Pub Date : 1900-01-01DOI: 10.18323/2782-4039-2023-2-64-7
V. Sitdikov, E. Khafizova, M. Polenok
In this paper, the authors consider the mechanisms of formation of high-strength states in the Zn–1%Li–2%Mg alloy as a result of its processing by the high pressure torsion (HPT) method. For the first time, the study showed that using HPT treatment, as a result of varying the degree of deformation at room temperature, it is possible to increase the ultimate strength of a zinc alloy from 155 to 383 MPa (with an increase in the yield stress from 149 to 306 MPa) without losing its ductility. To explain the reasons for the increase in the zinc alloy mechanical properties, its microstructure was analyzed by scanning electron microscopy (SEM), X-ray phase analysis (XPA), X-ray diffraction analysis (XRD), and small-angle X-ray scattering (SAXS). Using XPA, the authors established for the first time that Zn(eutectic)+β-LiZn4(eutectic)→~LiZn3+Zn(phase)+Zn(precipitation) and MgZn2→Mg2Zn11 phase transformations occur in the zinc alloy during HPT treatment. SEM analysis showed that at the initial stages of HPT treatment, cylindrical Zn particles with a diameter of 330 nm and a length of up to 950 nm precipitate in β-LiZn3 phase. At the same time, the SAXS method showed that needle-like LiZn4 particles with a diameter of 9 nm and a length of 28 nm precipitate in the Zn phase. The study established that, only spherical Zn and LiZn4 particles precipitate at high degrees of HPT treatment. Precision analysis of the zinc alloy microstructure showed that HPT treatment leads to grain refinement, an increase in the magnitude of crystal lattice microdistortion, a growth of the density of dislocations, which are predominantly of the edge type. As a result of the analysis of hardening mechanisms, the authors concluded that the increase in the zinc alloy strength characteristics mainly occurs due to grain-boundary, dislocation, and dispersion hardening.
{"title":"Microstructure and properties of the Zn–1%Li–2%Mg alloy subjected to severe plastic deformation","authors":"V. Sitdikov, E. Khafizova, M. Polenok","doi":"10.18323/2782-4039-2023-2-64-7","DOIUrl":"https://doi.org/10.18323/2782-4039-2023-2-64-7","url":null,"abstract":"In this paper, the authors consider the mechanisms of formation of high-strength states in the Zn–1%Li–2%Mg alloy as a result of its processing by the high pressure torsion (HPT) method. For the first time, the study showed that using HPT treatment, as a result of varying the degree of deformation at room temperature, it is possible to increase the ultimate strength of a zinc alloy from 155 to 383 MPa (with an increase in the yield stress from 149 to 306 MPa) without losing its ductility. To explain the reasons for the increase in the zinc alloy mechanical properties, its microstructure was analyzed by scanning electron microscopy (SEM), X-ray phase analysis (XPA), X-ray diffraction analysis (XRD), and small-angle X-ray scattering (SAXS). Using XPA, the authors established for the first time that Zn(eutectic)+β-LiZn4(eutectic)→~LiZn3+Zn(phase)+Zn(precipitation) and MgZn2→Mg2Zn11 phase transformations occur in the zinc alloy during HPT treatment. SEM analysis showed that at the initial stages of HPT treatment, cylindrical Zn particles with a diameter of 330 nm and a length of up to 950 nm precipitate in β-LiZn3 phase. At the same time, the SAXS method showed that needle-like LiZn4 particles with a diameter of 9 nm and a length of 28 nm precipitate in the Zn phase. The study established that, only spherical Zn and LiZn4 particles precipitate at high degrees of HPT treatment. Precision analysis of the zinc alloy microstructure showed that HPT treatment leads to grain refinement, an increase in the magnitude of crystal lattice microdistortion, a growth of the density of dislocations, which are predominantly of the edge type. As a result of the analysis of hardening mechanisms, the authors concluded that the increase in the zinc alloy strength characteristics mainly occurs due to grain-boundary, dislocation, and dispersion hardening.","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":"130768525","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: 10.18323/2782-4039-2023-1-7-21
F. Bao, O. Bashkov, Dan Zhang, Lan Lyu, T. Bashkova
An effective way to protect valve metals and their alloys is the micro-arc oxidation method (MAO), which is currently used in various industries. However, to achieve the desired characteristics and properties of oxide coatings, a large number of experiments are required to determine an optimal oxidation mode, which makes the MAO method labor-intensive and resource-consuming. One of the ways to solve this problem is the search for an informative parameter or several parameters, the use of which during the oxidation process monitoring allows identifying a relationship between the MAO modes and the specified characteristics of oxide coatings. This paper studies the influence of the specified technological MAO modes (current density, oxidation time, amplitude of acoustic emission (AE) signals recorded during MAO) on the morphology and parameters of oxide coatings (thickness δ and surface roughness Ra) deposited on the D16AT aluminum alloy clad with pure aluminum. Multivariate planning of an experiment and the performed regression analysis allowed establishing a relationship between two oxidation factors (current density and oxidation time) and the parameters of the produced coatings. The authors proposed an additional factor, which is determined in the monitoring mode during the oxidation process as the time from the moment when the maximum or minimum of the acoustic emission (AE) amplitude recorded in the MAO process is reached until the end of the oxidation process. The study established that the introduction of an additional factor allows increasing significantly the reliability of the dependence between the coating parameters obtained experimentally and by the computational method based on the regression analysis. The authors note that when performing MAO, with the additional use of the MAO process monitoring by recording the AE amplitude, it is possible to achieve a high reliability between the calculated and actual values of the parameters of oxide coatings.
{"title":"The study of the influence of micro-arc oxidation modes on the morphology and parameters of an oxide coating on the D16AT aluminum alloy","authors":"F. Bao, O. Bashkov, Dan Zhang, Lan Lyu, T. Bashkova","doi":"10.18323/2782-4039-2023-1-7-21","DOIUrl":"https://doi.org/10.18323/2782-4039-2023-1-7-21","url":null,"abstract":"An effective way to protect valve metals and their alloys is the micro-arc oxidation method (MAO), which is currently used in various industries. However, to achieve the desired characteristics and properties of oxide coatings, a large number of experiments are required to determine an optimal oxidation mode, which makes the MAO method labor-intensive and resource-consuming. One of the ways to solve this problem is the search for an informative parameter or several parameters, the use of which during the oxidation process monitoring allows identifying a relationship between the MAO modes and the specified characteristics of oxide coatings. This paper studies the influence of the specified technological MAO modes (current density, oxidation time, amplitude of acoustic emission (AE) signals recorded during MAO) on the morphology and parameters of oxide coatings (thickness δ and surface roughness Ra) deposited on the D16AT aluminum alloy clad with pure aluminum. Multivariate planning of an experiment and the performed regression analysis allowed establishing a relationship between two oxidation factors (current density and oxidation time) and the parameters of the produced coatings. The authors proposed an additional factor, which is determined in the monitoring mode during the oxidation process as the time from the moment when the maximum or minimum of the acoustic emission (AE) amplitude recorded in the MAO process is reached until the end of the oxidation process. The study established that the introduction of an additional factor allows increasing significantly the reliability of the dependence between the coating parameters obtained experimentally and by the computational method based on the regression analysis. The authors note that when performing MAO, with the additional use of the MAO process monitoring by recording the AE amplitude, it is possible to achieve a high reliability between the calculated and actual values of the parameters of oxide coatings.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"153 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":"126889437","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: 10.18323/2782-4039-2022-2-28-36
V. V. Kaminskii, D. A. Kalganov, E. Podlesnov, A. Romanov
Magnetic shape memory alloys are a specific subtype of shape memory materials. The magnetic deformation phenomenon causes the high research interest in these alloys. Thus, in one of the most promising alloys based on Ni–Mn–Ga, using a magnetic field, it is possible to achieve changes in a single crystal size by up to 10 % due to the reorientation of the magnetic field in magnetic domains. The high magnetic deformation is directly related to the high mobility of twin boundaries separating two domains. In this work, the authors used a composite piezoelectric oscillator at a frequency of about 100 kHz to determine the influence of such defects as dislocations and twin boundaries on the mechanical characteristics of Ni49Mn30Ga21. The authors investigated the features of temperature dependences of internal friction in the samples before and after deformation and provided the amplitude dependences of these characteristics. In the studied single-crystal martensitic phase, the transition from the tetragonal phase to the orthorhombic phase was detected at 235 K. In the Ni–Mn–Ga tetragonal phase, the formation of new defects contributes to the more pronounced and early onset of amplitude-dependent internal friction. At lower loads, the successive stages occur associated with the processes of dislocations and twin boundaries movements inside the Cottrell clouds, dislocations and twin boundaries movement outside the Cottrell clouds, and supposedly, the slowdown of dislocations and twin boundaries movement due to their interaction. As well as internal friction, the authors studied the change in Young’s modulus. Its decrease at all temperatures is most pronounced in the samples with the defective structures. The study identified that in the orthorhombic phase, it is possible to observe the internal friction dependence on the deformation amplitude at a lower load due to an increase in the twin boundaries mobility with increasing temperature.
{"title":"The influence of dislocation and twin structures on the mechanical characteristics of Ni–Mn–Ga alloys at ultrasonic frequencies","authors":"V. V. Kaminskii, D. A. Kalganov, E. Podlesnov, A. Romanov","doi":"10.18323/2782-4039-2022-2-28-36","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-2-28-36","url":null,"abstract":"Magnetic shape memory alloys are a specific subtype of shape memory materials. The magnetic deformation phenomenon causes the high research interest in these alloys. Thus, in one of the most promising alloys based on Ni–Mn–Ga, using a magnetic field, it is possible to achieve changes in a single crystal size by up to 10 % due to the reorientation of the magnetic field in magnetic domains. The high magnetic deformation is directly related to the high mobility of twin boundaries separating two domains. In this work, the authors used a composite piezoelectric oscillator at a frequency of about 100 kHz to determine the influence of such defects as dislocations and twin boundaries on the mechanical characteristics of Ni49Mn30Ga21. The authors investigated the features of temperature dependences of internal friction in the samples before and after deformation and provided the amplitude dependences of these characteristics. In the studied single-crystal martensitic phase, the transition from the tetragonal phase to the orthorhombic phase was detected at 235 K. In the Ni–Mn–Ga tetragonal phase, the formation of new defects contributes to the more pronounced and early onset of amplitude-dependent internal friction. At lower loads, the successive stages occur associated with the processes of dislocations and twin boundaries movements inside the Cottrell clouds, dislocations and twin boundaries movement outside the Cottrell clouds, and supposedly, the slowdown of dislocations and twin boundaries movement due to their interaction. As well as internal friction, the authors studied the change in Young’s modulus. Its decrease at all temperatures is most pronounced in the samples with the defective structures. The study identified that in the orthorhombic phase, it is possible to observe the internal friction dependence on the deformation amplitude at a lower load due to an increase in the twin boundaries mobility with increasing temperature.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"42 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":"124822589","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: 10.18323/2782-4039-2022-3-2-90-98
A. Khalikov, Yu. V. Bebikhov, E. Korznikova, S. Dmitriev
Planar superstructural defects have a great influence on the mechanical, functional properties of binary ordered alloys of the L10 superstructure based on the fcc lattice, but there is no complete analysis of their structure and energy in the literature. For the L10 superstructure alloys of the stoichiometric composition AB, the paper gives the expressions for calculating the sublimation energy and the energy of a planar superstructural defect in the model of hard coordination spheres and pair interatomic interactions. The crystal lattice tetragonality was not taken into account. The authors presented the ordered alloy structure as a union of four monoatomic simple cubic lattices, two of which are occupied by A atoms, and the other two by B atoms. This approach allows calculating the sublimation energy required for crystal evaporation. The first eight coordination spheres were taken into account in the work. The paper shows an algorithm for determining all possible geometrically different representations of the L10 superstructure with the same sublimation energy, gives an expression for finding the planes of occurrence of all possible conservative antiphase boundaries. The study identified that the conservative and nonconservative antiphase boundaries, as well as conservative and nonconservative boundaries of C-domains are observed in the binary ordered alloys of the L10 superstructure based on the fcc lattice. The algorithms described in this work make it possible to carry out a crystal-geometric analysis of planar defects in both binary and multicomponent ordered alloys with various superstructures.
{"title":"Planar superstructural defects in the alloys with L10 superstructure","authors":"A. Khalikov, Yu. V. Bebikhov, E. Korznikova, S. Dmitriev","doi":"10.18323/2782-4039-2022-3-2-90-98","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-3-2-90-98","url":null,"abstract":"Planar superstructural defects have a great influence on the mechanical, functional properties of binary ordered alloys of the L10 superstructure based on the fcc lattice, but there is no complete analysis of their structure and energy in the literature. For the L10 superstructure alloys of the stoichiometric composition AB, the paper gives the expressions for calculating the sublimation energy and the energy of a planar superstructural defect in the model of hard coordination spheres and pair interatomic interactions. The crystal lattice tetragonality was not taken into account. The authors presented the ordered alloy structure as a union of four monoatomic simple cubic lattices, two of which are occupied by A atoms, and the other two by B atoms. This approach allows calculating the sublimation energy required for crystal evaporation. The first eight coordination spheres were taken into account in the work. The paper shows an algorithm for determining all possible geometrically different representations of the L10 superstructure with the same sublimation energy, gives an expression for finding the planes of occurrence of all possible conservative antiphase boundaries. The study identified that the conservative and nonconservative antiphase boundaries, as well as conservative and nonconservative boundaries of C-domains are observed in the binary ordered alloys of the L10 superstructure based on the fcc lattice. The algorithms described in this work make it possible to carry out a crystal-geometric analysis of planar defects in both binary and multicomponent ordered alloys with various superstructures.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"73 32","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134196965","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: 10.18323/2782-4039-2022-1-7-14
L. Almazova, O. Sedova
Aluminum and its alloys, such as the Al–Si–Mg alloy, are widely used in various industrial and engineering fields due to their mechanical properties. In this case, the defects occurring during the casting process adversely affect the behavior of this alloy under cyclic load conditions. Therefore, the study aimed to investigate the surface defect influence on the material's fatigue strength is currently of great importance. The paper presents a numerical investigation based on the finite element method intended to evaluate the effect of the interaction of the complex-shaped defects on the stress of the Al–Si–Mg aluminum alloy. The developed complex-defect model consists of a hemispherical main (base) defect and a secondary defect at the bottom of the main one. The authors use the Chaboche model to describe the material’s behavior under the cyclic load conditions. The paper contains the computational solution constructed with the ANSYS Workbench platform. The authors supposed that it is possible to approximate the considered complex defect form by an equivalent simplified defect. The study shows that the maximum von Mises stress values for the complex-shaped defects are achieved at the joint of the secondary defect with the main one. In the case of an equivalent defect, the maximum values are observed at the defect's bottom and on the periphery. The authors comparatively estimated the uncertainty obtained using an equivalent defect and the cases of three complex-shaped defects and three hemispherical defects without additional (secondary) damage. This estimation shows that in the case of a complex-shaped defect, the equivalent defect model has an error of 14.5 %, which is 6.5 % greater than in the case of the hemispherical defects without secondary damages at the bottom.
{"title":"SIMULATION OF THE SURFACE DEFECTS INFLUENCE ON THE ALUMINUM ALLOY BEHAVIOUR UNDER THE CYCLIC LOAD CONDITIONS","authors":"L. Almazova, O. Sedova","doi":"10.18323/2782-4039-2022-1-7-14","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-1-7-14","url":null,"abstract":"Aluminum and its alloys, such as the Al–Si–Mg alloy, are widely used in various industrial and engineering fields due to their mechanical properties. In this case, the defects occurring during the casting process adversely affect the behavior of this alloy under cyclic load conditions. Therefore, the study aimed to investigate the surface defect influence on the material's fatigue strength is currently of great importance. The paper presents a numerical investigation based on the finite element method intended to evaluate the effect of the interaction of the complex-shaped defects on the stress of the Al–Si–Mg aluminum alloy. The developed complex-defect model consists of a hemispherical main (base) defect and a secondary defect at the bottom of the main one. The authors use the Chaboche model to describe the material’s behavior under the cyclic load conditions. The paper contains the computational solution constructed with the ANSYS Workbench platform. The authors supposed that it is possible to approximate the considered complex defect form by an equivalent simplified defect. The study shows that the maximum von Mises stress values for the complex-shaped defects are achieved at the joint of the secondary defect with the main one. In the case of an equivalent defect, the maximum values are observed at the defect's bottom and on the periphery. The authors comparatively estimated the uncertainty obtained using an equivalent defect and the cases of three complex-shaped defects and three hemispherical defects without additional (secondary) damage. This estimation shows that in the case of a complex-shaped defect, the equivalent defect model has an error of 14.5 %, which is 6.5 % greater than in the case of the hemispherical defects without secondary damages at the bottom.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"111 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":"132482059","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: 10.18323/2782-4039-2022-3-1-50-60
V. Atroshchenko, A. S. Selivanov, V. S. Lobachev, Yu. V. Logachev, A. R. Sadrislamov
Copper is widely used when producing current-conducting parts, basically the electrotechnical power equipment buses. Traditional ways of welding copper become complicated because of high thermal conductivity, fluidity, significant oxidation at fusing temperature, and susceptibility. The application of the solid-phase welding methods, a prominent representative of which is friction stir welding (FSW), is one of the ways to solve problems when welding copper. The paper presents the experimental study of the influence of a tool working part shape and the welding mode parameters: welding rate, tool rotation frequency, and tool dip angle – on the possibility of the appearance of defects in welded joints of M1 copper plates of 5 mm in thickness produced by FSW. The paper contains the results of mechanical tests on static tension and bending of welded joints with a tunnel defect and without it. Welded joints with a tunnel defect showed a decrease in mechanical properties level: the value of ultimate tensile strength at stretching is lower by 33 %, and the specific elongation is lower by 8 % than ones of a joint without defects. The authors specify some factors influencing the appearance of defects at FSW: the welding rate, tool rotation frequency, tool working part construction, tool dip angle, strength and depth of immersion, pin displacement, blank thickness, and grip conditions. The study identified that the application of a tool with a concave surface taper shoulder allows producing welded joints without external and internal defects. Based on data obtained during the experimental research, the authors determined the welding modes, which makes it possible to produce welded joints with the electrical resistance value at the level of a parent metal: tool rotation frequency is 1250 rpm, welding rate is 25 mm/min, and tool immersion depth is no less than 0.41 mm.
{"title":"The study of the effect of parameters of the mode of copper friction stir welding on the mechanical properties and electrical conductivity of welded joints","authors":"V. Atroshchenko, A. S. Selivanov, V. S. Lobachev, Yu. V. Logachev, A. R. Sadrislamov","doi":"10.18323/2782-4039-2022-3-1-50-60","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-3-1-50-60","url":null,"abstract":"Copper is widely used when producing current-conducting parts, basically the electrotechnical power equipment buses. Traditional ways of welding copper become complicated because of high thermal conductivity, fluidity, significant oxidation at fusing temperature, and susceptibility. The application of the solid-phase welding methods, a prominent representative of which is friction stir welding (FSW), is one of the ways to solve problems when welding copper. The paper presents the experimental study of the influence of a tool working part shape and the welding mode parameters: welding rate, tool rotation frequency, and tool dip angle – on the possibility of the appearance of defects in welded joints of M1 copper plates of 5 mm in thickness produced by FSW. The paper contains the results of mechanical tests on static tension and bending of welded joints with a tunnel defect and without it. Welded joints with a tunnel defect showed a decrease in mechanical properties level: the value of ultimate tensile strength at stretching is lower by 33 %, and the specific elongation is lower by 8 % than ones of a joint without defects. The authors specify some factors influencing the appearance of defects at FSW: the welding rate, tool rotation frequency, tool working part construction, tool dip angle, strength and depth of immersion, pin displacement, blank thickness, and grip conditions. The study identified that the application of a tool with a concave surface taper shoulder allows producing welded joints without external and internal defects. Based on data obtained during the experimental research, the authors determined the welding modes, which makes it possible to produce welded joints with the electrical resistance value at the level of a parent metal: tool rotation frequency is 1250 rpm, welding rate is 25 mm/min, and tool immersion depth is no less than 0.41 mm.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"343 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":"124234693","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: 10.18323/2782-4039-2023-2-64-6
O. Novikova, A. Kostina, Yu. A. Salamatov, D. A. Zgibnev, A. Volkov
Due to low electrical resistivity, the Cu–Pd and Cu–Pd–Ag system alloys can be used as corrosion-resistant conductors of weak electrical signals. The paper deals with a comparison of the structure and physical-mechanical properties of Cu, Cu–3Pd and Cu–3Pd–3Ag (at. %) alloys after deformation at room or cryogenic temperature followed by annealing. The authors studied specimens in different initial states: quenched, deformed at room and cryogenic temperatures. To study the processes of structure rearrangement and the evolution of properties, annealing was carried out in the temperature range from 100 to 450 °C, followed by cooling in water. The duration of heat treatments was 1 h. The dependences of the yield strength and elongation to failure on the annealing temperature showed that cryodeformation significantly increases the thermal stability of the structure of both pure copper and the Cu–3Pd–3Ag ternary alloy. According to the temperature dependence of specific electrical resistivity of the deformed Cu–3Pd–3Ag alloy during heating at a rate of 120 deg./h, it was found that the decrease in electrical resistance caused by recrystallization begins at above 300 °C. The dependences of specific electrical resistivity on true strain showed that the structure rearrangement mechanisms during deformation are different for pure copper and the Cu–3Pd–3Ag alloy. The results of mathematical processing of the peaks in the diffraction patterns established that two phases appear in the Cu–3Pd–3Ag alloy after cryodeformation and annealing, one of which is silver-enriched, and the other is depleted. The study showed that during annealing of the deformed (especially after cryodeformation) Cu–3Pd–3Ag alloy, an anomalous increase in strength properties is observed. It was identified that alloying copper with palladium and silver leads to an increase in the recrystallization temperature. Thus, copper alloys with small palladium and silver additives are obviously attractive for practical applications, since they have improved strength properties, satisfactory electrical conductivity, and a higher recrystallization temperature compared to pure copper.
{"title":"The influence of deformation at cryogenic or room temperature followed by annealing on the structure and properties of copper and its Cu–3Pd and Cu–3Pd–3Ag (at. %) alloys","authors":"O. Novikova, A. Kostina, Yu. A. Salamatov, D. A. Zgibnev, A. Volkov","doi":"10.18323/2782-4039-2023-2-64-6","DOIUrl":"https://doi.org/10.18323/2782-4039-2023-2-64-6","url":null,"abstract":"Due to low electrical resistivity, the Cu–Pd and Cu–Pd–Ag system alloys can be used as corrosion-resistant conductors of weak electrical signals. The paper deals with a comparison of the structure and physical-mechanical properties of Cu, Cu–3Pd and Cu–3Pd–3Ag (at. %) alloys after deformation at room or cryogenic temperature followed by annealing. The authors studied specimens in different initial states: quenched, deformed at room and cryogenic temperatures. To study the processes of structure rearrangement and the evolution of properties, annealing was carried out in the temperature range from 100 to 450 °C, followed by cooling in water. The duration of heat treatments was 1 h. The dependences of the yield strength and elongation to failure on the annealing temperature showed that cryodeformation significantly increases the thermal stability of the structure of both pure copper and the Cu–3Pd–3Ag ternary alloy. According to the temperature dependence of specific electrical resistivity of the deformed Cu–3Pd–3Ag alloy during heating at a rate of 120 deg./h, it was found that the decrease in electrical resistance caused by recrystallization begins at above 300 °C. The dependences of specific electrical resistivity on true strain showed that the structure rearrangement mechanisms during deformation are different for pure copper and the Cu–3Pd–3Ag alloy. The results of mathematical processing of the peaks in the diffraction patterns established that two phases appear in the Cu–3Pd–3Ag alloy after cryodeformation and annealing, one of which is silver-enriched, and the other is depleted. The study showed that during annealing of the deformed (especially after cryodeformation) Cu–3Pd–3Ag alloy, an anomalous increase in strength properties is observed. It was identified that alloying copper with palladium and silver leads to an increase in the recrystallization temperature. Thus, copper alloys with small palladium and silver additives are obviously attractive for practical applications, since they have improved strength properties, satisfactory electrical conductivity, and a higher recrystallization temperature compared to pure copper.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"53 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":"128482057","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: 10.18323/2782-4039-2023-2-64-5
D. Tarov, D. A. Evlakhin, A. Zelenin, R. Stolyarov, V. Yagubov, N. Memetov, A. Memetova, N. Chapaksov, A. Gerasimova
In the modern literature, there are practically no data on the electrical characteristics of bituminous binders modified with carbon nanotubes and graphene nanoplates, while they are necessary for the design and development of innovative asphalt pavement compositions sensitive to the super-high-frequency microwave radiation. Contemporary bituminous binders are multi-component systems that may contain polymers, rubbers, synthetic or natural resins, inorganic salts, and even fragrances. As a result of application of modifying additives, bitumen acquires high performance characteristics. A special class of modifiers are micro- and nano-sized electrically conductive fibers and particles (steel wool, carbon fibers, carbon black, carbon nanotubes, graphene nanoplates), the use of which makes it possible to ensure the sensibility of bituminous binders to super-high-frequency microwave radiation and the implementation of the process of healing cracks in an asphalt pavement with its subsequent regeneration. As part of the study, the authors developed an original technique to produce bituminous binders modified with carbon nanotubes and multilayer graphene. Modified bituminous compositions in the concentration range from 0.2 to 6 and from 0.2 to 11 wt. % for multi-walled carbon nanotubes (MWCNT) and multilayer graphene nanoplates (MG), respectively were experimentally obtained. For the first time, the dependence of the specific volume electrical conductivity of bitumen-based nanocomposites on the concentration of nanostructured carbon filler (MWCNT and MG) was researched. The maximum values of electrical conductivity were 4.76×10−4 S/cm and 3.5×10−4 S/cm for nanocomposites containing 6 wt. % MWCNT and 11 wt. % MG, respectively. The study determined the filler volume fractions at the percolation threshold for nanocomposites containing MWCNT and MG. They amounted to 0.22 and 2.18, respectively. The formation of a percolation contour in nanocomposites containing MWCNT occurs at significantly lower filler concentrations compared to bituminous compositions containing MG.
{"title":"Electrically conductive nanocomposite bituminous binders containing carbon nanotubes and multilayer graphene","authors":"D. Tarov, D. A. Evlakhin, A. Zelenin, R. Stolyarov, V. Yagubov, N. Memetov, A. Memetova, N. Chapaksov, A. Gerasimova","doi":"10.18323/2782-4039-2023-2-64-5","DOIUrl":"https://doi.org/10.18323/2782-4039-2023-2-64-5","url":null,"abstract":"In the modern literature, there are practically no data on the electrical characteristics of bituminous binders modified with carbon nanotubes and graphene nanoplates, while they are necessary for the design and development of innovative asphalt pavement compositions sensitive to the super-high-frequency microwave radiation. Contemporary bituminous binders are multi-component systems that may contain polymers, rubbers, synthetic or natural resins, inorganic salts, and even fragrances. As a result of application of modifying additives, bitumen acquires high performance characteristics. A special class of modifiers are micro- and nano-sized electrically conductive fibers and particles (steel wool, carbon fibers, carbon black, carbon nanotubes, graphene nanoplates), the use of which makes it possible to ensure the sensibility of bituminous binders to super-high-frequency microwave radiation and the implementation of the process of healing cracks in an asphalt pavement with its subsequent regeneration. As part of the study, the authors developed an original technique to produce bituminous binders modified with carbon nanotubes and multilayer graphene. Modified bituminous compositions in the concentration range from 0.2 to 6 and from 0.2 to 11 wt. % for multi-walled carbon nanotubes (MWCNT) and multilayer graphene nanoplates (MG), respectively were experimentally obtained. For the first time, the dependence of the specific volume electrical conductivity of bitumen-based nanocomposites on the concentration of nanostructured carbon filler (MWCNT and MG) was researched. The maximum values of electrical conductivity were 4.76×10−4 S/cm and 3.5×10−4 S/cm for nanocomposites containing 6 wt. % MWCNT and 11 wt. % MG, respectively. The study determined the filler volume fractions at the percolation threshold for nanocomposites containing MWCNT and MG. They amounted to 0.22 and 2.18, respectively. The formation of a percolation contour in nanocomposites containing MWCNT occurs at significantly lower filler concentrations compared to bituminous compositions containing MG.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"63 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":"126444920","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: 10.18323/2782-4039-2022-3-1-85-95
A. V. Kapustin, N. Enikeev
Nowadays, to improve the quality of life, dental implantation is widely used, and ensuring proper functioning and durability of the implantable devices is one of the most crucial tasks for modern-day dentistry. The development of new biomaterials with improved properties, such as nanostructured materials, widens the possibilities of medical goods miniaturization to create new-generation implants. Computer simulation plays a large part when designing these devices, which allows effectively specifying an implant design depending on the materials used and operation conditions. This paper presents the results of modeling using the finite-element method for the comparative analysis of an implant’s deformed behavior within the cyclic load conditions. The authors considered large-grained commercially pure titanium and nanostructured titanium with improved properties as implant material. The authors analyzed various arrangements of an implanted device according to the fatigue testing conditions – considering and not considering the influence of an abutment and the base reaction. The study identified the implant’s characteristics, such as fatigue endurance and safety factor for a specific type of arrangement and material type, as well as the equivalent stress distribution, including taking into account a sign. The research shows that the most realistic results can be achieved when modeling a device in the “abutment – implant – base” arrangement. The study demonstrates that strength characteristics crucial for product destruction are described by the maximum principal stresses, and the studied implant configuration ensures its longstanding proper functioning in the case of its production exceptionally from nanostructured titanium with enhanced properties.
{"title":"Finite-element simulation of fatigue behavior of a medical implant produced from titanium in the large-grained and nanostructured states","authors":"A. V. Kapustin, N. Enikeev","doi":"10.18323/2782-4039-2022-3-1-85-95","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-3-1-85-95","url":null,"abstract":"Nowadays, to improve the quality of life, dental implantation is widely used, and ensuring proper functioning and durability of the implantable devices is one of the most crucial tasks for modern-day dentistry. The development of new biomaterials with improved properties, such as nanostructured materials, widens the possibilities of medical goods miniaturization to create new-generation implants. Computer simulation plays a large part when designing these devices, which allows effectively specifying an implant design depending on the materials used and operation conditions. This paper presents the results of modeling using the finite-element method for the comparative analysis of an implant’s deformed behavior within the cyclic load conditions. The authors considered large-grained commercially pure titanium and nanostructured titanium with improved properties as implant material. The authors analyzed various arrangements of an implanted device according to the fatigue testing conditions – considering and not considering the influence of an abutment and the base reaction. The study identified the implant’s characteristics, such as fatigue endurance and safety factor for a specific type of arrangement and material type, as well as the equivalent stress distribution, including taking into account a sign. The research shows that the most realistic results can be achieved when modeling a device in the “abutment – implant – base” arrangement. The study demonstrates that strength characteristics crucial for product destruction are described by the maximum principal stresses, and the studied implant configuration ensures its longstanding proper functioning in the case of its production exceptionally from nanostructured titanium with enhanced properties.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"16 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":"114182073","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: 10.18323/2782-4039-2022-3-2-44-55
V. Sitdikov, O. Kulyasova, G. Sitdikova, R. Islamgaliev, Yu. Zheng
In this paper, using the X-ray scattering method, the authors found the similaritues and differences in the structural-phase transformations in a Zn–Li–Mg alloy under the artificial and dynamic aging. The artificial aging (AA) of the alloy was implemented at a temperature of 300 ºС for 24 h, while the dynamic aging (DA) was performed through high-pressure torsion at room temperature for a few minutes. For the first time, using X-ray phase analysis, the authors identified the type and parameters of the LiZn2 phase crystal lattice (Pmmm, a=0.48635 nm, b=1.11021 nm, c=0.43719 nm, α=β=γ=90º) and the β-LiZn4 phase (P63/mmc, a=b=0.279868 nm, c=0.438598 nm, α=β=90º, γ=120º) to the eutectics in specified conditions. The study found that SPD leads to intensive precipitation of Zn particles in the primary β-LiZn4 phase, and β-LiZn4 particles precipitation in the Zn eutectics phase. While analyzing the diffraction patterns, the authors estimated the lattice parameter, the size distribution of coherent scattering regions, the averaged dislocation density, and the fraction of edge and screw dislocations after AA and DA. For the first time, by small-angle X-ray scattering, the authors identified the quantitative characteristics of the size, shape, and nature of the bimodal precipitate distribution in the above-mentioned conditions. In particular, it was found that fine Zn precipitates in the form of needles of 8 nm in diameter and up to 27 nm in length and coarse Zn precipitates in the form of rods of 460 nm in diameter and up to 1000 nm in length are produced in the alloy after AA. In the case of DA, fine Zn precipitates of a primarily spherical shape with an average diameter of 20 nm and coarse Zn precipitates, which formed in the primary β-LiZn4 phase a network with a cell diameter of 200–300 nm and wall thickness of 62 nm are produced in the Zn–Li–Mg alloy.
{"title":"Structural-phase transformations in the Zn–Li–Mg alloy exposed to the severe plastic torsion deformation","authors":"V. Sitdikov, O. Kulyasova, G. Sitdikova, R. Islamgaliev, Yu. Zheng","doi":"10.18323/2782-4039-2022-3-2-44-55","DOIUrl":"https://doi.org/10.18323/2782-4039-2022-3-2-44-55","url":null,"abstract":"In this paper, using the X-ray scattering method, the authors found the similaritues and differences in the structural-phase transformations in a Zn–Li–Mg alloy under the artificial and dynamic aging. The artificial aging (AA) of the alloy was implemented at a temperature of 300 ºС for 24 h, while the dynamic aging (DA) was performed through high-pressure torsion at room temperature for a few minutes. For the first time, using X-ray phase analysis, the authors identified the type and parameters of the LiZn2 phase crystal lattice (Pmmm, a=0.48635 nm, b=1.11021 nm, c=0.43719 nm, α=β=γ=90º) and the β-LiZn4 phase (P63/mmc, a=b=0.279868 nm, c=0.438598 nm, α=β=90º, γ=120º) to the eutectics in specified conditions. The study found that SPD leads to intensive precipitation of Zn particles in the primary β-LiZn4 phase, and β-LiZn4 particles precipitation in the Zn eutectics phase. While analyzing the diffraction patterns, the authors estimated the lattice parameter, the size distribution of coherent scattering regions, the averaged dislocation density, and the fraction of edge and screw dislocations after AA and DA. For the first time, by small-angle X-ray scattering, the authors identified the quantitative characteristics of the size, shape, and nature of the bimodal precipitate distribution in the above-mentioned conditions. In particular, it was found that fine Zn precipitates in the form of needles of 8 nm in diameter and up to 27 nm in length and coarse Zn precipitates in the form of rods of 460 nm in diameter and up to 1000 nm in length are produced in the alloy after AA. In the case of DA, fine Zn precipitates of a primarily spherical shape with an average diameter of 20 nm and coarse Zn precipitates, which formed in the primary β-LiZn4 phase a network with a cell diameter of 200–300 nm and wall thickness of 62 nm are produced in the Zn–Li–Mg alloy.","PeriodicalId":251458,"journal":{"name":"Frontier materials & technologies","volume":"26 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":"125467371","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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