Բանբեր ՀԱՊՀ - Մետալուրգիա, նյութագիտություն, ընդերքօգտագործում

СОВРЕМЕННЫЕ ФИЗИЧЕСКИЕ МЕТОДЫ ИССЛЕДОВАНИЯ МАТЕРИАЛОВ

Г. Р. Дремян — 2018-12-25

Different physical methods of testing and investigating the physical and mechanical properties of materials are studied. The analysis of traditional methods based on a variety of physical phenomena is carried out. As a result, the existing methods are improved, and new methods for testing materials by using the latest achievements in physics and material science are developed. The essence of the above- mentioned methods, the structure and operating principle of the used instruments, in particular, the styloscope and stylometer schemes in the methods of structural and spectral analyses are described. The essence of pyrometers with differential thermocouples in the thermal analysis method; the device for radiographic analysis; the magnetic flow detector with induction actions in the ponderomotive method with magnetic analysis for establishing the presence of internal defects in details; the ultrasonic flow detector,
as well as the scheme of ultrasonic pulse reflective flow detector; the structure and principle of operation of an inductive tensometer for measuring deformations in tensometry are also considered. The essence of the polarization-optical method of investigation, the advanced method of electrical modeling, the method of X-ray flow detection, in particular the X-ray interferometric method of image interpretation of defects, the method of double three- and four-crystal interferometers, triple three- and four-crystal interferometers are described. It is shown that interferometric topographic patterns depend on the orientation of the reflecting planes, the unambiguous interpretation of the image of the defects is greatly facilitated when interferograms are obtained with the help of multiple interferometers, and multiple interferometers give a more complete description of the deformed state of the crystals. It has been experimentally proved that interferometric patterns obtained from the same crystal with the help of families of symmetrically equivalent planes will be the same only in the case when
the crystals of the interferometer are ideal. It is shown that in a four-block interferometer pairwise imposition of diffracted beams leads to three different moire bands in contrast, and when three beams are imposed, the contrast of moiré patterns is greatly reduced.

ТЕРМОДИНАМИЧЕСКОЕ ОБОСНОВАНИЕ ПРОЦЕССА СУЛЬФИДИРОВАНИЯ ОКИСЛЕННЫХ МЕДНЫХ МИНЕРАЛОВ СЕРОЙ

А. В. Авагян — 2018-12-25

Investigation of the methods for hard-to-beneficiate and mixed ore processing is currently the main scientific and technical challenge in non-ferrous metallurgy. High-temperature sulphidation of oxidized copper minerals in practice is rather complicated, economically is not profitable, therefore only low- In the Teghut mine, a zone of oxidized copper rocks with a relatively rich mineralization is distinguished. In the oxidized zones, there are copper minerals: tenorite - CuO, cuprite - Cu2O, azurite - Cu3(OH)2[CO3]2, malachite-Cu2(OH)2[CO3], and also, in limited quantities, turquoise - CuAI6 (OH)8[PO4]4.4H2O. When beneficiating such copper minerals, a more acceptable type of surface activation is the process of mechanical activation in combination with adding reagents. The method of the deep sulphidation of the surface of oxidized ore minerals with the given physical and chemical properties is based on the distortion of the crystal structure of the ore. The influence of the mechanical energy on the crystal structure increases the number of defects and, affecting the process of structural and chemical transformations, the process of sulphidation takes place in the sulphuric environment, which reduces the degree of defectiveness and internal energy. The degree of imperfection of minerals affects flotation. To determine the probability of the interaction reactions of oxidized copper minerals with sulphur, thermodynamic calculations were initially carried out. As a criterion for the reaction under conditions of constant pressure and temperature, the Gibbs energy lowering theory G was adopted. The Gibbs energy was calculated by the Temkin-Schwartzman method of redox reactions at temperatures K: 308, 318, 328, 338, 348. In order to obtain comparative data, calculations were performed for 1 mole of sulfidization. A thermodynamic calculation was first used to substantiate the technological process of deep sulphidation of Teghut oxidized copper minerals on the surface, which is carried out in the processes of grinding and crushing azurite, malachite, cuprite and tenorite in the presence of sulphur. It was shown that the interaction occurs with a large negative value of the energy of Gibbs, which is necessary to obtain copper sulphides for further flotation.

ПОЛУЧЕНИЕ МАХ-ФАЗ В СИСТЕМЕ TI-AL-C МЕТОДОМ САМОРАСПРОСТРАНЯЮЩЕГОСЯ ВЫСОСКОТЕМПЕРАТУРНОГО СИНТЕЗА И ИССЛЕДОВАНИЕ ИХ СОСТАВА И МИКРОСТРУКТУРЫ

В. А. Мартиросян — 2018-12-25

A typical representative of the MAX phases is Ti3AlC2. However, the currently existing methods of obtaining materials based on MAX-phases are far from being perfect. These metods are characterized by significant power consumption, complexity and multistage technological cycles, low productivity and do not always provide the required quality of materials according to structure and properties, as well as - purity. Based on the abovementioned it is required to create and develop new methods and technologies for their production. In this work, the synthesis of Ti3AlC2 from the Ti-Al-C powder mixture was carried out by the SHS method in the combustion regime. The effect of the amount of carbon on the phase formation process was studied. The XRD analysis showed that the product obtained is multiphase and consists, in addition to the main phase, of the intermetallic phases Al3Ti, AlTi and Al5Ti2. It was found that at the aluminum content of 20 and 25%, all aluminum participates in the formation of the MAX phase, and the remaining titanium and carbon form a TiC compound. At 30% of the aluminum content, excess aluminum which does not participate in the formation of the MAX phase, forms an intermetallide Al3Ti with titanium. Thus, it is shown that Ti3AlC2, with a total MAX phase content of 94,9%, and TiC content not exceeding 5,1% can be obtained from the TiS-Al-C powder mixture by the SHS method. Micrographs show that with an increase in the amount of aluminum, the structure of the MAX phase becomes more porous. On the contrary, with an increase in the amount of titanium, the structure becomes more dense.

ПОЛУЧЕНИЕ ВЫСОКОКАЧЕСТВЕННЫХ ПОРОШКОВЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ МЕТОДАМИ ПОРОШКОВОЙ МЕТАЛЛУРГИИ

Л. З. Галстян — 2018-12-25

In difficult operating conditions, the use of powder can be achieved only when its absolute density is achieved in the case of elimination of all types of porosity. Isostatic concentration and hot isostatic molding are partially the most promising methods for condensation of irregularly stretched powders or cold-pressed particles. In the case of simultaneous exposure to temperature and pressure for almost all solid materials, 100% or similar density can be achieved. Another method of obtaining absolute density provides hot or cold pressing after intermediate preparation of the powder. The possibility of using hot extrusion of the synthesis of powder composite materials on a metal basis is substantiated. Extrusion provides a non-porous structure and combines the processes of extrusion and clumping, and the high velocities of molding completely eliminate the negative interaction of the matrix and the hardening phase. The mechanisms and kinetics of compaction, as well as the processes of structure formation of composite materials and high mechanical properties are revealed. The creation of materials and products with a non-porous structure is a fundamental direction in the field of powder metallurgy. Porosity is a discontinuity, i.e. structural defect, which not only significantly reduces the strength properties of the composite material, but also accelerates corrosion and ageing. At hot extrusion, maximum degrees of deformation are achieved ( =60...90%), whereas with static and dynamic pressing, they do not exceed 15 ... 20%. In addition, the extrusion process is characterized by shear plastic deformations caused by the action of deviator stresses.

АНАЛИЗ ДВИЖЕНИЯ ВОЛОКНИСТОГО МАТЕРИАЛА В ФОРМИРУЮЩЕМ БУНКЕРЕ

С. А. Кюрегян — 2018-12-25

An experimental method for analyzing the movement of a fibrous material in a forming bunker of a two-chamber hopper feeder at processing fine-fiber cotton is proposed. It is shown that in spite of somewhat increased unevenness of the carding tape with impoverished feeding, the quality of the semi-finished products along the transitions in the compared variants is equalized. The level of breakage, and the physical and mechanical properties of the yarn in the control and test versions differ little. The tests carried out proved the absence of a negative effect of the lack of energy of the carding machines on the technological process in the system of combed spinning of cotton. It is also proved that for the stability of the feed process, it is necessary to conduct research on the use of means that allow to reduce the magnitude of the phenomenon of the cotton hanging between the walls of the forming bunker at the minimum width of it. It has been experimentally proved that at a large width of the forming bunker, a significant compaction of cotton falls on its lower part before entering the clamping zone of the outgoing rollers which will force out the layers of cotton of its total weight supported by these rollers. Based on the analysis of the results of the experiments, it can be concluded that as the filling level of the cotton bunker increases, the density of the fiber increases. In the paper, it is shown that in the general case, the different values of the height of the sections with constant density in the lower part of the hopper cause the fiber density to fluctuate with different loosening effects in the sorting and trebling workshop and fluctuations in the filling level of the hopper with cotton. Therefore, in order to ensure a uniform planking of the fibrous material on the feeding table of the machine, it is necessary to ensure a stable density of the pulp on the largest possible portion of the forming hopper in front of the fiber zone by the outgoing rollers.

ИССЛЕДОВАНИЕ ИСТИРАЕМОСТИ СМЕШАННЫХ ТКАНЕЙ РАЗЛИЧНОГО ВОЛОКНИСТОГО СОСТАВА

З. А. Минасян — 2018-12-25

The effect of the fibrous fabric of mixed fabrics on their abrasion is studied. As the object of the study, samples of "cotton + polystyrene" samples of 0,155 10-3m thick "cotton + viscose" and 0,183 10 -3m and 0,33 10 -3m were selected with a different percentage of components. Experiments have been made on the FD-17A device, which is intended for detecting the staining resistance to the substrate by using crushed stone which does not contain sandpaper and synthetic fibers. The abrasion of the samples having the dimensions (60 210) 10 -3m have been determined by the number of cycles fixed by the device meter at each of the three phases of the abrasion meter: formation of collars, fibrous fractures and holes in specimens. 10 samples were prepared for each fiber composition of the investigated types of blend fabric, 5 of which were tested using abrassive paper, and 5- using grey cloth. The data on abrasion for 5 samples were averaged. The worked sandpaper and grey cloth were regularly replaced by new ones. The results of experimental study of abrassion of mixed fabric samples have shown that
the fiber composition of the samples, and their thickness have a great impact on them. In case of decrease in the cotton content percentage and the increase in the percentage of viscose or polyester for "cotton + viscose" and "cotton + polyester" samples, their depreciation decreases in all three stages of the simple abrasion in case of using both sandpaper and grey cloth. The increase in the thickness of the " cotton + polyester " mixed fabric samples results in reduced
abrasion for all fibrous compositions and in all the three stages of abrasion at using sandpaper and grey cloth.

ИССЛЕДОВАНИЕ ГИДРОФОБНОЙ ОБРАБОТКИ КОЖИ СРЕДНЕВЕКОВЫХ КНИЖНЫХ ПЕРЕПЛЕТОВ МЕТОДОМ ОКАНЧАТЕЛЬНОЙ ОТДЕЛКИ ПЛЕНКООБРАЗУЮЩИМИ И ВОДОСТОЙКИМИ МАТЕРИАЛАМИ

Г. А. Элиазян — 2018-12-25

We have previously researched the effect of biocide products on the growth of several fungi-mycodestructors. We know that ancient leather bindings did not go through finishing phase or even if the leather did receive coating, then natural lubricating substances were used. That type of finishing could not provide enough water resistance to the leather. Water resistance of leather is determined by the following factors: a) By the water repellency of the surface of the leather, as well as fibers of the dermis and the layer of leather located near the front flesh side of a hide surface; b) By the fiber swelling (water quickly penetrates the leather, but the fibers as they swell, they fill the interstructural gaps of the dermis and the further absorption of water by the dermis stops). To reduce the water permeability of the leather, it is not enough to cover its fibers with a water-repellent film. This is explained by the fact that the hydrophobic leather will remain
water resistant only until it undergoes various deformations (bending, pressure). Despite this fact that book bindings rarely get bent, they are often subject to various deformations under pressure. This factor explains the development of technology for producing water resistant leather. Continuing the research on conservation and preservation of medieval leather bindings of The Matenadaran Museum, in order to expand the use of natural oils and their modifying agents, an attempt was made to improve the method of greasing with the help of fat-organic mixtures. For the final finishing of ancient leathers, various binders (resin) and hydrophobic interaction of the siloxane with the film-forming binder was studied as well. The latter, as a well-known hydrophobic film former, was tested for the final finishing of ancient leather and experiments showed that its use significantly increased the leather resistance to water.

ОБОСНОВАНИЕ ОПТИМАЛЬНЫХ КОНТУРОВ КАРЬЕРА ПРИ ЭКСПЛУАТАЦИИ КАШЕНСКОГО МЕДНО-МОЛИБДЕНОВОГО МЕСТОРОЖДЕНИЯ

А. Г. Оганесян — 2018-12-25

The substantiation problem of the optimal contours of the Kashen copper-molybdenum open-pit, functioning on the basis of the ore of the eponymous copper-molybdenum mine is considered. This deposit is located in Republic of Artsakh and is represented by oxidized, altered and secondary oxidized zones. According to the morphology, the Kashen copper- 0 . The development of economic-mathematical models for determining the optimal boundaries of open works for the given mine under different scenarios of world metal prices is very relevant, since the ore reserves in the bowels, on the basis of which the mining enterprise is projected, depend on the limits of the content of useful components, the magnitude of which is directly proportional to the specific incremental costs of extraction and processing of ore, and inversely proportional to the metal prices. The economic-mathematical models, depending on the price of 1 ton for refined copper (Pm=3,000 $/ton, Pm=5,000 $/ton, Pm=7000 $/ton), where the profit of Kashen mining and processing plant for the weight of the life of the deposit is chosen as the optimality criterion are made up. The patterns of the exploatation ore reserves and the stripping ratio change are revealed based on the area of the bottom of the open-pits under different scenarios of the world prices of copper. The respective nomograms have been constructed. It is determined that the optimal contours of open-pits, all other things being equal, depend on the actual content of the useful component in the ore massive, the extraction ratio of
the mineral from the bowels and the exploitation stripping ratio. The development of the Kashen copper-molybdenum deposit is most appropriate to be
carried out by an open-pit with an outer breading as by expanding the area of the open-pit bottom the exploitation ore reserves is higher than the increase of the exploitation stripping ratio.