Sintered material based on titanium carbide to increase the service life of slide gates

A new cermet material based on titanium carbide with a complex bond consisting of nichrome and nickel, additionally hardened with chromium carbide and a solid solution of chromium in titanium carbide, has been obtained. The influence of the technological parameters of the SHS-extrusion method (the delay time before the application of pressure, the pressing pressure, the speed of the press plunger movement) on the length of the extruded rod is studied, the optimal parameters are found. The microstructure and phase composition of the obtained material was investigated, the physical and mechanical characteristics were measured, and a comparison with analogs was given. It is shown that the microstructure, phase composition, and crystal lattice parameters of the phases do not change depending on the diameter of the extruded rod.

Application of new method in quantum-mechanical calculations of the structural properties and the formation energy of the ordered Mu - phase in the Fe - Mo system

A new technique of finding the minimum total energy, calculated by quantum mechanical calculations, for hexagonal Mu- (μ-) phases of stoichiometric compositions taking into account relaxation, as well as optimized crystal lattice parameters for different compositions in the Fe-Mo system, has been applied. The convergence of the total energy is investigated as a function of the number of plane waves (k) in the range 2000 ÷ 105. Differences in the structural energies between bcc, C14 Laves and μ- phases of pure components, as well as the formation energies of μ- phases of stoichiometric compositions Fe9Mo4, Fe7Mo6 and Fe6Mo7 are calculated.

Synthesis and structural characterization of Fe1-xMexBO3 (Me = Al, Sc) single crystals

Fe1-xMexBO3 (Me = Al, Sc) single crystals have been synthesized by flux growth technique using B2O3-PbO-PbF2 solvent and approach of identical synthesis conditions. The contents of the diamagnetic ions Me in the initial charge of both compositions were equal, xcharge=0.05. The exact contents and crystal lattice parameters of the synthesized crystals were determined by X-ray fluorescence analysis and X-ray diffraction, respectively.

Determination of the crystal lattice parameters based on the fast Fourier transform

In this work, it is shown that the image formed as a result of the passage of coherent radiation through the crystal has certain characteristic features. When the crystal is rotated with respect to the propagation axis of the investigated beam, the formation of the intensity distribution of a complex structure associated with the transformation of the flat image into volumetric was detected at the output. Crystalline plates can be used to form the distribution of a continuous flat light field in the implementation of a real 3D scene, which can provide a three-dimensional image on a television screen, as well as on a computer monitor screen. It can also be used in billboards. The three-dimensional image obtained in this way can be observed directly with the eyes of a person (without using special glasses. Thus, the information capacity of the image on the screen increases, and the perception of the picture approaches real conditions.

Iron nanoparticle influence on the structure of improved structural steel and its properties

The results of the study of the effect of nanoparticles in the shell of iron oxide Fe2O3, which when injected into the melt and heated up to melt temperature is converted into oxide Fe3O4, on the microstructure of hardened and tempered steel 25GSL and its properties. It is shown that in modified steel martensite crystals thickness is reduced compared to the original steel in average 1.9 times after the quenching, tempered martensite crystal length after tempering hardened steel at 200oC - 3 times, the plate cementite length in troostite after tempering hardened steel at 450 оС – 1,4 times, the carbide length of after tempering of steel at 550 оС – 1,6 times. It has been found that modification of iron nanoparticles in a shell of Fe3O4 oxide leads to dispersion of the subgrain structure (regions of coherent scattering) and to the decrease of the crystal lattice parameters of solid solutions. The mechanism of nanoparticle influence on the reduction of the crystal lattice parameters of solid solutions, which is to accelerate the diffusion of interstitial atoms of the elements into the zones of high stress on the nanoparticles surface, is proposed. It is determined that the optimal improvement mode of the modified steel is quenching at 900 °C and tempering at 550 °C. The yield, tensile strengths and toughness of the modified steel are 894 MPa, 993 MPa and 92 J/mm2, respectively, on 62, 41 and 14% higher than the original steel. The injection of iron nanoparticles in a refractory shell into the steel melt before crystallization predetermines the effective modification and enhancement of mechanical properties. Keywords: iron nanoparticles, structure, martensite, troostite, sorbite, carbides, stresses, phase transformations.