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Publications (203)
The influence of an ultrafine-grained tungsten structure with an average grain size of 300 nm on the formation of blisters on the surface under high-fluence irradiation by 30-keV He + ions has been studied. Fine-grained tungsten has been used for comparative studies. The microstructure and surface morphology of the samples have been investigated.
The effect of deformation nanostructuring of copper, nickel, and titanium on ion-induced morphology and sputtering under 30 keV argon ions high-fluence irradiation along the normal to the surface has been studied. Sputtering of a layer commensurate with the size of metal grains leads to a uniform cone-shaped relief, the stationary erosion of which...
High-pressure torsion was used to obtain bulk nanostructured Ti and nanospike surface was further obtained
after irradiation with 30 keV Ar+ ions. The homogeneous nanospikes with the height of 200 nm and spacing
between them of 100 nm were obtained. No alive E. coli bacteria were found on the homogeneous nanospike
surface.
The effect the deformation nanostructuring of copper, nickel, and titanium on ion-induced morphology and sputtering upon high-fluence irradiation with 30-keV argon ions normal to the surface has been studied. The sputtering of a layer commensurate with the size of metal grains induces a homogeneous cone-shaped relief whose stationary erosion procee...
The effect of deformation nanostructuring on the ion-beam erosion of copper at a high fluence of irradiation with 30 keV argon ions is experimentally studied. To form an ultrafine-grained structure with a grain size of ~0.4 μm in copper samples with an initial grain size of about 2 μm, deformation nanostructuring by high-pressure torsion is used. I...
The effect of deformation nanostructuring on ion-beam erosion of copper at high fluences of irradiation with 30 keV argon ions was experimentally studied. Deformation nanostructuring by high-pressure torsion was used to form an ultrafine grained structure with a grain size of ~0.4 µm in copper samples with an initial grain size about 2 µm. It was f...
The results of the study of the effect of deformation nanostructuring on the formation of a cone-shaped relief on the surface of ultrafine-grained tungsten with an average grain size of 300 nm under high-fluence irradiation with argon ions with an energy of 30 keV are presented. The thermal stability of the resulting cone-shaped relief on the surfa...
In order to find the ways of giving antibacterial properties to implants, a homogeneous nanospike morphology on titanium surface was formed by deformation nanostructuring followed by bombardment by high-fluence Ar + ions. Taking account of the fact that antibacterial properties were studied on an example of E. coli bacteria, nanospikes having a hei...
The studying the effect of multiaxial isothermal forging on the microstructure and martensitic transformation in the Ni58Mn18Ga24 alloy is presented. Forging was carried out in two stages: stage 1 − forging at 700°C (4 passes, true degree of deformation e ≈ 1.64), stage 2 − forging at 500°C (1 pass, e ≈ 0.24). Forging led to the transformation of t...
The results of an experimental study of the effect of high-fluence ion irradiation on the thermal stability of the microstructure and surface relief of submicrocrystalline nickel are presented and discussed. The submicron structure of nickel is obtained during severe plastic deformation by torsion under a high pressure of 6 GPa. Irradiation with 30...
The results of an experimental study of the effect of high-fluence ion irradiation on the thermal stability of the microstructure and surface relief of submicrocrystalline nickel are presented and discussed. The submicron structure of nickel was obtained during the severe plastic deformation by torsion under high pressure of 6 GPa. Irradiation with...
Mechanical alloying of dissimilar metals employing the severe plastic deformation techniques established itself to be a perspective method of obtaining in situ metal matrix composites with advanced properties. Recent investigations in this field discovered that besides severe mixing of elements, intensive formation of non-equilibrium intermetallic...
In the present work the processing using high-pressure torsion (HPT) on Bridgman anvils with grooves of Al-Nb composite and tensile properties of this composite were investigated. Constrained HPT processing was applied to a set of three disks with the alternation of layers, i.e., Al-Nb-Al. at room temperature under a pressure of 5 GPa for 30 revolu...
We present the results of studying the erosion and ion-induced electron emission of nickel samples with nano-, micro-, and coarse-crystalline structures under high-fluence irradiation with 30-keV argon ions. The nanostructure is formed using high-pressure torsion deformation. The irradiation of nanostructured nickel led to the formation of cones on...
The Heusler alloys demonstrate magnetically induced strain and magnetocaloric properties, but the mechanical properties are poor. Therefore, in this work, the influence of thermomechanical treatment on the properties of Ni-Mn-Ga-Si Heusler alloys is considered. The effect of multi-axial isothermal forging on functional properties of the Ni2.30Mn0.7...
Multilayered bulk Al–Cu–Al metal-matrix composite was fabricated by means of high-pressure torsion and subsequent annealing. The resulting composite had a heterogeneous structure consisting of ductile aluminum matrix and hard intermetallic inclusions with a gradient decrease in grain size and layer thickness when moving from the center to the perip...
A hybrid composite material fabricated from the Al-Nb system using high-pressure torsion (HPT) up to 30 turns has been studied in the present work. To fabricate the composite, deformation of a three-layer Al-Nb-Al package was carried out at room temperature on Bridgman anvils with grooves under a pressure of 5 GPa at N=10, 25 and 30 revolutions, at...
Al and Nb billets with a coarse grain structure in the form of thin discs were stacked in the order of Al-Nb-Al and then deformed by shear under pressure. After the deformation the samples were annealed at 500°C for 30 min. The formation of an intermetallic compound AUNb was revealed by using X-ray diffraction and energy-dispersive spectroscopy. Af...
Abstract. Among different approaches for obtaining composite structures, one can distinguish the approach of severe plastic deformation that allows obtaining bulk structures from strongly
dissimilar metals. The application of large strains is usually associated with grain refinement and, in some cases, with the formation of intermetallic phases, bo...
Nanostructured samples of Fe - 36% Ni (Invar alloy) and Fe - 50% Ni alloys with a fragment size of about 100 nm were obtained by high pressure torsion using Bridgman anvils. The formation of the nanostructure leads to a decrease in the coefficient of thermal expansion of the Fe - 36% Ni and Fe - 50% Ni alloys by 2.2 and 1.2 times, respectively. Ann...
The main point of successful manufacture of metallic composites by direct bonding of dissimilar materials is achieving a homogeneous interface bonding. Two different types of deformation techniques for fabrication of metal composites were investigated. The first one was developed on the basis of high pressure torsion associated with a high energy i...
A hybrid composite material fabricated from the Al – Nb system using severe plastic deformation by high-pressure torsion (HPT) up to 30 turns has been studied in the present work. To fabricate the composite, deformation of a three-layer Al – Nb – Al package was carried out at room temperature on Bridgman anvils with grooves under a pressure of 5 GP...
Using molecular dynamics simulation, the dehydrogenation process of a crumpled graphene flake during annealing at 77, 100, 150, 200, 250, and 300 K for 200 ps is considered. It is found, that annealing at T = 77 K during the first 50 ps does not affect the gravimetric density. Further, exposure at this temperature results in a sharp decrease in the...
The main approach of mechanical consolidation of dissimilar metals consists in solid state joining of thin discs or powders by means of pressure‐assisted shear deformation. Prior to this research, most strongly dissimilar systems, such as Al–W and Al–Ti, were only bonded by means of mechanical alloying and subsequent powder compaction. Herein, pion...
Multilayered Al-Cu composites were fabricated successfully by constrained high-pressure torsion (HPT) in a Bridgeman anvil type unit under an applied pressure of 6.0 GPa after ten turns. Due to the good strain compatibility of Al and Cu, achieved during HPT, separate discs bonded without pores and cracks. Microstructural characterization of the pro...
Field electron emission from a copper based composite reinforced with carbon nanotubes (Cu-4 wt.% CNT) was studied. The composite samples were processed by mixing copper powders and carbon nanotubes (CNTs) in a ball mill followed by hot isostatic pressing. To obtain a more even distribution of CNTs, the samples were subjected to high pressure torsi...
Selective laser sintering was applied for stainless steel samples additive manufacturing. It was found that in the as fabricated state, the samples consist of martensite and residual austenite, contained significant dislocation density and residual stresses. Additively manufactured samples had an ultrafine-grained structure with predominantly high...
Results are presented from studying the structure and mechanical properties of an Al–Cu–Al metal-matrix composite obtained via shear under pressure on Bridgman anvils with grooves. The tensile strength is 485 MPa, considerably higher than that of either pure aluminum or copper. The main mechanism of failure is a viscous fracture along the Al matrix...
Constrained high pressure torsion and subsequent annealing was used to fabricate Al-Cu-Al metal-matrix multilayered composite. The composite has a heterogeneous structure consisting of a plastic aluminum matrix and hard intermetallic inclusions with a gradient decrease of layer thickness from the center to periphery of the sample. Intermetallic gro...
Graphane is a fully hydrogenated graphene which is practically interesting for application in electronics, hydrogen storage and transportation, in nanoscale devices. As it was previously shown, the energy of a discrete breather (nonlinear localized mode) in graphane close to the value of the energy barrier at which the dehydrogenation of graphene o...
The paper presents first results of obtaining metal-matrix composites based on severe plastic deformation by shear under pressure of layered Al and Cu components. Three-layer composites with different alternation of layers, i.e. Al-Cu-Al and Cu-Al-Cu, were processed by constrained high pressure torsion to produce monolithic disk-shaped samples with...
his book combines the perspectives of materials science of Superplasticity, on the one hand, and those of design and mechanics, on the other, in order to provide a holistic view of materials, design, mechanics and performance which will lead to useful solutions of societal benefits, in addition to providing great intellectual challenges. After cons...
A short review on the results of research and development on superplasticity of alloys and related processes such as grain refinement, solid state bonding carried out at the Institute for Metals Superplasticity of the Russian Academy of Sciences (IMSP RAS) is given. One of the most important contributions of IMSP RAS to the fundamentals of superpla...
The influence of deformation nanostructuring and subsequent annealing on the temperature dependence of the thermal expansion coefficient of the Fe-36% Ni Invar alloy is studied. The nanostructured state was obtained by severe plastic deformation via high pressure torsion in Bridgman anvils. An "anomalous" contraction of the nanostructured Fe-36% Ni...
Selective laser sintering was used for additive manufacturing of stainless steel parts. The microstructure of the initial powder and the as-processed part was investigated. It was found that high temperature gradients involved in selective laser sintering evolve non-equilibrium microstructures in the as fabricated state, e.g. retained austenite in...
The effect of nanostructuring on the ion sputtering rate of metals and the glow discharge current is studied. Nanostructured samples were processed by severe plastic deformation using high pressure torsion. For comparative measurements, coarse-grained samples were obtained by annealing of nanostructured samples. The sputtering rates of nanostructur...
This paper presents the data from the study on the effect of annealing of Al-Cu metal-matrix composites, produced by severe plastic deformation via shear under pressure. Three-layer compositions with different alternations of layers (Al-Cu-Al and Cu-Al-Cu) were subjected to deformation by high-pressure torsion, and then annealed at a temperature of...
The manuscript considers the effect of diffusion bonding pressure, as well as holding at different temperatures, on the strength of the joints between titanium alloy and stainless steel, formed by diffusion bonding through ultrafine-grained interlayers of Ni and the Ni-2%Cr alloy. In samples with an interlayer of nickel after holding at 25 °C, the...
The work presents the comparative analysis of the microstructure and character of martensitic transformation in Heusler Ni-Mn-Ga alloys subjected to plastic deformation by forging and complex treatment by forging with subsequent extrusion. It is shown that the treatment by forging leads to the formation of a bimodal structure with large grains of s...
The method utilizing high-pressure torsion (HPT) processing followed by annealing to fabricate Cu-Al in situ composite with enhanced mechanical properties is presented. The initial sample consists of three metal discs Cu/Al/Cu was processed by HPT (5 GPa, 5 turns). The analyses of the microstructure after HPT carried out by transmission electron mi...
The formation of a sharp crystallographic texture in a Ni–Mn–Ga Heusler alloy by the multiple isothermal forging has been studied. An analysis of the thermal expansion near the martensitic transformation temperatures in the as-cast and forged states of the alloy shows that the thermomechanical treatment leads to an increase in the anisotropy of the...
The application of the method of molecular dynamics based on the use of pair interatomic potentials has been discussed to study various deformation processes during structural and phase (martensitic) transformations in metallic single and polycrystals. It has been shown that the method of molecular dynamics in a two-dimensional model makes it possi...
The mechanical properties and the fracture of the joints between a PT3V titanium alloy and 12Cr18Ni10T stainless steel formed by diffusion welding through ultrafine-grained layers of nickel and a Cr2Ni98 alloy are studied. The highest strength of the joint (about 390 MPa) is achieved upon welding at T = 700°C, 20 min irrespective of the interlayer...
Changes of properties and the second phase particles’ distribution in diluted CuCrZr alloy in the course of equal channel angular pressing (ECAP) and post-deformation annealing are investigated. To decrease the concentration of alloying elements dissolved in the copper matrix, samples of the alloy were thermally aged prior to the ECAP. Temperature...
Environmental superplasticity is demonstrated in polycrystalline materials that experience an anisotropic dimensional change in specific environment conditions [1].
Like conventional alloys, usually brittle intermetallic alloys (TiAl, Ti3Al, Ni3Al etc.) in a fine-grained condition under a certain temperature-strain rate intervals display superplastic behavior [994–1003]. Phenomenological features like high elongation, low flow stress, high strain-rate sensitivity index and deformation mechanisms were found to...
Structural superplasticity in relatively higher melting temperature materials such as Titanium alloys, Steels and Ni based alloys is discussed in this chapter.
Scientific investigations on Superplasticity started with the works of Bengough [494], the scientists at the old Kaiser Wilhelm Institute in Berlin and Pearson [28], all from the early years of the twentieth century.
Theories of superplasticity are reviewed in this chapter in the following order. (a) Theories of structural superplasticity, (b) Theories of environmental/transformation superplasticity. The theories proposed from the former Soviet Union during 1945–1962 are often referred to as the early theories and those propounded since the mid-1960s are known...
The “superplasticity-like” behavior of geological materials, i.e. minerals, combinations of minerals, spinels, rocks etc., polycrystalline ice, amorphous materials (bulk metallic glasses) and some exotic materials like hydroxyapatite and CNT is discussed in this chapter.
A majority of superplastic alloys require suitable thermo-mechanical processing to develop a microstructure conducive to superplastic deformation [11,13,14]. Several processing routes, including severe plastic deformation techniques, result in ultrafine grained (UFG) and nano-structured (NS) materials. Friction-stir processing (FSP) is one of the w...
Techniques derived from thermoplastics forming processes, and
The results of investigation of the microstructure of two polycrystalline Ni-Mn-Ga alloys subjected to thermo-mechanical treatment by multiple isothermal forging and extrusion are presented. Alloy forging at a temperature of 680°C and 700°C leads to the formation of a bimodal structure which has large grains of several hundred micrometers surrounde...
The temperatures ductility of the polycrystalline Ni2.19Fe0.04Mn0.77Ga alloy was investigated. The analysis of the temperature dependence of the specific magnetization shows that temperatures of the martensitic and magnetic phase transformations have the following values: MF=325 K, AS=343 K, TC=365 K. The differential scanning calorimetry shows tha...
The plastic behavior during deformation by upsetting and its effect on the microstructure in the polycrystalline Ni2.19Fe0.04Mn0.77Ga alloy are studied. The temperatures of martensitic and magnetic phase transformations were determined by the method for analyzing the temperature dependence of the specific magnetization as MF = 320 K, AS = 360 K, an...
In the paper, microstructure design by means of hot working and heat treatment as well as some mechanical properties have been considered for intermetallic alloys based on γ(TiAl) and O(Ti2AlNb) phase. It has been shown that the current scientific and technical knowledge creates the prerequisites for development of both cast and wrought processing...
The paper presents the results of plastic deformation by the multiple isothermal forging on microstructure and martensitic transformation in polycrystalline Ni54.1Mn19.6Ga24.6Si1.7 alloy. The method of plastic deformation was applied to Heusler alloys for the first time. By recording the temperature dependence of thermal expansion in the field of t...
The paper presents the results of studies on the effect of deformation nanostructuring of cathodes from aluminum alloy Al-6%Mg on the glow gas-discharge current in a discharge device. Microstructure and work function of nanostructured alloy are studied. It is shown that a decrease of the work function as a result of alloy nanostructuring leads to a...
The present work is devoted to the development of the production of three-layered hollows structures made of VT6 titanium alloy by means of superplastic forming (SPF) and pressure welding. Finite-element modeling can be successfully applied to optimize the forming process, if the adequate constitutive relations would be defined and the friction at...
Babbitt alloys are traditionally used as a material for sliding bearings of large-sized units. The structure of babbit Sn11Sb5,5Cu consists of three phases: α-phase, which is a solid solution of antimony and copper in the tin, β-phase is a SnSb crystal with hexagonal and rhombohedral lattice and small η-phase (Cu6Sn5 compound). Refinement of presen...
The effect of heat and thermomechanical treatments conditions on the microstructure and main mechanical characteristics (obtained by tensile, high-temperature long-term strength, fracture toughness, and high-cycle fatigue tests) of the Ti–45Al–5Nb–1Mo–0.2B (аt %) alloy was studied. Before the treatments, the sequence of phase transformations in the...
Investigations of technological properties of new titanium alloy sheet VST2k have been conducted. It is found that the titanium alloy has a good solid state weldability and formability under conditions of superplasticity at temperatures 750-900C. By the method of SPF/DB sheet of VST2k alloy in a low-temperature superplasticity at a temperature of...
The structure and properties of a polycrystalline Ni–Mn–In Heusler alloy have been studied after a plastic deformation by upsetting. An analysis of points of a martensitic and magnetic phase transformations shows that the martensite transformation takes place at temperatures lower than the Curie point. At high temperatures in the range 930–1110 K t...
Equilibrium structures obtained by linking with valence bonds the carbon carcasses of two fullerene-like molecules have been studied by molecular dynamics simulation. In free fullerene, carbon atoms form sp
2 hybridized bonds, but at places of links between fullerenes, sp
3 hybridized bonds are formed, which determines the changes in the properties...
The results of development of new resource-saving technologies of local shape-forming under superplastic deformation conditions (SP) by means of roll-forming and rotary swaging are presented. These technologies are efficient for fabrication of discs, shells, rings up to 800 mm in diameter, as well as hollow shafts made of heat-resistant nickel-, ti...
Application of the conventional superplasticity (SP) allows producing the unique hollow structures. One remarkable example is the hollow titanium blade of the air engine fan produced by Rolls-Royce. However, high temperature titanium alloys processing (~ 927 °С) limits wide industrial application of the conventional SP. The solution of the mentione...
Results: are presented of a study of the temperature dependence of the magnetization σ(Т) of the polycrystalline Ni52Mn24Ga24 alloy in various structural states: in the initial coarse-grained state, after severe plastic deformation by high pressure torsion, and after stepped annealing of the deformed specimen at temperatures from 200 to 700°С for 3...
Microstructure, nanohardness, and special features of fracture of three-phase titanium alloy and stainless steel joint through a nanostructural nickel foil are investigated. Uniformly distributed microcracks are observed in Ti2Ni and TiN3 layers joined at temperatures above T = 700°C, whereas no microcracks are observed in the TiNi layer. This sugg...
Composites with a copper matrix, reinforced by carbon nanotubes, have been produced by the multistage method including functionalization of carbon nanotubes, their dissolution, mixing with a copper powder, preliminary warm isostatic compaction, and severe plastic deformation by torsion. The microstructure and microhardness of composites containing...
Studies of the relief formed on the surface of nanostructured nickel with nonequilibrium grain boundaries formed upon ion-beam sputtering are presented. It has been shown that the relief on the nano-structured nickel surface differs substantially from the relief formed on the surface of the coarse-grained nickel with equilibrium grain boundaries. I...
Composites with a copper matrix, reinforced by carbon nanotubes, have been produced by the multistage method including functionalization of carbon nanotubes, their dissolution, mixing with a copper powder, preliminary warm isostatic compaction, and severe plastic deformation by torsion. The microstructure and microhardness of composites containing...
Research of microstructure, X-ray diffraction and microhardness metall-matrix composites reinforced with carbon nanotubes (CNT) obtained by severe plastic deformation were carried out. As starting materials for the preparation of composites multi-walled CNT and powders of copper and aluminium were used. Composites in the form of discs with a diamet...
A study of the relationship of the crystallographic texture, the preferential orientation of martensite twins and the geometry changes during the martensite transformation of polycrystalline NiMnGa alloy is shown. Two states of alloy are investigated: as-cast state and the state after annealing at 923 K for 5 hours. It is shown that in the initial...
23 декабря 2014 г. Представлены результаты исследования рельефа, формирующегося на по-верхности наноструктурного никеля с неравновесными границами зерен в ре-зультате ионно-лучевого распыления. Показано, что полученный на поверхно-сти наноструктурного никеля рельеф существенно отличается от рельефа, об-разующегося на поверхности крупнокристаллическ...
Uniformity of deformation in bonding zone during pressure welding of titanium alloy to stainless steel with nickel interlayer was studied. It was shown that in the case of flat surfaces the stagnant zones in the center of the samples are formed and formation of bonds takes place non-uniformly: edges of the samples are seized, while in the center th...
The results of a study of the martensitic transformation in the polycrystalline Ni52Mn24Ga24 alloy in different structural states are presented in the article. In the initial state in the alloy magnetic and martensitic phase transformation is observed with the following characteristic points: MS=25°C; MF=15°C; AS=35°C; AF=45°C; TC=127°C. The alloy...
Based on Backofen constitutive equation of 5A06 aluminum alloy at high temperature tensile test, get 5A06 aluminum alloy best superplastic constitutive equation parameters: when T= 400°C,m=0.39, K=270.34.5A06-O aluminum alloy cup gas bulging forming process is simulated with using the method of MARC finite element analysis .By designing a variety o...
Crumpled sheet materials appear at different scales ranging from crumpled graphene composed of nanoscopic structural units to crumpled paper balls and crumpled foils. There exist a number of studies analyzing fractal geometry of crumpled materials, while their mechanical properties are not well addressed in the literature. In the present study the...
The effect of ultrasonic treatment (UST) on the microstructure and mechanical properties of bulk nanostructured nickel processed by equal-channel angular pressing (ECAP) is studied in the range of stress amplitudes between 0 and 100 MPa. It is shown that UST results in a considerable simultaneous increase of the ultimate strength and ductility of t...
Summarizing the results of the studies performed at IMSP RAS, the principles of processing of a uniform ultrafine-grained (UFG) structure in large-section billets by means of the technique of multiple isothermal forging are formulated. These principles imply a uniform introduction of plastic strain energy into large-section billets, minimization of...
Scientific bases of a technology for superplastic roll forming of axially symmetric parts of gas turbine engines that are made of heat-resistant alloys are described. It is shown that a formed microcrystal structure allows their deformation under conditions of superplasticity, thereby providing changes in physical and mechanical and processing prop...
The uniaxial tension of NiAl and FeAl intermetallic alloy nanofilms at different temperatures has been investigated by the molecular dynamics method. It was previously shown that nanofilms at 0 K are elastically deformed by almost 40% and that, under strain-controlled tension, there is a region in the stress—strain curves, where an increase in the...
