Section of Experimental methods in materials research

Experimetnal spectrum of crystal curvature enables to discriminate between bainite and marnetsite and quantify them. To this end a main phase is fitted first to relevant spectrum tail.

Even in simple experiments on uniaxial tension of filled elastomeric materials, an inhomogeneous strain field is observed in a standard dumbbell-shaped sample, not to mention experiments with complex loading history. The way out of this situation is to use samples of a different shape, for example, ring-shaped, rather than dumbbell-shaped samples.

Schematic illustration of impact specimen cutting from multilayer laminate in the crack divider orientation

The study of the process of phase formation of multicomponent pyrochlore (Bi2-хCr1/6Mn1/6Fe1/6Co1/6Ni1/6Cu1/6Ta2O9+Δ) in the course of solid-phase synthesis showed that the precursor of the pyrochlore phase is bismuth orthotantalate. Of all the precursors, cobalt and nickel oxides are the last to enter the chemical reaction (at 850-900 С). Intermediate phases in the course of synthesis are complex oxides Bi16CrO27, Bi25FeO40, BiTaO4, Bi3TaO7, СoTa2O6.

At room temperature the permittivity and dielectric loss tangent of Bi2-1/3Cr1/6Mn1/6Fe1/6Co1/6Ni1/6Cu1/6Ta2O9+Δ are ~46 and ~0.004 at 1 MHz, respectively.

Changes in the microstructure of quenched pure iron after the tempering procedure for 1 hour at a temperature of 160 - 220 °C.

The method of confocal laser scanning microscopy (CLSM) has demonstrated significantly higher sensitivity for assessing of corrosion damages than standard gravimetric method. Moreover, the CLSM method has enabled to obtain the quantitative assessment of average corrosion rate, as well as localized one.

the studies carried out show that by varying the nature of the solvent, the concentration and nature of the polymers in the initial solutions, it is possible to control the structure formation in mixed polymer solutions, and, therefore, the properties of the resulting composites.

Thermoelectric materials are designed according to thermoelectric characteristics, which require good agreement with the Zeebeck coefficient, electronic conductivity, and thermal conductivity. This paper is presented the comparative data of thermal properties in five compounds of nanocrystalline copper sulfides KxCu1.85S (0<x <0.05) at the temperature zone from 300 K to 700 K. X-ray phase analysis shows a mixture different phases of copper sulfides such as Сu1.85S cubic phase, Cu2S cubic phase, Cu17S9 (Cu1.89S) rhombohedral phase, Cu2S tetragonal phase in all investigated compounds at room temperature. The sizes of crystallites in the alloys estimated from half-width of X-ray lines are in range from 24 to 90 nm. The thermal conductivity of alloys decreases to 0.2 ÷ 0.6 W K-1m-1 in temperature range of 350 – 700 K due to increasing of the amount of potassium (for x = 0.04, 0.05). This guides the maximum thermoelectric characteristics of the material. The obtained results are important for semiconductor materials used in the field of thermoelectric devices.

The chemical composition and adjustment of pH value of the simulated body fluid exert a significant effect on the susceptibility of the alloy ZK60 to stress corrosion cracking

It is shown that radial-shear rolling makes it possible to form a gradient structure in the 58Ni-Cr-Mo-B-Al-Cu superalloy billet. In which the recrystallized grains size of the γ-phase in the radial direction from coarse-grained (34.1 ± 4.7 μm) in the center to ultrafine-grained (2.4 ± 1.7 μm ) in the surface layers of the billet cross-section. This leads to a gradient change in microhardness. The microhardness value is 3.3 GPa in the billet center, and the microhardness increases to 5.4 GPa in the peripheral near-surface zone.

Microstructure of cemented carbide. Ellipse marks the example of the analyzed “island” Co grains. CW and PW mark the example of WC/WC GBs completely and partially wetted by a Co binder. IA and OA are incoming and outcoming angles in the cobalt binder.

From the interpretation of the obtained XPS- and NEXAFS 2p-spectra of atoms in Co-doped CaCu3Ti4O12 and the corresponding oxides it was concluded that in ceramics the copper and calcium atoms have a charge state of +2, the titanium atoms have a slightly lower charge than +4, and cobalt atoms have mainly a charge of +2 with some fraction of Co(III) ions in the high spin state.

Confocal laser scanning microscopy technique allows high accuracy reconstruction of the corrosion damage topology, providing access to the assessment of the metal's volume loss and the corrosion rate

Prediction exactly of the failure zone in Lead rupture within the same non-homogeneous zone previously detected exactly using Scanning Contact Potentiometry technique,which was done in the elastic mode before conducting the tensile test.

During fracture of high-pressure pipelines, the longitudinal crack can stop in one of two ways, which are discussed in the article.

Assessment of the performance of carbon Nano tube reinforcement in Nano composite coatings.

The use of such lubricant SM6 (L6) in the manufacture of rope increases the durability of the rope at positive temperatures in relation to the unsmained rope by 2.2 times, and at a temperature of 60 degrees C the durability of the rope, soaked in this lubricant, lower than the unsubstuded (dry) rope.

The sample have wide impedance-spectra, demonstrating three relaxation processes separated by frequency. An equivalent scheme has been proposed and its parameters have been calculated, satisfactorily describing the electrical characteristics of the preparation.

The relation of the coefficient n in the equation hmax=1/nπ ((K1C (KC ))/σ0.2 )2 (where hmax is the maximum depth of the plastic zone under the fracture surface) with the criterion of the local stress state hmax/t for CG and UFG materials with BCC, FCC and HCP lattice when testing samples for static crack resistance

Diffraction reflections KCl (200) at room temperature (T0=297.1 K) and in premelting stage (T2=1018.2 K)

Cr Doped tungsten oxide nano structures and non linear I-V, C-V, Admittance and Impedance Measurements

The dependence of the elastic modulus on the composition of the composite

Dependences of the eddy current device readings α at different frequencies on the number of loading cycles N, measured within contact spots after contact fatigue tests of the cobalt-nickel-chromium PG-10K-01 coating

Shows the effect of friction force on energy-power parameters and deformation before fracture under lug billet in strips of aluminum alloy Al-31. The effect of fragmentation on the degree of deformation strain before breaking down and the voltage drawn under different conditions of friction between the workpiece and the cutting tool.

The structure of CaCu3Ti4O12 equivalent circuit reveals three processes possible within the material – reach-through conductivity and two overlapping polarization processes – electronic and dipole relaxation ones. Temperature dependencies of specific conductivity in the Arrhenius scale for CaCu3Ti4O12 samples of different thicknesses are linear and characterized by activation energy of 1.05 eV. Temperature dependencies of electric parameters of samples are at their minimums at T = 350 C, which can be explained by the changed polarization mechanism.

In the alloy containing the LPSO phase, using the acoustic emission method, it was possible to identify and trace the kinetics of the development of three simultaneously occurring accommodative deformation mechanisms: basic dislocation slip, nucleation and growth of discharge bands.

Capabilities of Incremental Forming increased with the help of controlled heating.

The analysis of the NEXAFS Co2p-spectra of cobalt-containing solid solutions and cobalt oxides revealed that the studied Co atoms were mainly in the +2 and +3 oxidation state, which correlates well with the magnetochemical study data.

The study of the magnetic susceptibility of iron-doped solid solutions with layered perovskite-like structure has been established the influence of atoms of the second coordination sphere on the degree of aggregation and the nature of exchange interactions in the exchange-bound clusters containing Fe(III) atoms.

Shows the effect of friction force on energy-power parameters and deformation before fracture under lug billet in strips of aluminum alloy Al-31. The effect of fragmentation on the degree of deformation strain before breaking down and the voltage drawn under different conditions of friction between the workpiece and the cutting tool.

At present work established that, depending on the direction of scratching, the hardness and the AE power exhibit opposite trends, both following the anisotropic properties of a cubic crystal lattice. It is shown that the direction of scratching affects not only the energy of the AE signal, but also its spectral characteristics.

The dependence of complex viscosity of a melt of mix PP with HDPE-20 (1) and LDPE-276 (2) defined with a frequency of oscillation of 0,1 Hertz on a ratio of polymers in mix.

investigation of the destruction of steel AISI 316 by electron microscopy and SCP methods. To confirm the results obtained by the methods of structural analysis, methods of measuring microhardness and roughness were also used.

The electrical properties of the CaCu3Ti4O12–СuO composite were studied by the method of impedance spectroscopy

In the three-layer composite PZT / FeRh / PZT, the possibility of control the temperature of the magnetic transition and width of the hysteresis by electric field was demonstrated.

The research of dispersed precipitates in high-strength medium-carbon steel after tempering in the temperature range up to 600 °C was carried out. Amount of retained austenite decreases and cementite is forming instead of austenite by growth of the tempering temperature.

The function of the force parameters (axial force and torque) recorded in the experiment and the preset kinematic parameters (the rate of tension and the torsional velocity), the strain rate sensitivity coefficient and the approach angle between the stress vectors and the strain rate on the specimen surface under complex loading.

The results of an investigation of the EPR and the magnetic susceptibility of BiNb1-xFexO4-δ orthorhombic modification

A microphotograph of a cross-section of SMFM-Pb with a porous bronze layer having a "columnar" structure: 1 - steel base, 2 - spike of the bronze layer, 3 – PTFE-composition.

On the original laboratory bench, which allows to simulate the technological cooling rates of hot-rolled sheets in the process of controlled thermomechanical processing, the thermal effect of bainitic transformation in low-carbon low-alloy tube steel 06G2MB type is determined.

Due to nonparametric criteria, the presence of one or several types of structural elements of the relief on the faces of samples was identified and their scale hierarchy is shown.

Metallographic methods were used to study the viscous character of the deformation in the regions of strong localized flow, including Roaldite (Fe, Ni) 4N plates in the alpha (Fi, Ni) meteorite of the Sikhote-Alin meteorite.

Field neon image atomic clean and atomic smooth the surface of platinum single crystal before irradiation, with the corresponding stereographic projection. By irradiation of the single crystal Pt beams of charged Ar+ ions are able to obtain nano-structured state of the material under certain modes in the near-surface volume of the nano meter range.

Shock-wave loading of reactive materials by throwing a flyer

Many questions remain open in the understanding the role of microstructural factors in the acoustic emission (AE) phenomenon occurring in deforming materials. A comparative analysis of AE time parameters in tensile testing of pure aluminum, copper, silver and nickel specimens having very different values of stacking fault energy (SFE) was undertaken in the present work to clarify the SFE effect on the AE signal. Continuous digital wideband recording was used for AE waveform registration, which offers the possibility to avoid the threshold discriminators and to analyze a continuous AE signal generated during plastic deformation mediated by dislocation mechanisms. The power of the AE signal were selected as the descriptive parameters. Following the evolution of dislocation structures, the AE energy parameters were demonstrated to have a similar behavior in all investigated materials, i.e. the AE level increases sharply at the onset of plastic flow and then decays gradually during the uniform strain hardening stage. However, the absolute values of the AE amplitude and energy differ significantly depending on SFE. It was shown unambiguously that in contrast to expectations, the AE energy parameters reduce as the SFE value increases. This effect is discussed qualitatively in terms of the features of dislocation behavior, which are governed by the SFE value.

The microstructure and local mechanical properties of zones of 12Cr18Ni10Ti steel and a titanium alloy VT1-0 with an intermediate copper insert joint were carried out. The stress–strain diagrams for zones of the joint are received using the original technique for determining coefficients of the “stress–strain” diagram.

In this paper, we present a method for processing an acoustic emission signal using a discrete wavelet transform. The figure shows an example of an acoustic emission signal and strain hardening curve obtained from an aluminum alloy under tensile loading.

Method of CCT diagram plotting based on the numerical analysis of dilatometric tests results. Dependence of the CTE of austenite and its decomposition products from the range of cooling rates clearly defines critical cooling rate and phase transformation ranges.

The study of the iron-containing Bi5Nb3O15 solid solutions has shown that, in the solid solutions iron (III) atoms aggregate with antiferromagnetic and ferromagnetic types of exchange.