Mark P. Kalashnikov

Study of crack resistance of TiAlN coatings by scratch testing

Scratch tests were performed to study failure mechanisms in TiAlN coatings deposited on substrates from steel 12Cr18Ni9Ti. It is shown that coating failure begins with crack generation at the apices of pile-ups formed along the scratch due to plastic ploughing of the substrate material. With further increase in indentation load the failure process is governed by the competition between tensile stresses behind the indenter arising due to friction force and stresses at the contact area periphery due to coating bending under normal load. Substrate pretreatment by Ti ion beams is shown to simultaneously increase the hardness and crack resistance of TiAlN coatings.

Thermal Cycle Durability of Heat-Shielding Coatings on the Basis of Zr-Y-O/Si-Al-N under Ion Treatment of Copper Substrates

By pulse magnetron deposition method the heat-shielding coatings on the basis of Zr-Y-O/ Si-Al-N layers on copper substrate are formed. Surface layer of copper substrate was treatment by the Zr+ ions. Structure-phase states were investigated by TEM, SEM, X-ray and SIMS. Thermal cycle durability of coatings is defined.

Modifying the structural phase state of fine-grained titanium under conditions of ion irradiation

The results from quantitative investigations into the structural phase state of finely dispersed titanium before and after implantation with aluminum ions are presented. Two types of α-Ti grains differing by phase composition, defect structure, and size are distinguished in the structure: fine grains in the range of 0.1–0.5 μm and coarse grains in the range of 0.5–5 μm. The presence of two types of TiO2 particles in the material, i.e., rounded particles found at dislocations in the bulk of the α-Ti grains and lamellar particles found only inside coarse α-Ti grains, is established. The formation of the Ti3Al phase is observed in the form of lamellar inclusions along the grain boundaries and rounded particles in triple joints. It is found that the particles of the TiAl3 phase are isolated with a smaller volume fraction than the Ti3Al phase; they are localized along the boundaries of coarse grains of the titanium matrix. It is established that the granular state and defect structure of the material change substantially after ion irradiation; i.e., the dislocation density and the fields of internal stresses in fine grains grow considerably, relative to the initial state of titanium.

Influence of Surface Treatment of Copper Substrates by Titanium Ions on Structure and Thermomechanical Properties of Nanocomposite Coatings on the Basis of Si-Al-N

Processing of copper substrates by Ti ions was carried out using «KVANT-03MI» equipment by means of a vacuum-arc ionic source with the titanium cathode. By X-ray and SEM methods it was established that after ionization in the surface layer of substrate the intermetallides of Cu-Ti system form. There is the CuTi3 preferred phase in surface layer of substrate depending on time of processing by Ti ions. The mechanism of formation of observable net structure of surface layer by sputtering of copper atoms by Ti ions the subsequent deposition and their crystallization in the form of microislets of CuTi3 intermetallide on surface of a copper substrate have been suggested.

Intense formation of intermetallic phases during implantation of aluminum ions in titanium

The results from microstructure and phase composition investigations of titanium in different structural states (with average grain sizes of 0.3 μm, 1.5 μm, and 17 μm) are presented following Al ion implantation using the Mevva-V.RU source (irradiating dose, 1018 ion/cm2). The implanted multiphase layers are found to form on the base of α-Ti grains. The size, shape, and localization of the formed phases (TiO2, Ti2O, TiC, Ti3Al, Al3Ti) depend strongly on the grain size of titanium target. It is shown that the nanostructural particles of TiO2 phase are located mainly on dislocations in the body of target grains. A Ti2O surface layer is found to arise in titanium with a grain size of 17 μm. It is established that an ordered Ti3Al phase is located at a depth of more than 200 nm in the implanted layer along the bounaries of the titanium grains.

Elastic stresses and microstructure of TiAlN coatings

By X-ray diffraction and transmission diffraction electron microscopy methods, the phase composition, macro- and microstresses, and microstructure in a Ti1–xAlxN coating and a substrate were investigated. The coatings were deposited by magnetron sputtering of a Ti–Al target in an Ar + N gas reaction mixture on a substrate of austenitic steel 12Kh18N10T preliminarily bombarded with a titanium ion beam. It was found that the increase in the duration of the preliminary ion treatment of the substrate leads to increasing compression macrostresses and refining of a nanocrystalline columnar microstructure in the Ti1–xAlxN coating.

Structural and phase transformations in 0.3C-1Cr-1Mn-1Si-Fe steel after electrolytic plasma treatment

The paper presents the transmission electron microscopy (TEM) investigations on thin foils concerning phase transitions occurred in the type 0.3C-1Cr-1Mn-1Si-Fe alloyed steel after the electrolyte plasma treatment, i.e. carbonitriding at 850°C during 5 min. TEM investigations involve two points, namely: on the specimen surface and at 50 µm distance from the surface, i.e. in transition layer. It is shown that carbonitriding results in the formation of structures the properties of which are changed at a distance from it’s the specimen surface. Thus, the modified morphology of the steel matrix is represented mostly by high-temperature lamellar martensite on α-phase surface, while the intermediate layer is represented by massive martensite. After carbonitriding, the particles of the alloyed cementite and M2C0.61N0.39, M4(C,N), M7(C,N)3, M23(C,N)6 carbonitrides are observed in all layers inside α-phase crystals and at their boundaries. The concentration of carbon and nitrogen on the surface is considerably hig...

Internal stresses and structure of multilayer coatings on the basis of Zr-Y-O / Si-Al-N

X-ray and TEM research of the structure of multilayered coatings consisting of the alternating layers Si-Al-N and Zr-Y-O of equal thickness are carried out. It is shown that the boundaries between different layers are sharp enough, and the chemical composition in each layer is homogeneous. The phase composition of the layers on the basis of Zr-Y-O contains basically nanocrystalline ZrO2 and the layers on the basis of Si-Al-N contain Si3N4 amorphous phase. The internal field of stresses is determined by X-ray and TEM analyses. It is established that the crystal lattice curvaturetorsion and the internal elastic stresses depend on the grain cross-section size of the Zr-Y-O layer.

Magnetron deposition of metal-ceramic protective coatings on glasses of windows of space vehicles

Transparent refractory metal-ceramic nanocomposite coatings with a high coefficient of elastic recovery and microhardness on the basis of Ni/Si-Al-N are formed on a glass substrate by the pulse magnetron deposition method. The structure-phase states were investigated by TEM, SEM. It was established that the first layer consists of Ni nanograins with a fcc crystalline lattice, the second layer is two-phase: 5-10 nm nanocrystallites of the AlN phase with the hcp crystalline lattice in amorphous matrix of the Si3N4 phase.

Influence of intense bombardment of Cu+ ions on microhardness and structure of VT-23 titanium alloy

The structural-phase state of the ion-modified surface layer of the VT-23 titanium samples was investigated by TEM and SEM. The results of the surface modification of the VT-23 titanium alloy by the intense flux of copper ions with energy of 2 keV and the ion current density of 3.5 mA/cm2 were studied. The dependence of the microhardness and the penetration depth of ions as a function of duration of ion treatment was determined. The microhardness was investigated by the nanoindentation method.