№4 2021
Materials science
Thermomechanical behavior of functional composite material based on low density polyethylene reinforced with titanium nickel
D.E. Gusev, M.Yu. Kollerov, E.A. Lukina, R.E. Vinogradov, D.V. Burdin
Deformation and thermal characteristics of shape memory effect of composite material based on low density polyethylene (LDPE) matrix reinforced by NiTi wires have been analyzed at bending tests. Critical strain (ecr0,2) denoted as the total induced strain resulting in 0.2% of unrecovered strain upon unloading and heating and corresponding recovery start and finish temperatures (Аsf and Аfr) are suggested for the characterization of SME in these materials. It has been revealed that ecr0,2 of LDPE- NiTi composite is 6,0%, whereas ecr0,2 of NiTi wires having ecr0,2 = 9,0%. The thermal characteristics of the SME of the composite material and titanium nickelide wire are similar.
Keywords: NiTi alloy, shape memory composite, polymer matrix, low density polyethylene, critical strain, shape recovery temperatures, bending tests.
Estimation of absorbed energy in compression tests of titanium cellular structures of additive manufacturing
Y.N. Loginov, S.I. Stepanov
The role of the requirements of the ISO 13314 standard in terms of determining the indicators of absorbed energy and efficiency of absorbed energy is evaluated. The procedure for conducting an experiment and processing its results is described using the example of a cellular structure made of titanium alloy Ti-6Al-4V. The values of indicators for the range of relative porosity of cellular structures of 50–80% have been determined.
Keywords: titanium alloy, cellular structure, compression test, ISO 13314 standard, additive methods.
Influence of additional alloying with hydrogen on the formation of composite structures in alloys of the Ti-Cr system
S.V. Skvortsova, G.T. Zaynetdinova, M.B. Afonina, G.V. Gurtovaya
The paper investigates the regularities of phase and structural transformations in alloys of the Ti – Cr system additionally doped with hydrogen. The influence of hydrogen on the preferred sites for the release of intermetallic compounds and on the line of variable solubility in the Ti – Cr phase diagram was determined. The possibility of controlling the process of structure formation in titanium alloys with eutectoid-forming b-stabilizers by additional alloying with hydrogen and obtaining types of structures that are not characteristic of these alloys with traditional methods of heat treatment is shown.
Keywords: titanium alloys, structure, properties, hydrogen, thermal hydrogen treatment, vacuum annealing, intermetallic compound, composite, aging, thermal stability.
Development of annealing modes for providing the stability of mechanical properties and machinability by cutting VST2K alloy
S.V. Skvortsova, Yu.B. Egorova, L.V. Davidenko, Е.N. Egorov, S.B. Belova
In this paper the modes of heat treatment, which provide an increase in the stability of mechanical properties and characteristics of machinability by cutting the VST2K alloy of different heats, are justified. Heat treatment was carried out at temperatures of 850–1000℃ for 0.5–1.5 h, followed by cooling in air, in water and with an oven. It has been established that in order to increase the stability of the mechanical properties and machinability parameters by cutting hot-rolled semifinished products from the VST2K alloy, it is advisable to use annealing at heating temperatures of 880–920℃, depending on the molybdenum equivalent, followed by cooling with a furnace. Such annealing modes lead to the formation of a globular structure of the same type and provide approximately the same level of properties.
Keywords: titanium alloys, VST2K alloy, chemical composition, heat treatment, structure, mechanical properties, machinability, statistical analysis.
Influence of thermal hydrogen treatment on the forgings structure of titanium alloy VT6 after hot stamping
D.V. Surova, V.I. Polkin, Yu.V. Chernyshova
The paper considers the use of the effect of hydrogen plasticization for hot stamping of titanium alloy VT6, which made it possible to reduce the deformation temperature by 20%. It is shown that by changing the temperature of degassing (vacuum annealing), it is possible to obtain a structure with a given size of structural components, and, accordingly, a given level of properties of a semi-finished product or a product, regardless of the method of obtaining a workpiece. In addition to obtaining high quality products, the economic efficiency of the production of stampings is of no small importance, for which the possibility of using blanks obtained by three different methods was considered: longitudinal rolling, rotary forging, and radial shear rolling. Thermal hydrogen treatment is an effective method for modifying the microstructure and properties of wrought titanium alloys. The method is based on the temporary alloying of titanium alloys with hydrogen. The macro and microstructures of the blanks in the initial state, after hydrogenation, hot deformation, and vacuum annealing, have been investigated.
Keywords: hot stamping, macro and microstructure, thermal hydrogen treatment, VT6 alloy.
Processing technologies
Technological features of manufacturing and processing of fasteners from high-strength titanium alloys by cold deformation
M.B. Afonina, G.V. Gurtovaya, N.V. Ruchina, A.A. Lidzhiev
This work is devoted to the development of heat treatment modes in the manufacture process of fasteners with a diameter of more than 16 mm from titanium alloys VT16 and VT35 by cold plastic deformation. Also in the work, the influence of various types of lubricants on the friction coefficient at the «metal-tool» interface during cold deformation operations was studied.
Keywords: titanium alloys, fasteners, heat treatment, structure, cold deformation, technological plasticity, lubricants, friction coefficient, shear stress.
Multifunctional electron-beam unit ELO-01 for melting the surface of ingots and welding electrodes made of titanium and heat-resistant alloys
A.D. Ryabtsev, P.M. Yavtushenko, A.I. Amelin, S.V. Anokhin, E.A. Amelin, V.P. Khodakovskiy, A.A. Lozhkin, E.I. Lipchanchuk
Proposes an alternative to the traditional (peeling, abrasive processing, etc.) method of surface treatment of titanium ingots, in which it is melted instead of removing defective areas - electron beam melting (ELO). The existing methods of surface melting with an electron beam are shown schematically. The device for electron-beam reflowing ELO-01 is presented and described, technical characteristics of the installation itself, as well as its constituent units - an electron-beam gun, a power source and a vacuum chamber are given. The system of monitoring and control of the complex and the software and hardware complex itself are described. The distinctive features of the installation are shown.
Keywords: titanium, titanium alloy, electron beam reflow, installation, vacuum chamber, consumable electrode.
Application. Quality. Market.
On the role of standards and certification in the production and promotion of products from titanium alloys to the market
Y.N. Kusakina, M.Y. Mastushkin, L.V. Fedorova
The paper discuses some aspects that should be taken into account if someone is going to choose a conformity assessment method in case of titanium products promotion, namely, the issues of technical regulation, the application of international and national standards in the activities of titanium industry enterprises. The possibility of choosing optional certification, taking into account the future market of titanium products and the positive influence of the environmental policy of the enterprise and the policy in the field of sustainable development on the promotion of titanium products to the market, was noted.
Keywords: titanium, titanium alloys, titanium industry, market promotion, conformity assessment, standards.
Thermomechanical behavior of functional composite material based on low density polyethylene reinforced with titanium nickel
D.E. Gusev, M.Yu. Kollerov, E.A. Lukina, R.E. Vinogradov, D.V. Burdin
Deformation and thermal characteristics of shape memory effect of composite material based on low density polyethylene (LDPE) matrix reinforced by NiTi wires have been analyzed at bending tests. Critical strain (ecr0,2) denoted as the total induced strain resulting in 0.2% of unrecovered strain upon unloading and heating and corresponding recovery start and finish temperatures (Аsf and Аfr) are suggested for the characterization of SME in these materials. It has been revealed that ecr0,2 of LDPE- NiTi composite is 6,0%, whereas ecr0,2 of NiTi wires having ecr0,2 = 9,0%. The thermal characteristics of the SME of the composite material and titanium nickelide wire are similar.
Keywords: NiTi alloy, shape memory composite, polymer matrix, low density polyethylene, critical strain, shape recovery temperatures, bending tests.
Estimation of absorbed energy in compression tests of titanium cellular structures of additive manufacturing
Y.N. Loginov, S.I. Stepanov
The role of the requirements of the ISO 13314 standard in terms of determining the indicators of absorbed energy and efficiency of absorbed energy is evaluated. The procedure for conducting an experiment and processing its results is described using the example of a cellular structure made of titanium alloy Ti-6Al-4V. The values of indicators for the range of relative porosity of cellular structures of 50–80% have been determined.
Keywords: titanium alloy, cellular structure, compression test, ISO 13314 standard, additive methods.
Influence of additional alloying with hydrogen on the formation of composite structures in alloys of the Ti-Cr system
S.V. Skvortsova, G.T. Zaynetdinova, M.B. Afonina, G.V. Gurtovaya
The paper investigates the regularities of phase and structural transformations in alloys of the Ti – Cr system additionally doped with hydrogen. The influence of hydrogen on the preferred sites for the release of intermetallic compounds and on the line of variable solubility in the Ti – Cr phase diagram was determined. The possibility of controlling the process of structure formation in titanium alloys with eutectoid-forming b-stabilizers by additional alloying with hydrogen and obtaining types of structures that are not characteristic of these alloys with traditional methods of heat treatment is shown.
Keywords: titanium alloys, structure, properties, hydrogen, thermal hydrogen treatment, vacuum annealing, intermetallic compound, composite, aging, thermal stability.
Development of annealing modes for providing the stability of mechanical properties and machinability by cutting VST2K alloy
S.V. Skvortsova, Yu.B. Egorova, L.V. Davidenko, Е.N. Egorov, S.B. Belova
In this paper the modes of heat treatment, which provide an increase in the stability of mechanical properties and characteristics of machinability by cutting the VST2K alloy of different heats, are justified. Heat treatment was carried out at temperatures of 850–1000℃ for 0.5–1.5 h, followed by cooling in air, in water and with an oven. It has been established that in order to increase the stability of the mechanical properties and machinability parameters by cutting hot-rolled semifinished products from the VST2K alloy, it is advisable to use annealing at heating temperatures of 880–920℃, depending on the molybdenum equivalent, followed by cooling with a furnace. Such annealing modes lead to the formation of a globular structure of the same type and provide approximately the same level of properties.
Keywords: titanium alloys, VST2K alloy, chemical composition, heat treatment, structure, mechanical properties, machinability, statistical analysis.
Influence of thermal hydrogen treatment on the forgings structure of titanium alloy VT6 after hot stamping
D.V. Surova, V.I. Polkin, Yu.V. Chernyshova
The paper considers the use of the effect of hydrogen plasticization for hot stamping of titanium alloy VT6, which made it possible to reduce the deformation temperature by 20%. It is shown that by changing the temperature of degassing (vacuum annealing), it is possible to obtain a structure with a given size of structural components, and, accordingly, a given level of properties of a semi-finished product or a product, regardless of the method of obtaining a workpiece. In addition to obtaining high quality products, the economic efficiency of the production of stampings is of no small importance, for which the possibility of using blanks obtained by three different methods was considered: longitudinal rolling, rotary forging, and radial shear rolling. Thermal hydrogen treatment is an effective method for modifying the microstructure and properties of wrought titanium alloys. The method is based on the temporary alloying of titanium alloys with hydrogen. The macro and microstructures of the blanks in the initial state, after hydrogenation, hot deformation, and vacuum annealing, have been investigated.
Keywords: hot stamping, macro and microstructure, thermal hydrogen treatment, VT6 alloy.
Processing technologies
Technological features of manufacturing and processing of fasteners from high-strength titanium alloys by cold deformation
M.B. Afonina, G.V. Gurtovaya, N.V. Ruchina, A.A. Lidzhiev
This work is devoted to the development of heat treatment modes in the manufacture process of fasteners with a diameter of more than 16 mm from titanium alloys VT16 and VT35 by cold plastic deformation. Also in the work, the influence of various types of lubricants on the friction coefficient at the «metal-tool» interface during cold deformation operations was studied.
Keywords: titanium alloys, fasteners, heat treatment, structure, cold deformation, technological plasticity, lubricants, friction coefficient, shear stress.
Multifunctional electron-beam unit ELO-01 for melting the surface of ingots and welding electrodes made of titanium and heat-resistant alloys
A.D. Ryabtsev, P.M. Yavtushenko, A.I. Amelin, S.V. Anokhin, E.A. Amelin, V.P. Khodakovskiy, A.A. Lozhkin, E.I. Lipchanchuk
Proposes an alternative to the traditional (peeling, abrasive processing, etc.) method of surface treatment of titanium ingots, in which it is melted instead of removing defective areas - electron beam melting (ELO). The existing methods of surface melting with an electron beam are shown schematically. The device for electron-beam reflowing ELO-01 is presented and described, technical characteristics of the installation itself, as well as its constituent units - an electron-beam gun, a power source and a vacuum chamber are given. The system of monitoring and control of the complex and the software and hardware complex itself are described. The distinctive features of the installation are shown.
Keywords: titanium, titanium alloy, electron beam reflow, installation, vacuum chamber, consumable electrode.
Application. Quality. Market.
On the role of standards and certification in the production and promotion of products from titanium alloys to the market
Y.N. Kusakina, M.Y. Mastushkin, L.V. Fedorova
The paper discuses some aspects that should be taken into account if someone is going to choose a conformity assessment method in case of titanium products promotion, namely, the issues of technical regulation, the application of international and national standards in the activities of titanium industry enterprises. The possibility of choosing optional certification, taking into account the future market of titanium products and the positive influence of the environmental policy of the enterprise and the policy in the field of sustainable development on the promotion of titanium products to the market, was noted.
Keywords: titanium, titanium alloys, titanium industry, market promotion, conformity assessment, standards.
