Barothermal Treatment Research Articles

Effect of oversolidus barothermal treatment on the microstructure and properties of binary hypereutectic Al-Cu alloys

This study investigates the effect of oversolidus barothermal treatment (BTT) on microstructure and properties of binary alloys Al-22Cu and Al-27Cu (at.%), focusing on the pressure-induced shifts in solidus and liquidus temperatures. The pressure shift of the solidus and liquidus temperatures was established at a hydrostatic argon pressure of ~ 100 MPa using the differential barothermal analysis (DBA). The solidus temperature of both alloys increased by approximately 8 ℃ during heating, aligning closely with the equilibrium state diagram upon cooling. The liquidus temperature of the alloys at 100 MPa increased by 11 ℃ for Al-22Cu and by 14 ℃ for Al-27Cu compared to the phase diagram. Taking these results into account, barothermal treatment of the alloys was carried out at 100 MPa and 570 ℃ for 240 min (BTT1), as well as at 100 MPa and 562 ℃ for 10 min (BTT2). Processing of alloys at BTT1 leads to the primary Al2Cu particle size significant increase to lengths of 350–1500 μm and widths of 150–400 μm. During BTT1, the structure of the initial lamellar eutectic Al-Al2Cu is modified with the formation of discrete intermetallic particles, with the length and width being 15–240 and 1–3 µm, respectively. With a decrease in temperature and exposure time, a significantly less intense increase in the size of primary intermetallic compounds occurs, and a noticeable increase in discrete eutectic intermetallic compounds occurs. The microhardness reached 2043 MPa for the eutectic (initial Al-22Cu). For the intermetallic and the eutectic, the microhardness was 4189 and 2699 MPa, respectively (initial Al-27Cu); for intermetallic and the eutectic 4754 and 1382 MPa, respectively, for the Al-22Cu alloy processed at BTT1, and the eutectic microhardness for the Al-22Cu composition processed at BTT2 was 2409 MPa. The bending strength of alloys decreases after oversolidus BTT.

Dependence of the Lattice Parameters and Heat Resistance of an Ni-Based Alloy on Heat and Barothermal Treatment Conditions

Dependence of the Lattice Parameters and Heat Resistance of an Ni-Based Alloy on Heat and Barothermal Treatment Conditions

Influence of Temperature in Barothermal Treatment of Sintered Cemented Carbides on the Evolution of Their Structure and Properties

Influence of Temperature in Barothermal Treatment of Sintered Cemented Carbides on the Evolution of Their Structure and Properties

Thermal Analysis, Barothermal Treatment, Microstructure, and Properties of an Al–2.5 at % Ca Binary Alloy

Thermal Analysis, Barothermal Treatment, Microstructure, and Properties of an Al–2.5 at % Ca Binary Alloy

Thermal and Barothermal Treatment, Microstructure, and Properties of an Al–8Si–3.5Cu–0.2Mn Alloy

Thermal and Barothermal Treatment, Microstructure, and Properties of an Al–8Si–3.5Cu–0.2Mn Alloy

Optimizing the use of protein in the young cattle body

The organization of complete feed rations for cattle meeting the needs of animals in energy, protein, amino acids, minerals and vitamins in terms of basic nutrients and biologically active substances represents the main condition to achieve the genetic potential of productivity. The purpose of the paper was to optimize the protein utilization in the body of young cattle by synchronizing the processes of fermentation of nitrogen-containing substances and carbohydrates in feed. Barothermal treatment of concentrated feed mixtures with high protein degradability and a high content of non-structural carbohydrates causes a more uniform fermentation of nutrients, intensification of microbial protein synthesis processes and an increase in the efficiency of energy use of carbohydrates and protein nitrogen by rumen microflora. This is evidenced by an increase in the number of ciliates by 4.4–8.1% and a decrease in the concentration of ammonia and volatile fatty acids in the rumen fluid by 5.2–.2% and 3.4–4.3 %, respectively. A decrease in nitrogen losses is indicated by a decrease in the content of urea in animals’ blood by 2.0–9.0%. Extrusion of concentrated feeds with high protein degradability and high content of non-structural carbohydrates improves animal productivity and feed efficiency. The average daily gain in live weight increases by 4.8-6.0% in the experimental group. As a result, feed consumption is reduced by 2.7-6.9%, while protein consumption is reduced by 2.6-5.7%.

Microstructure and Physical and Mechanical Properties of the Al90Gd10 Binary Alloy after Barothermal Treatment

Microstructure and Physical and Mechanical Properties of the Al90Gd10 Binary Alloy after Barothermal Treatment

Efficiency of expanded compound feed application for broiler chickens

The intensification of animal husbandry is accompanied by an increase in demand for high-quality compound feed, which largely determines the level of development and economics of animal husbandry, especially industrial, specialized livestock farms. Reducing feed costs is one of the key challenges. Its solution is impossible without the rational use of grain and other raw materials, the introduction of modern innovative technologies and equipment at feed mills. Barothermal treatment of the grain mixture in the expander reduces bacterial contamination, completely destroys coliform bacteria, E. coli, mold fungi and salmonella. The technology for the production of expanded feed for broiler chickens was developed in the course of the work. Broiler chickens of the Smena 7 cross were used as the object of the study. It was found that the chicken palatability of the expanded compound feed developed with the help of the optimization program "Korm Optima Expert" improved and at the age of 28 days their live weight increased by 2.5–3 times in groups, chickens that received grits from granular expandate having the highest indicator (915 g). At the end of the experiment 42-days old chickens of the control group had a live weight of 2246 g, and the chickens that received granulated expandate - 2574 g. The average daily gain in live weight of chickens was 66.4 g, which is 7.9% higher than in the control group. The results of the control slaughter of chickens showed an increased yield of meat in chickens treated with expanded pellets (69.5%) compared to the control (67.6%). The best indicators of the productivity of broiler chickens of the Smena 7 cross were obtained when feeding compound feed in the form of grains from granulated expandate in the first period of cultivation and granulated expandate in the second period of cultivation.

Influence of extrusion on the feed value of flax seeds

Relevance. The wide use of extrusion for processing plant raw materials is explained by the possibility of improving the structure and increasing the availability of macronutrients of the target product. Extrusion of oilseeds is complicated by the negative effect of high lipid content on the ongoing physicochemical processes and, as a consequence, a decrease in the quality of extrudates. Along with their high lipid content, oilseeds such as flaxseed contain significant amounts of protein, soluble (mucilage) and insoluble (cellulose, lignin) fibers, which can also affect the technological properties of extrudates. As a high-energy and protein component, flax seeds are used in the feed industry. Increasing the nutritional value of flax seeds and their safety will expand the range of biologically active additives for the production of feed. The purpose of this work is to study the effect of extrusion on the feed value of flax seeds.Methods. For the research we used unmilled oil flax seeds produced in 2020. Flax seeds were processed by wet extrusion: the raw material was preliminarily moistened to 17% at 80 °C; extrusion process parameters — 120 °С, pressure 40 atm., duration 30 sec. Extruded flax seeds were obtained on a pilot plant of OOO “Fid-Group” (Belgorod region). Studies of extruded flax seeds were carried out on the basis of the laboratory for processing bast crops of the Federal Scientific Center for Fiber Crops (Tver).Results. A comparative analysis of the results showed a positive effect of short-term barothermal treatment, such as extrusion, on the chemical composition of flax seeds and their feed parameters. It has been shown that: the content of crude protein in extruded flax seeds increased by 3.97%, the water-soluble fraction increased by 66.18%, which indicates an increase in the biological value of the extrudate; the mass fraction of crude fiber decreased by 1.18%, which indicates an improvement in the digestibility of the extruded product; the content of mineral nutritional value increased by 12.5%; when using barothermal treatment, the nutritional value of flax seeds increased by 2.46%, metabolic energy increased by 2.19% and digestible protein increased by 4.08%; the level of indicators of the lipid complex, acid number and peroxide number, decreased by 40 and 39% respectively, which indicates a decrease in the activity of enzymes that cause hydrolytic and oxidative deterioration of the extrudate.

Effect of synchronization of fermentation processes in body of young cattle

Indicators of rumen digestion of young cattle has been studied when fed with concentrates with high level of degradable protein and non-structural carbohydrates subjected to barothermal treatment. Extrusion of concentrated feed decreases degradability of concentrates protein by 26-28%. Correlation of indicators of rumen digestion in steers with the method of preparation for feeding with concentrates with high level of degradable protein and non-structural carbohydrates has been determined. So, in animals receiving feed subjected to barothermal treatment, the number of ciliates in rumen fluid increases by 5.4%, total nitrogen – by 2.9%, and concentration of ammonia and volatile fatty acids decreases by 8.1 and 3.4% Thus, processing of concentrates stimulates development of microflora of proventriculus and reduces the rumen protein loss. Barothermal treatment of concentrates with a high protein degradability and high level of non-structural carbohydrates increases productivity of animals and efficiency of feed. The average daily weight gain in animals of experimental group increases by 4.8-6.0%. As a result, the feed cost is reduced by 2.7-6.9%, and protein – by 2.6-5.7%.

Barothermal Treatment, Cold Plastic Deformation, Microstructure and Properties of Binary Silumin Al–8 at % Si

Barothermal Treatment, Cold Plastic Deformation, Microstructure and Properties of Binary Silumin Al–8 at % Si

Структурные особенности композиционных материалов из гидролизованной древесины березы

Structural features and physical and mechanical characteristics of plate composite materials are investigated. The materials are obtained from hydrolyzed birch wood by hot pressing without the addition of binding components. Wood processing is carried out by the method of explosive autohydrolysis without chemical reagents. The influence of pre-moistening of wood on the structure and properties of the composite material is studied. The structural features of the amorphous and crystalline components of the composite material are studied. It was found that the composite material obtained from pre-dried and pre-moistened wood retains the crystalline phase that is present in the original wood. Changes in the structure of wood when obtaining composite materials based on it occur in the amorphous component. Based on the temperature dependences of the dynamic shear modulus and the tangent of the angle of mechanical losses, information on the glass transition temperature of a complex of amorphous components of a composite material is obtained. It was found that the region of transition of lignin and hemicellulose macrochains from a glassy to a highly elastic state in the composite material is shifted towards low temperatures in comparison with the original wood. The offset is more than 70K. It is assumed that structural plasticization is the main cause of the detected effect. Pre-moistening of wood does not affect the position of the temperature transition in the amorphous component of the composite material. The study of the diffusion and sorption of water vapor in the samples of the material shows the presence of large structural inhomogeneities. Diffusion processes obey Fick’s second law and correlate with the density of samples. Data on density, static bending strength, water absorption and swelling characteristics of composite material samples were obtained. It is shown that the use of pre-moistening of wood before barothermal treatment significantly improves the structural uniformity of the resulting material. The value of the dynamic shear modulus at room temperature in comparison with the same indicator for the material obtained on the basis of dry wood increases three times. Mechanical losses are reduced, mechanical strength increases.

Физико-механические характеристики термодревесной композиции из древесины сосны при баротермической обработке

The studies are aimed at forming ideas on the structure and properties of composite materials obtained from pine wood and the processes occurring in the structure of wood tissue. The article presents the data on the influence of the conditions of barothermal treatment of pine wood samples by the method of explosive autohydrolysis on the properties of a thermowood composition. The composite material is obtained by hot pressing. The influence on density, strength and hydrophobic characteristics was studied. A series of samples was made under different conditions of the explosive autohydrolysis rigidity factor; at a temperature of 200 °C and the process duration from 0.08 to 10 min. All samples of composite material were obtained without the use of additional components. It was found that the increase in the hydrolysis rigidity factor leads to a decrease in the density of hydrolyzed wood from 440 to ~350 kg/m3. There is no fragmentation of wood samples with the selected processing parameters. Hot pressing of hydrolyzed wood obtained under conditions of low or moderate rigidity is accompanied by a linear increase in the density of the thermowood composite material from ~440 to 500 kg/m3. The consequence of a further increase in the rigidity factor is a slowdown in the rate of increase in the density of the composite material. The conditional boundary that determines the achievement of the maximum number of cross-linked intermolecular structures in the composite material corresponds to the rigidity factor of 3000–4500 min. More rigid processing conditions cause intensification of thermal degradation processes. The dependence of hydrophobic characteristics on the rigidity of the barothermal treatment conditions is complex. At the rigidity factor of 1000–3000 min, an extreme point is observed, before which the hydrophobic properties of the material deteriorate. Its water absorption and swelling increase from 50 to 130 % and from 15 to 54 %, respectively. The hydrophobic performance is significantly improved after reaching the extreme point. Water absorption and swelling reduce to ~20 % and ~10 %, respectively. Mild hydrolysis conditions do not result in a material with consistently high hydrophobic properties. The cross-linked structures are not enough to form a strong and water-resistant composition, and as a consequence, the hydrophobic characteristics deteriorate. Increasing the value of the hydrolysis rigidity factor increases the number of active components. Additional intermolecular bonds formed during pressing improve hydrophobic characteristics. The obtained results can be used in the creation of models of processes occurring in the structure of lignocellulose substance during explosive autohydrolysis and in the preparation of composite materials based on it. Optimal parameters of barothermal treatment for obtaining composite materials with specified physical and mechanical characteristics can be determined. Barothermal treatment of solid pine wood by explosive autohydrolysis contributes to the occurrence of chemically active components in the structure of wood tissue. Their number depends on the rigidity of the processing conditions. The properties of the resulting thermowood composition depend on the conditions of explosive autohydrolysis.

Physical and mechanical characteristics of a composite material made of birch wood hydrolyzed in the presence of hydrogen peroxide

The results of research of physical and mechanical characteristics of the plate composite material obtained from birch wood after its processing by the method of explosive autohydrolysis are shown. Before barothermal treatment, the wood was impregnated with an aqueous solution of hydrogen peroxide. The composite material is made from hydrolyzed wood pulp by hot pressing without adding binders. It was found that the properties of the composite material depend on the amount of hydrogen peroxide and the rigidity of the barothermal treatment conditions. Each of the modes of barothermal treatment corresponds to a certain value of the amount of hydrogen peroxide, when using which the density of the material reaches the maximum value. The dependence of the bending strength of a composite material obtained using different amounts of hydrogen peroxide is characterized by the presence of an extremum point. At this point, the strength value is the maximum. Further increase in the amount of hydrogen peroxide is accompanied by a deterioration in strength characteristics. It is suggested that the effect is a consequence of the dominance of destructive processes over the processes of intermolecular crosslinking when using a large amount of hydrogen peroxide.

Process Efficiency and Energy Consumption During the Extrusion of Lignocellulosic Materials

Lignocellulosic raw material is the main substrate used in agricultural biogas plants. They become usable after proper preliminary treatment, part of which is the extrusion-cooking process. The aim of this work was to determine the efficiency and energy intensity of the process of extrusion-cooking of lignocellulosic materials under varied barothermal treatment conditions. Generally available vegetable raw materials were used for the study: maize bran, maize straw, lignified grass hay, and wheat straw. The extrusion-cooking process was performed with the TS-40 single-screw extruder by Metalchem Gliwice equipped with a plasticizing system of L/D = 12. Four levels of moistening were applied for raw material mixes (20, 25, 30 and 35% of dry matter) and three rotational speeds for the extruder screw (70, 90 and 110 rpm). The level of moistening of the raw material and changes to the extruder screw speed had an appreciable impact on the course of raw material processing. The top process efficiency was recorded for maize bran (50.40 kg h−1) treated at the extruder screw speed of 110 rpm and 30% of the level of moisture, and the lowest (11.22 kg h−1) for grass hay with 20% of the level of moisture and the extruder speed of 70 rpm. The lowest energy intensity indicator (0.093 kWh kg−1) was reported for maize bran processed at the screw speed of 70 rpm and a moisture content of 30%. The highest energy intensity indicator of the extrusion-cooking process, i.e. 0.37 kWh kg−1, was seen in maize straw and wheat straw at a moisture content of 20% and the screw speed of 110 rpm.

Physical and mechanical characteristics of the thermal-wood composition from hydrolyzed birch wood

The article presents data on the influence of the conditions of barothermal processing of downly birch (Betula pubescens) wood and its hot pressing on the physico-mechanical properties of the resulting thermo-wood composition. Steam treatment is performed at a temperature of 200° C, the duration of the exposure time in the reactor is from 5 to 600 seconds. Dried samples of hydrolyzed wood were subjected to hot pressing at a temperature of 120 or 140 ° C under pressure of 4.0 and 5.3 MPa. It has been established that an increase in the hardness factor of hydrolysis is accompanied by an increase in the density of the obtained samples of the thermo-wood composition. The dependence of the strength characteristics on the rigidity of the conditions of barothermal treatment is complex, determined by the presence of a point of extremum, after which the strength characteristics begin to decrease. Based on the obtained results, the optimal conditions for obtaining the thermo-wood composition were determined. It is shown that barothermal treatment of birch wood with the purpose to obtain on its basis a thermowood composition with optimal physicomechanical characteristics is expedient under the conditions of a process stiffness factor of 2000. .. 2500 minutes.

The Technology for Manufacturing HighStrength Pipe-Concrete Bearing Elements to Increase the Stability of Underground Structures

It is proposed to use high bearing small-size pipe-concrete units in the construction of underground geotechnical structures instead of large-sized reinforced concrete units (support blocks, pylons, columns, etc.). The analysis of the methods of manufacturing pipe-concrete units, their advantages and disadvantages is conducted. The process flowchart for manufacturing pipe-concrete units with barothermal pre-stressing of a concrete mixture in a steel pipe was developed to ensure the collaboration of a steel pipe and a concrete core and increase its strength. Experimental research in barothermal treatment of a concrete mixture in a steel pipe was performed using the laboratory model of a pipe-concrete unit, which showed the efficiency of the proposed technological scheme for the production of pipe-concrete units. The lines for further research in the development of a method for determining the optimal parameters of the technological scheme for manufacturing pipe-concrete units with barothermal pre-stressing of a concrete mix are planned.

Influence of High Pressure and Temperature on the Structure and Properties of the WC–6Co Hard Alloy

The results are presented of the barothermal treatment studies of a WC–6Co hard alloy at high pressure (7 GPa). It is shown that such a treatment of hard alloy leads to the deterioration of the basic physico-mechanical characteristics, specifically the strength at the contact, and the coercive force, which is stipulated by the increase of the defects amount in the structure of the carbide phase of the hard alloy.

Effect of Barothermal Treatment on the Structure and the Mechanical Properties of a High-Strength Eutectic Al–Zn–Mg–Cu–Ni Aluminum Alloy

The effect of barothermal treatment by hot isostatic pressing (HIP) on the structure and the properties of castings of a promising high-strength cast aluminum alloy, namely, nikalin ATs6N4 based on the Al‒Zn–Mg–Cu–Ni system, has been studied using two barothermal treatment regimes different in isothermal holding temperature. It is shown that the casting porosity substantially decreases after barothermal treatment; eutectic phase Al3Ni particles are additionally refined during exposure to the barothermal treatment temperature: the higher the HIP temperature, the more substantial the refinement. The improvement of the casting structure after HIP increases their mechanical properties. It is found, in particular, that the plasticity of the alloy in the state of the maximum hardening increases by a factor of more than 8 as compared to the initial state (from 0.82 to 6.9%).

Growth of high optical quality zinc chalcogenides single crystals doped by Fe and Cr by the solid phase recrystallization technique at barothermal treatment

The method of growing of ZnS and ZnSe single crystals doped with chromium and iron using a combination of the solid phase recrystallization and diffusion doping during the high-temperature gas-static pressing has been implemented. The isostatic pressing up to 110MPa has made it possible to increase the process temperature up to 1300°C, increase the rate of grain growth and diffusion of Fe2+ and Cr2+ ions in zinc chalcogenides crystalline samples, reduce processing time to 25–150h. ZnS:Cr (Fe) and ZnSe:Cr (Fe) single crystals from several to tens mm in size with dopant concentrations of (1–5)×1019cm−3 for Cr2+ and (5–20)×1018cm−3 for Fe2+ and at the total impurity's content no more than 5×10−4wt% have been obtained. The lasers made from the crystals demonstrated 55% differential lasing efficiency for the absorbed power.