Name
Blednova Zhesfina Mikhailovna
Scholastic degree
•
Academic rank
professor
Honorary rank
—
Organization, job position
Kuban State Technological University
Web site url
—
—
Articles count: 11
In modern combine building over the past few years, there has been a trend towards increasing the productivity of machines and, as a consequence, their physical weight. However, as the weight of the combine harvester increases, the necessary condition for its movement in the field in the course of work is to meet the requirements for its support area. As a result, manufacturers have to increase the size and number of wheels of the machine. One solution to this problem is to replace the wheelset of agricultural machines with replaceable rubber track modules. In this case, the very principle of calculation of the main technical characteristics of the engine changes, and if we are talking about the drive axles of agricultural machinery, the calculation methods can be roughly approximated to the calculation of tracked machines with metal tracks. However, in the case of driven axles, there is an intersection in the calculation methods between the classic calculation of the wheel chassis and the calculation of the tracked chassis. The problem is that the tracked chassis are not usually guided like the wheels, so the calculation methods need to be refined by introducing new evaluation criteria because of new power factors in the track module. The article proposes an alternative calculation model to calculate the maximum resistance torque of a track module on a rubber track
The mechanical activation allows creating a active
state in a solid, opening the prospect for holding and
accelerating the chemical reactions between solids and
getting materials in a nonequilibrium state. As a result
of mechanical activation of the powder compositions
of the active phase transformations occur in them,
which lead to the formation of solid solutions and
various intermediate connections, providing dispersion
and dispersion hardening of materials included in the
composition. The results of the study of the
granulometric composition, the phase transformations
and structure evolution in multiphase materials with
SME Ni-30%at.Ti-20%at.Hf and Ni-33%at.Ti-
18%at.Zr at different stages of the process of
mechanical activation carried out in planetary ball mill
the centrifugal type is represented in the article.
During mechanical activation, a composite mix is
assimilated by the particles of processed material input
of mechanical energy in the form of new interfaces,
defects of the crystal lattice. At collision of particles
and grinding bodies in contact high local temperature
and pressure occur, which in some cases can lead to
melting of the most fusible components. When a local
increase in temperature between the particles of
titanium, hafnium, zirconium and carbon solid-phase
reactions become possible due to diffusion of atoms of
one component into the crystal lattice of the other.
Experimental studies have shown that the use of
mechanical activation allows creating an effective
technology of preparation of the starting material for
high-speed flame spraying
The article gives results of research of the process of
abrasive wear of samples made of Steel 45, U10 and
with applied composite surface layer "nickelmulticomponent
material with shape memory effect
(SME) based on TiNi". For the tests we have chosen
TiNiZr, which is in the martensite state and
TiNiHfCu, which is in the austenitic state at the test
temperature. The formation of the surface layer was
carried out by high-speed gas-flame deposition in a
protective atmosphere of argon. In the wear test,
Al2O3 corundum powder was used as an abrasive. It is
shown that the wear rate of samples with a composite
surface layer of multicomponent materials with an
SME is significantly reduced in comparison with the
base, which is explained by reversible phase
transformations of the surface layer with an SME.
After carrying out the additional surface plastic
deformation operation (SPD), the resistance of the
laminated composition to abrasion wear is greatly
enhanced, due to the reinforcing effect of the SPD. It
is recommended for products working in conditions of
abrasive wear and high temperatures to use the
complex technology of formation of the surface
composition "steel-nickel-material with high-temperature EPF", including preparation of the surface
of the substrate and the deposited material, VGN in
the protective atmosphere of argon, followed by SPD
We have performed a mechanical activation of TiNi
powder; as a result, PN47T26TS27 powder after
mechanical activation is flat discs ranging in size
from 10 to 30 microns. We have developed a
composition technology "steel - material with shape
memory effect" by high-velocity oxygen-fuel
spraying of mechanically activated powder based on
TiNi. We have determined the optimal processing
parameters to ensure a nanostructured surface layer.
We have estimated the process parameters of highvelocity
oxygen-fuel spraying. The basic parameters
are: propane flow rate 60-85 l / min, that of oxygen
120-160 l / min, flow rate of powder and carrier gas
(argon), distance and angle of deposition, and
movement speed of the torch, the rotation speed of
the coated workpieces. We have carried out macroand
microanalysis of surface layers of Ti-Ni based
alloy, obtained on proven technology. We have
studied the effect of TiNi doping with a third
component Zr. The simulation allows us to predict
the possibility of using surface modification of
products with SME material TiNiZr under certain
conditions of temperature and to determine the
desired composition of the coating, which provides a
positive effect. We have made tests on steel 45 with
a surface-modified layer TiNiZr under dry friction
conditions, during which there is a significant
increase in temperature, we have confirmed the
effect of improving the wear resistance
The article contains a block diagram of the mechanical
activation process of multicomponent shape memory
materials, taking into account the variety of
influencing factors. We have proposed to evaluate the
reactivity of the sprayed material using the energy
criterion (energy intensity), determined by the
additivity concept as an energy amount of the raw
material and energy accumulated during mechanical
activation. Power consumption of the raw material
depends on the chemical and phase composition and is
determined based on the similarity between the
melting energy, plastic deformation and fracture on the
thermodynamic characteristics and diagrams of the
systems. The energy stored in the MA is determined
on the basis of X-ray structural analysis. We have
demonstrated that with increasing of grinding
precision there is growth in the number of active
centers, which enables nanostructurization of surface
layers in high-velocity oxygen-fuel spraying (HVOF).
According to the study, we have developed practical
recommendations for effective implementation of
mechanical activation of the shape memory material
The article is dedicated to the determination of
conditions for solid bodies’ fragmentation, providing
minimal size of particles by means of their mechanical
dispersion through the example of powders of titanium
carbide (TiC), cubic boron nitride – borazon (CBN)
and boron carbide (B4C). The theoretical and practical
aspects of the process of mechanical fragmentation of
particles of solid powder materials in ball mill for their
further utilization in furnace charge for high-speed
gas-flame sputtering of wear-resistant composite
materials are examined in the article. Methods of
preliminary calculation of minimum allowable size of
solid particles of powder materials during mechanical
fragmentation, based upon Griffiths’ mechanical
theory of rapture using experimental data for hardness
of material and its yield are proposed and theoretically
substantiated. There we have the results of
experiments on mechanical fragmentation of titanium
carbide in attritor, boron carbide and cubic boron
nitride in centrifugal planetary mill, confirming
correctness of theoretical propositions and calculations
are set out. Recommendations on mechanical
fragmentation of solid powder materials in ball mills
are formulated as well
Based on the analysis of the phase composition, the average grain size measured by high resolution electron microscopy and multifractal parameterization structure shows the relationship of coating properties with their structural-phase state. The regularities of the evolution of the structural parameters and multifractal characteristics of the surface layers of materials with shape memory can predict the properties of the composition of the "steel-coating". On the basis of experimental studies, it has been shown that mechanical activation of powders of materials with shape memory effect based on TiNiTa makes it possible to create an effective technology training sprayed material which will generate nano-structured surface layers by high-speed flame spraying. The influence of the mechanical activation of TiNiTa powder on the quality of surface layers formed by high-speed flame spraying was investigated, and a significant improvement in the structure of the surface layer was found, with reduced porosity, high adhesion, and, consequently, increased functionality and mechanical properties. The evolution of the structure at all stages of surface modification based on the fractal approach multifractal parameterization method, which is based on qualitative analysis and instrumental methods in addition to classic microstructure parameters like grain size and specific area related to the physical and mechanical properties, is quantitative information. It was established experimentally that after high-speed flame spraying, the performance characteristics of mechanically activated shape memory TiNiTa powder improved: cyclic durability under high-cycle fatigue increased by about 35.6%, and the wear resistance increased by 3.6 times
A thermal physical and mathematical model of laser cladding with TiNi on steel was developed which allows us to monitor the formation of the structure and the properties of the surface layer. A description of the model included assumptions and simplifications; analysis of the energy balance; numerical modeling of thermal processes; evaluation of the temperature distribution; experimental verification of the obtained solutions. The composition of the steel and TiNi alloy was examined as a two-layer material with different thermal characteristics. The energy balance of the system was described with a heat equation in a three-dimensional form. The main channels of the radiation energy costs were taken into account: absorption surface of the product, loss owed to the reflection surface, energy absorbed by the coating which did not come down to the base material. To solve the differential equation of heat conduction we used the Fourier integral method. In assessing the temperature distribution we have reviewed a dimensional problem when exposed to a point source of the Gaussian distribution in a pulsed mode. Computer calculations used MathCAD graphs of temperature changes at different depths of the TiNi layer and the steel substrate. The results obtained allowed us to develop the recommendations for optimizing the technological parameters of laser cladding of TiNi. The simulation of thermal processes significantly reduces the time and resources required to develop the technology, allowing prediction of the quality of the surface layer during the development of the technology and promoting the adoption of efficient technical and technological solutions
The combined method of formation of the “Steel - superficial of materials with effect of memory of the form on the basis of TiNiCu” composition, which includes mechanical activation of powder, the high-speed gas-flame dusting, the subsequent thermo-mechanical processing is considered. The operating parameters are defined and the optimum modes of processing providing formation of the layers with nano-sized structure are recommended, chemical and phase composition of which corresponds to the shape memory effect
This article presents a complex method of formation of the surface-modified layers of materials with shape memory effect, including high-speed flame spraying powders TiNiCo with a cobalt content of 2 and 5%, subsequent thermal and thermomechanical treatment, allowed forming nanostructured surface layers with a high level of functional and operational properties. It is shown that the TiNiCo complex processing layer allowed reducing the porosity of coatings and increasing the strength of adhesion of the coating to the substrate. Surface modification TiNiCo for optimal regimes allowed increasing fatigue life under high cycle loading by 30-40% and wearing 3-3.5 times. Based on comprehensive research metallophysical surface layers obtained new information on the nanoscale composition