of the system’s kinetic energy on the frequency and the power of current pulses. The study shows that the electro-plastic effect sharply reduces the yield strength of a crystal, increasing the temperature in the system. It is caused by the fact that, besides general heating, the system is subjected to local heating of atoms near defects, which facilitates their motion.
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Pub Date : 1900-01-01DOI: 10.18323/2782-4039-2022-3-1-76-84
A. Kazakov, Yu. R. Sharapova, R. Babicheva, A. V. Zivovev, D. Terentyev, A. S. Semenov
Tungsten is widely used as a material capable of withstanding working conditions in nuclear reactors and other extreme conditions. Under the influence of irradiation, such defects as Frenkel pairs, pores, and dislocation loops are formed in the metal. Therefore, the research aimed at studying the interactions of these defects with each other and their influence on the mechanical properties of the metal are relevant. The paper presents the theoretical study based on the molecular dynamics method, the purpose of which is to investigate the mechanism of strain hardening of tungsten associated with the interaction of dislocations and pores. The authors solved this problem using the LAMMPS package, carried out the integration of atoms motion equations by the fourth order Verlet method. The model under the study is a single crystal of a certain [111], [–1–12], [1–10] orientation along the basic X, Y, and Z coordinate axis relatively, in which the slip of edge dislocations in the main slip system of BCC metals and their interaction with pores is considered. The authors studied the influence of a pore size on the shear stress magnitude: the growth of pore diameter is proportional to the stress growth. The dependences of shear stress on the shear strain in the temperature range of 600–1400 K are calculated, whereby the temperature change does not significantly influence the stress value. The study shows that dislocations cut the pores and, upon the repeated interaction with a pore, a lower value of peak shear stress is observed than during the first one. The presence of pores leads to the flow stress increase, and such an effect becomes more evident with the increasing pore diameter. The flow stress increases thrice for pores with a diameter of 6 nm compared to the material without pores. The authors described the mechanism of interaction between the edge dislocations and pores under the influence of shear stress.
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Pub Date : 1900-01-01DOI: 10.18323/2782-4039-2022-1-61-72
A. Rozen, I. L. Kharina, A. Gudenko, A. V. Pryshchak, A. V. Khorin, V. M. Batrashov, M. S. Guskov, A. A. Rozen, D. V. Kozlov
The paper presents the research on special aspects of structure formation in the transition zones of a layer metal material made of structural carbon and alloy stainless steels with an internal protector. The authors specify the order of layers arrangement. As an industrial method of producing such a material, the explosion welding technology was selected, which ensures the production of three-, four- and six-layer materials with one and two internal protectors per one explosion. The selection of optimal process parameters was carried out using computer modeling in the LS-DYNA software product. By calculation, the authors determined the main technological parameters of the process, which provide in the contact zone at each interlayer boundary the ratio of the amplitude of the generated waves to their length in the range from 0.3 to 0.5. Mechanical tests of multilayer workpieces were carried out. The shear strength of layers was from 320 to 410 MPa, the ultimate tensile strength of the main layer was from 520 to 710 MPa, the impact resistance was from 290 to 740 kJ/m2, and the bending angle under static loading was 140 degrees and higher. The authors determined the phase composition and characteristics of the crystallographic structure of transition zones of a layer metal material with an internal protector. The study identified the presence of γ-Fe with a face-centered crystal lattice, two cubic structures, one hexagonal, and one orthorhombic. On the samples with artificial pitting, the authors determined their influence on the rate of anodic dissolution of a protective layer when contacting with an aggressive environment. The study shows that the interlayer boundaries with a homogeneous structure and minimal thickness have the highest corrosion resistance.
{"title":"SPECIAL ASPECTS OF STRUCTURE FORMATION OF A TRANSITION ZONE IN A LAYER COMPOSITE PRODUCED BY EXPLOSION WELDING","authors":"A. Rozen, I. L. Kharina, A. Gudenko, A. V. Pryshchak, A. V. Khorin, V. M. Batrashov, M. S. Guskov, A. A. Rozen, D. V. Kozlov","doi":"10.18323/2782-4039-2022-1-61-72","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-1-61-72","url":null,"abstract":"The paper presents the research on special aspects of structure formation in the transition zones of a layer metal material made of structural carbon and alloy stainless steels with an internal protector. The authors specify the order of layers arrangement. As an industrial method of producing such a material, the explosion welding technology was selected, which ensures the production of three-, four- and six-layer materials with one and two internal protectors per one explosion. The selection of optimal process parameters was carried out using computer modeling in the LS-DYNA software product. By calculation, the authors determined the main technological parameters of the process, which provide in the contact zone at each interlayer boundary the ratio of the amplitude of the generated waves to their length in the range from 0.3 to 0.5. Mechanical tests of multilayer workpieces were carried out. The shear strength of layers was from 320 to 410 MPa, the ultimate tensile strength of the main layer was from 520 to 710 MPa, the impact resistance was from 290 to 740 kJ/m2, and the bending angle under static loading was 140 degrees and higher. The authors determined the phase composition and characteristics of the crystallographic structure of transition zones of a layer metal material with an internal protector. The study identified the presence of γ-Fe with a face-centered crystal lattice, two cubic structures, one hexagonal, and one orthorhombic. On the samples with artificial pitting, the authors determined their influence on the rate of anodic dissolution of a protective layer when contacting with an aggressive environment. The study shows that the interlayer boundaries with a homogeneous structure and minimal thickness have the highest corrosion resistance.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"159 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132374562","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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