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This paper aims at the phase identification and quantification in transformation induced plasticity duplex stainless steel (TDSS) base and weld metal containing ferrite, austenite, and martensite. Light optical microscopy (LOM) and electron backscatter diffraction (EBSD) analysis were employed to analyze phases. Samples were either mechanically or electrolytically polished to study the effect of the preparation technique. Mechanical polishing produced up to 26% strain-induced martensite. Electrolytic polishing with 150 g citric acid, 300 g distilled water, 600 mL H3PO4, and 450 mL H2SO4 resulted in martensite free surfaces, providing high-quality samples for EBSD analysis. Martensite identification was challenging both with LOM, due to the similar etching response of ferrite and martensite, and with EBSD, due to the similar lattice structures of ferrite and martensite. An optimized Beraha color etching procedure was developed that etched martensite distinctively. A novel step-by-step EBSD methodology was also introduced considering grain size and orientation, which successfully identified and quantified martensite as well as ferrite and austenite in the studied TDSS. Although here applied to a TDSS, the presented EBSD methodology is general and can, in combination with knowledge of the metallurgy of the specific material and with suitable adaption, be applied to a multitude of multiphase materials. It is also general in the sense that it can be used for base material and weld metals as well as additive manufactured materials. This study received support from the EU-project H2020-MSCA-RISE-2018 Number 823786, i-Weld, and the Swedish Agency for Economic and Regional Growth through the European Union–European Development Fund

The present study investigated the effect of mechanical alloying (MA) time, preheating and annealing process on phase and microstructural transformations in Al65Cu23Fe12 (at%) alloys. To release stresses, a part of milled powder was heated at 150 °C for 20 min and then raw compacts of the as-synthesized powders and preheated ones were prepared and heated at selected temperatures from 200 to 800 °C using microwave radiation. The results showed that with increasing the time of mechanical alloying process, the morphology of the particles changed and nanometer spherical particles were formed. Also, β-Al(Cu,Fe) solid solution phase was formed after 16 h of mechanical alloying. After 30 h of mechanical alloying, the quasi-crystalline phase did not form directly under the conditions employed in this work. Comparison of preheated samples with samples without preheating process showed that the quasi-crystal phase was formed at 300 °C for preheated samples, while the β phase was formed for samples without preheating process. The results of phase analysis also showed that β-Al(Cu,Fe) and θ-Al2Cu phases along with the quasi-crystalline phase are the main phases in the samples. The annealing process of the samples using microwave radiation leads to the formation of a quasi-crystal phase at temperatures and times much lower than other annealing methods.

Self-propagating High-temperature Synthesis (SHS) process is used to prepare Aluminium dodecaboride (AlB12). The phase analysis results of preparing AlB12 with Al and B2O3 as raw materials show that under air and argon conditions, the self-propagating and acid-washed self-propagating powders all have α-Al2O3 impurities when Mg, Al and B2O3 are used as raw materials. The phase analysis results of the preparation of AlB12 show that under argon conditions, the self-propagating and acid-washed, self-propagating powder has un-removable MgAl2O4 impurities, and the root cause of the low purity of AlB12 prepared by the self-propagating method is the presence of un-removable impurities.

The present work deals with the microstructure, nanoindentation and wear behaviour of Inconel-718 (IN-718) specimens fabricated through laser-powder bed fusion (L-PBF). To ensure the improvement in...

Indefinite-chill materials are used as shell materials for cast work rolls for surface-critical applications in hot rolling mills. Besides a smooth surface quality, a low sticking tendency and low sensitivity against incidents in the rolling mill, the work rolls need the highest wear resistance possible. The microstructure of the indefinite-chill material consists of various carbides (cementite up to 40 area-%) and up to 5 area-% of graphite embedded in tempered martensite. To increase the wear resistance of this material group, the comparably soft cementite has to be replaced by more wear resistant carbides such as MC, M2C or M6C. This can be achieved by increasing the amount of carbide forming elements such as Nb, V, Mo, W or Cr. Nevertheless it is important to maintain a certain amount of graphite in the microstructure to avoid sticking to the rolled material and to lower the sensitivity against mill incidents. It is well known that high amounts of carbide forming elements limit the graphite precipitation and therefore a sophisticated alloying concept is required for this material type. Not only the effects of matrix elements such as Si, Mn, Ni and Co but also the effects of Cr, Mo, W, Nb and V were studied in an intensive research project. This work gives an insight in the results of the project based on the example of the effects of Si and Cr on the phase amounts and the composition of the cementite phase.

The study presents the results of the effect of nanomodifying additives (WC, WO3, mixtures of W and Ti carbides) on the strength properties of concrete. These admixtures were obtained from the wastes of hard alloy metals. Microstructural and phase analysis of nanomodificators was performed. The positive effect of the proposed additives on the strength properties of concrete has been established.

Copper powder spraying is under study: the PMS-1 feedstock copper, the copper that is mechanically milled in a high-energy planetary mill, and the copper that is also spheroidized in a plasma jet. High-density copper coatings are obtained using a CCDS2000 detonation facility. The Vickers microhardness of coatings $$H_{{\mathrm V}_{0.1}}$$ , obtained from feedstock and mechanically milled copper powders, increases from 110 to 160 and from 150 to 185, respectively, and the microhardness of coatings from the spheroidized powder is $$H_{{\mathrm V}_{0.1}}=165$$ . An X-ray phase analysis is carried out, and the resulting data indicate that, during the spraying, the copper oxide is partially reduced.

Improvement of the physical and mechanical properties of hard alloys based on WC – Co widely used in manufacturing of structural and tool products nowadays results from the use of novel technologies providing formation of a homogeneous high-density structures. Slight deviations of the carbon content from the equilibrium state lead to the formation of brittle η-phases (in particular, Co3W3C) and, accordingly, to deterioration of the mechanical properties of the product. We present the results of studying the homogeneity of the phase composition of the samples of hard alloys WC + 10% Co, obtained using advanced technologies of plasma-chemical synthesis and spark plasma sintering (SPS). The layer-by-layer X-ray phase analysis revealed the heterogeneity of the phase composition in depth: the brittle η-phase (Co3W3C) appears at a depth of ≥100 μm and reaches a constant value of 18 ± 1 wt.% at >200 μm, which indirectly confirms the hypothesis of carbon diffusion from graphite punches contacting with the surface of sintered samples and makes it possible to expand the range of parameters affecting the process of spark plasma sintering.

The functional refractories used in the continuous casting process of steel are mostly made up of alumina (Al2O3) - carbon (C) system. Graphite is used as the main carbon source because of the properties it offered. Generally, these refractories contain about 30% residual carbon after coking. But the use of high carbon content leads to several disadvantages like carbon pickup by steel, high heat loss and generation of higher extent of COx gases, etc. Hence, the development of low carbon Al2O3-C refractories without conceding any beneficial properties is the challenge to the refractory technologists. Such a challenge is intended in current study with the use of nanocarbon as a complete alternative for graphite. The variation in physical, mechanical and thermo-mechanical properties with variation in amount of nanocarbon in the composition is studied. Phase analysis and microstructural developments are also evaluated along with the oxidation resistance at different temperatures. Because of its high reactivity, nanocarbon helps to form in-situ ceramic phases at much lower temperatures thereby enhances strength and other properties. But the increase in amount of nanocarbon above 2% found to deteriorate the properties.

Due to the unique combination of low density and their excellent properties-profile at elevated temperatures, intermetallic γ-titanium aluminide based alloys are a promising structural material for applications in aviation and the automotive industry. Additive manufacturing of a TiAl alloy of nominal composition Ti-48Al-2Cr-2Nb (in at. %), using electron beam melting, resulted in a banded and anisotropic microstructure. In this work, the present microstructure was examined by means of visible light and scanning electron microscopy with regard to morphology and phase distribution. Furthermore, a three-dimensional representation of the microstructure was generated based on differently oriented metallographic specimens. Phase analysis was performed using high-energy X-ray diffraction in order to quantitatively determine present phase fractions and to relate them to findings from microstructural analysis.

60 % Al2O3-based high alumina bricks are used in different areas of steel plants. In the Rourkela Steel plant, these bricks are used in the working lining of reheating furnaces and sinter plant furnaces. The primary requirement of the refractory is high thermal shock resistance in these areas. A laboratory investigation was carried out to study the influence of andalusite on the thermo-mechanical properties of 60 % Al2O3-based bricks. The effects of the amount of andalusite on the phase composition and microstructure of the refractory were investigated by XRD and FESEM. The results revealed that a higher percentage of andalusite provides better physical properties because of the higher mullite content in it. Phase analysis by XRD and microstructure analysis by FESEM proved the presence of mullite as major phase in the end product.

Failure analysis of a tubular oil heat exchanger made up of admiralty brass in an industrial unit was investigated. In the oil exchanger, circulating water is used as a coolant inside the brass tubes to reduce the temperature of oil flowing inside the brass shell. The causes of failure of the leaked admiral tubes were investigated performing various visual and microscopic examinations. Chemical analysis of the corrosion scales and its phase analysis with x-ray diffraction and microstructural examinations by optical and scanning electron microscopy were carried out. The study revealed that tube material was suffering from extensive de-zincification and under-deposit pitting.

The influence of structural transformations occurring during non-vacuum electron-beam surfacing of amorphous boron powder and the corrosion resistance of surface layers of chromium-nickel austenitic steel are investigated. It is shown that during surfacing a cladding with a dense arrangement of borides is formed. X-ray phase analysis showed that the modified layer almost completely consists of borides FexBy, CrxBy or complex borides (Cr, Fe)xBy located in the austenitic matrix. In this work, it was found that layers with the obtained structure provide an increase in the corrosion resistance of the surface of 12Kh18N9T steel by 1.5 times, while also providing high wear resistance.

Aluminum alloys based on the Al-Ge-Si system with a germanium content of up to 40 wt.%, promising for the brazing of aluminum alloy AA6082 with the stainless steel AISI 304, were studied. The temperature characteristics and microstructural and mechanical properties of the filler alloys were systematically investigated. Differential scanning calorimetry showed that with an increase in the germanium content from 28.0 to 40.0 wt.%, the liquidus temperature of the filler alloys decreased from 514.8 to 474.3 °C. X-ray diffraction analysis and electron microscopy data showed that the foil of the filler alloys reveals a homogeneous structure. The ingots of the alloys contain two eutectics, the first of which consists of a solid solution of (Al, Ge) with a solid solution of (Ge, Si), and the second consists of a solid solution of (Al, Ge) with a solid solution based on (Ge). When the content of germanium increases from 28.0 to 40.0 wt.%, a separation of the faceted solid solution particles (Ge, Si) and an increase in their number could be observed. Nanohardness measurements showed that the (Ge, Si) and (Ge) solid solutions had similar nanohardness, with values of 11.6 and 10.2 GPa, respectively. Simultaneously, the Al solid solution and the intermetallic Al7Ge2Fe phase exhibited significantly lower nanohardness values of 0.7 and 6.7 GPa, respectively. Brinell hardness measurements showed that the ingots of the filler alloys were sufficiently ductile and had a hardness comparable to that of AA6082, which is used for brazing with AISI 304 stainless steel. The obtained results for the studied ingots and the rapidly quenched foils can be used to predict the forming structure of the seam after brazing and adjusted for diffusion processes occurring between the brazed materials and the studied filler alloys.

In the present study, dissimilar friction welding between super alloy 718 and carbon steel friction welded to evaluate the formation of microstructure in the weld interface and in superalloy 718. The temperature during friction welding at weld interface was recorded to determine the temperature effect on the microstructural changes on alloy 718 side. The finite element modeling of weld interface temperature, deformation and stresses were evaluated and validated with the experimental results. The microstructural observation along with the weld interface and adjacent regions are studied. The effect of friction welding on superalloy weld interface and microstructural formation were investigated under electron backscattered diffraction analysis to evaluate the grain size measurements. The effect of thermomechanical action on the microstructure was evaluated by texture analysis.

Separation of aluminum from fine granules of black dross, which is a waste by-product in secondary aluminum production, was investigated. The separation was performed by a multi-stage electrostatic separation method. There are three stages to complete the separation, including preliminary separation, pulse charging enhancement and secondary concentration. Chemical and mineralogical compositions of collection products were analyzed and determined by X-ray diffraction (XRD) and X-ray Fluorescence (XRF). After multistage electrostatic separation, the Al2O3 content of the collection products increases from 50.74% to 69.77%. The mineralogical phase analysis indicates that the final recovery of metallic aluminum phase increases from 8% to 37%, and the aluminum oxide phase increases from 20% to 26%. The research results show the multi-stage electrostatic separation method is effective for recovering of aluminum from fine granules of black dross, and upgrades the black dross to a recoverable material.

Актуальность исследования обусловлена ограниченными запасами в нашей стране низкокремнистого алюмосодержащего сырья для производства металлургического глинозема по способу Байера. Поэтому руководство глиноземных комбинатов закупает данное сырье за рубежом (Гвинея, Бразилия, Ямайка). Стоимость транспортировки данного сырья с каждым годом становится все дороже и дороже, что повышает себестоимость металлургического глинозема. Также не стоит забывать о политических рисках, что еще больше усугубляет данную проблему. Следовательно, необходим переход на использование отечественного высококремнистого алюмосодержащего сырья, менее качественного, однако его запасы, находящиеся в непосредственной близости от глиноземных комбинатов, составляют сотни миллиардов тонн. Цель: исследование отечественной рудной базы высококремнистого алюминий содержащего сырья, определение первоочередных сырьевых источников и их месторождений, изучение характеристик сырья для оценки возможности его использования для производства металлургического глинозема. Объект: высококремнистые алюмосодержащие каолиновые глины сибирских месторождений. Проведенные исследования. Выполнен химический, фазовый, гранулометрический, микроструктурный, микрорентгеноспектральный и термогравиметрический анализы каолиновой глины Трошковского месторождения. Результаты. Анализ отечественной рудной базы позволил выявить наиболее крупные месторождения высококремнистого алюминиевого сырья, пригодного для получения металлургического глинозема. Установлено, что наиболее перспективным является Трошковское месторождение. Преимуществами данного месторождения являются огромные запасы высококремнистого алюмосодержащего сырья, высокая степень изученности месторождения и благоприятные инженерно-геологические условия. Проведенные исследования каолиновой глины Трошковского месторождения позволили сделать вывод, что глина данного месторождения может быть использована для получения металлургического глинозема по кислотно-щелочной технологии. The relevance of the research is caused by the limited reserves of low-silicon aluminum-containing raw materials for production of metallurgical alumina by the Bayer method in our country. Therefore, the management of alumina plants buys this raw materials abroad (Guinea, Brazil, Jamaica). The cost of transportation of this raw material every year becomes more and more expensive, which increases the cost of metallurgical alumina. Also, do not forget about political risks, which further aggravates this problem. Therefore, it is necessary to switch to the use of domestic high-silicon aluminum-containing raw materials of lower quality, but their reserves, located in close proximity to alumina plants, are hundreds of billions of tons. The aim of the research is to study the domestic ore base of high-silicon aluminum-containing raw materials, to define primary sources of raw materials and their deposits, to investigate the characteristics of raw materials to assess the possibility of their use for production of metallurgical alumina. Object: high-silicon aluminum-containing kaolin clay of Siberian deposits. Conducted research. Chemical, phase, granulometric, microstructural, micro-x-ray spectral and thermogravimetric analyses of kaolin clay of Troshkovsky Deposit were performed. Results. The analysis of the domestic ore base revealed the largest deposits of low-grade aluminum-containing raw materials suitable for production of metallurgical alumina. It is established that the most promising is the Troshkovsky Deposit. The advantages of this field are huge reserves of high-silicon aluminum-containing raw materials, a high degree of study of the field and favorable engineeringgeological conditions. The conducted research of the Troshkovsky kaolin clay deposits have led to conclusion that the clay of this fieldcan be used for production of metallurgical alumina by acid-alkaline technology.

In the present study, the microstructural and phase evolutions of [(Fe0.9Ni0.1)77Mo5P9C7.5B1.5]99.9Cu0.1 bulk metallic glass (BMG) were investigated during partial annealing process to improve its mechanical and magnetic properties. Phase analysis showed that some crystallites including FeNi2P, γ-Fe, α-Fe, and Fe3C were formed during various stages of annealing process. Formation of these nanocrystallites changed hardness of the investigated BMG during the annealing process. Furthermore, in order to investigate the effect of partial crystallization on mechanical behavior of the investigated BMG, the “indentation test” was used to determine the ductility changes. Moreover, the effect of partial annealing on the magnetic properties of this BMG was investigated.

In the steel industry, ferromanganese is an important additive. During the production of ferromanganese the ore goes through prereduction and reduction. The prereduction step is very important, as the degree of reduction during ferromanganese is important. Although many investigations have been conducted on different manganese ores, the current study investigated different phases that formed during prereduction when South African ore was used. The ore was mixed with carbon in excess as the reducing agent, and no fluxes were added while CO gas was blown in the furnace. The temperature was varied from 1000°C to 1200°C with 100°C interval. For each temperature, the time varied from 30 min to 90 min with 30 min interval. The ore to carbon ratio was 4:1. After the experiments, the resulting products were subjected to chemical and phase analysis using XRD, XRF and SEM.

The superalloys are usually used as structural material in jet engines due to their high-temperature stability and good endurance. Many components found in the hot-part of jet engines are of complex shape, therefore casting is utilized for to their production. One of the problems associated with the casting process of highly alloyed alloys, such as superalloys, is partitioning of alloying elements upon solidification. This segregation might lead to the formation of low melting temperature eutectics. Their presence in the material microstructure will have a negative effect on the weldability. Negative impact on weldability is one of the reasons why secondary phases should be avoided as microstructural elements in the welded materials. To eliminate such hazardous phases, the material should be subjected to a heat treatment with the aim of homogenizing the microstructure and chemical composition, which should enhance the weldability. The aim of this work was the application of analytical electron microscopy in combination with energy dispersive X-ray spectroscopy as well as tomographic techniques for qualitative and quantitative characterization of structural elements in as-cast Allvac 718Plus Ni-based superalloy subjected to later heat treatment. Alloy 718Plus is a newly developed superalloy in which the secondary Laves phase forms as a low-melting eutectic upon casting. The development of innovative materials for aeronautics and clean energy systems requires the use of modern research methods for structure characterization on the level from micro- to the nanoscale. The performed analysis, allowed identification of phases (Laves and η) occurring in interdendritic regions of as-cast Allvac 718Plus superalloy and analyzing their microstructure down to the atomic scale, which revealed their complex nature. The experiments and investigation show that advanced microscopic techniques and test methods in conjunction with tomographic techniques enable complementary information about solidified structures of the alloy to be obtained that can be useful for the understanding process of casting and welding of the Allvac 718Plus.

The processes occurring in glass-ceramic solders of sapphire-niobium seals, used as current lead-ins in gas-discharge lamps with a discharge in alkali-metal vapor, were studied. The structural changes occurring in the glass-ceramic solder, based on the system of oxides CaO–Al2O3 and CaO–MgO–Al2O3, upon heating to 1600°C with niobium diffusing into the melt, are analyzed on the basis of x-ray phase analysis of the composition and a study of the microhardness.

In this work, the effects of 1 wt%, 2 wt%, and 3 wt% CeO2 as an additive on the sintering behavior of alumina-rich spinel and magnesia-rich spinel powders subjected to sintering at temperatures of 1600 °C, 1650 °C, 1700 °C, and 1750 °C were investigated. The sintering behavior of the ceramics was investigated according to dilatometry measurements, linear shrinkage, bulk density, phase analysis, and microstructure. It was demonstrated that CeO2 hindered the sintering process in alumina-rich spinel by reacting with Al2O3 exsolved from the spinel to form platelet-shaped particles of CeAl11O18 interspersed between the spinel grains. Meanwhile, the presence of CeO2 promotes the sintering process in magnesia-rich spinel by being distributed in an isolated form among the spinel grains.

Crystalline cerium-zirconate (CZ) powders were synthesized via solution-assisted combustion synthesis route and calcined at 850°C for 8 h to obtain coarse crystalline powders. SEM (scanning electron microscopy) characterization studies were done to evaluate the morphology of the powders. XRD analysis of the resulting powder confirmed the presence of crystalline α-Ce2Zr2O7 along with a Ce2Zr2O8 phase having a disordered fluorite cubic lattice. Phase composition, lattice parameters, and the atomic positions were also investigated. Refinement of XRD data was done to quantify the amount of α-Ce2Zr2O7 and Ce2Zr2O8 phases. Ni-base superalloy Inconel 625 was chosen as the coating substrate, and the powders were coated using an air plasma spraying (APS). A thermally grown oxide (TGO)/Al2O3 layer was observed owing to the high temperature of the substrate as well as the diffusion of bond coat material into the substrate. Coated samples were characterized by SEM to study the surface morphology, coating thickness, and interface microstructures. The thickness of the coated sample was found to be 400 μm. Thermal cycling test of the coated sample was carried out at 750°C for 50 h to evaluate the thermal shock resistance of the coating as well as the spalling behavior of the coating. Preliminary oxidation tests were carried out for 50 h at 750°C to evaluate the oxide growth by measuring weight gain of the oxide layers formed. Oxide growth signifies the gradual increment of layers over a period with a parabolic rate constant of about Kp= 1.18 × 10–3 mg2 cm–4 h–1.

The article focuses on the impact of waste marble powder on resulting cement composites. We investigate of influence waste marble powder on the hydration process and hence the resulting phase composition. The hydration process was investigated using calorimetry and phase composition of the resulting composite by electron microscopy. The results are compared with a reference sample composed of Portland cement.

This paper clarified the microstructural element distribution and electrical conductivity changes of kaolin, fly ash, and slag geopolymer at 900 °C. The surface microstructure analysis showed the development in surface densification within the geopolymer when in contact with sintering temperature. It was found that the electrical conductivity was majorly influenced by the existence of the crystalline phase within the geopolymer sample. The highest electrical conductivity (8.3 × 10−4 Ωm−1) was delivered by slag geopolymer due to the crystalline mineral of gehlenite (3Ca2Al2SiO7). Using synchrotron radiation X-ray fluorescence, the high concentration Ca boundaries revealed the appearance of gehlenite crystallisation, which was believed to contribute to development of denser microstructure and electrical conductivity.

The object of research is the hydration of binders obtained from scrap concrete of destroyed buildings and structures. We used fractions of scrap concrete 0.00–0.16 mm and 0.16–0.315 mm, as x-ray phase analysis of various fractions of scrap concrete showed that these fractions have the highest content of non-hydrated alite and belite particles.

The article describes the studies’ results of steels with applied boron-based hardsurfacing overlays. The overlay was done in four different ways. The materials obtained differed in chemical composition, properties and wear resistance. A detailed technical process of surfacing and the surfacing charge composition, which makes it possible to obtain the necessary material, is given. Studies of hardness, macro- and microstructure, chemical and X-ray phase composition of the obtained materials have been carried out. The descriptions of the overlays’ characteristic phases are made and their properties are given. The chemical composition of the obtained overlays has been determined by the emission spectroscopy method. The X-ray phase analysis of the samples has also been carried out and the percentage of the additional modifier introduced into the overlays has been determined. Based on the results of the studies carried out, the conclusions about the optimal method of metal hardening have been drawn.

The reason and mechanism of the failure of SA210-C steel liquid wall were analyzed by means of macro morphology analysis, chemical composition analysis, microstructure analysis and XRD phase analysis. The test results show that the main reason for the failure of SA210-C steel water wall tube is the corrosion under the inner wall scale, and the long-term unqualified boiler water quality is the main factor causing the corrosion of water wall.

Composites including silicide of tungsten and boride of tungsten intermetallic compound as reinforced agents in alumina matrix have a good mechanical properties in low and high temperature (high friction resistance, strength, resin stance to creep and relatively high thermal shock resistance), moreover, they have chemical neutral with a high corrosion resistance in a high corrosive and high temperature environment. The purpose of this study is to investigate thermal analysis, phase and microstructural evaluation during synthesis of above mentioned composite by combustion aluminothermic processing in three systems 1-Al+Si+WO3, 2-Al+B2O3+WO3 and 3-Al+B2O3+Si+WO3. A Ball-milled starting material according to stoichiometric ratio was thermal analyzed (DTA-TGA) for each of above mentioned system. The XRD results never show any new phase during ball-milling even up to 10 hours. The forming of tungsten silicide (WxSiy) is in lower temperature in comparison with tungsten boride (WxBy) during the thermal analysis experiments. The presence of Si in the Al+B2O3+WO3 system facilitates the formation of tungsten borides. The microstructural observations show a uniform and dense distribution of silicide and boride of tungsten in the alumina matrix. Silicide phases are small grain with spherical morphology whereas; the boride phases are coarser and relatively elongated with irregular morphology.

The results of testing method of synthesis of a high-entropy AlNbTiVZr alloy using metallothermic reduction of group IV and V metals from their oxides are presented. At the first stage, joint aluminothermic reduction of metals was performed in a resistance furnace. Then, to achieve uniformity and remove harmful impurities, the metal was remelted in a vacuum furnace with an inert atmosphere. The alloy obtained after the second remelting was subjected to chemical and x-ray phase analysis. The results of the analysis revealed the presence of a solid solution of Zr (Nb, V) with TiAl inclusions, confirming the prospect of using metallothermic synthesis to produce a high-entropy alloy with a single-phase structure.

The paper presents research results on the analysis of ceramic brick manufactured with the addition blast-furnace sludge which is a waste of AO ‘EVRAZ’ metallurgical combine. The effect of the silica nanopowder is considered in relation to physical and mechanical properties of finished materials. It is found that the nanopowder addition in the amount of 0.05 wt .% leads to the compressive strength increase. The X-ray phase analysis show that the nanopowder addition increases the amount of quartz-containing components which represent mostly mullite- and anorthite-like compounds.

The study has revealed the regularities of the effect produced by increasing the content of scale of steel 12Cr18Ni10Ti in the charge from 5 to 75 mass % on the contents of the products of carbon thermal reduction of oxide waste of corrosion-resistant steels. The concentration of Ni is increased from 0.8 to 7.0 mass % when the Cr content ranges from 15.9 to 17.1 mass %. The concentration of Cr in the extraction products within the range of 16.1–17.1 mass% is provided with the content of scale of 95Cr18 steel in the charge in the range from 5 to 55 mass %. It has been found that metallization products mainly consist of a solid solution of alloying elements in α-Fe. Fe 3 O 4 , Fe 3 C, and Fe 2 C were also identified. The microstructure of the extraction products is spongy and disordered. The particles are sintered, with varying Cr and Ni contents in the ranges of 7.47 to 18.03 mass % and 2.97–10.40 mass %, respectively. The study has helped achieve environmentally safe conditions for solid-phase extraction of chrome and nickel containing industrial wastes from the production of corrosion-resistant steels with the return of the alloyed product to the welding industry

This study aims to investigate the role of graphene on wear and corrosion behaviors of pure magnesium. Magnesium/Graphene Nanoparticle (GNP) composites were fabricated via semi powder metallurgy method with a different content of graphene (0.1, 0.25 and 0.5 wt%). The effect of graphene in pure magnesium was examined by hardness, wear and corrosion tests. Microstructural and phase analysis were carried out by Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) analysis. Experimental results revealed that, hardness values increased with the addition of graphene. There was a same trend in wear behaviors with increase of graphene rate. The best wear performance was belonging to the 0.50 wt% graphene/mg composite under load of 10N. So improvement of wear properties was achieved using graphene as reinforcement. According to the microstructural evolution, the uniform distribution was achieved for all samples but partially agglomeration could be seen in Mg-0.50 wt% graphene. Compared to the pure magnesium, corrosion performance was affected negatively in graphene reinforced composites.

High-strength steel is widely used in hot forging products for application to the oil and gas industry because it has good mechanical properties under severe environment. In order to apply to the extreme environment industry requiring high temperature and high pressure, heat treatments such as austenitizing, quenching and tempering are required. The microstructure of high-strength steel after heat treatment has various microstructures such as Granular Bainite (GB), Acicular Ferrite (AF), Bainitic Ferrite (BF), and Martensite (M) depending on the heat treatment conditions and cooling rate. Especially in large forged products, the difference in microstructure occurs due to the difference in the forging ratio depending on the location and the temperature gradient according to the thickness during post-heat treatment. Therefore, this study attempted to quantitatively analyze various phases of F70 high-strength steel according to the austenitizing temperature and hot forging ratio using the existing EBSD analysis method. In addition, the correlation between microstructure and mechanical properties was investigated through various phase analysis and fracture behavior of high-strength steel. We found that various microstructures of strength steel depend on the austenitizing temperature and hot forging ratio, and influence the mechanical properties and fracture behavior.

Phase transformation and magnetic properties of limonite ore with 40.10% Fe via microwave roasting with addition of alkali lignin were investigated by chemical phase analysis and vibrating sample magnetometer (VSM) analysis, respectively. The results of chemical phase analysis indicated that phase compositions and contents of iron in microwave roasted limonite ore were varied with the dosage of alkali lignin, the roasting temperature, the roasting time and the microwave power, and among them the dosage of alkali lignin exerted more significant influence. Iron oxides in limonite ore could be reduced to magnetic iron oxides including γ-Fe2O3 and Fe3O4 in the following sequence during microwave roasting process by evenly distribution of alkali lignin below 5%: FeOOH/α-Fe2O3→γ-Fe2O3→Fe3O4, accompanied with small amount of FeO, and as the dosage was over 5%, γ-Fe2O3 and Fe3O4 could be in turn successively transformed into α-Fe2O3. Magnetic property studies demonstrated that an iron concentrate containing 88.72% magnetic iron oxides with a maximum saturation magnetization of 41.393 emu/g could be produced from roasted ore which was obtained by microwave roasting at 200 °C and 600 W with 5% alkali lignin for 30 min. In addition, the roasted ore was further used for magnetic separation, and the results showed that combining microwave roasting with addition of 5% alkali lignin could improve the iron recovery from the roasted ore distinctively. It was concluded that the microwave roasting process in the presence of alkali lignin could be a promising approach to effective utilization of limonite ore resources.

The majority of primary pyrometallurgical copper making processes involve the formation of two immiscible liquid phases, i.e., matte product and the slag phase. There are significant gaps and discrepancies in the phase equilibria data of the slag and the matte systems due to issues and difficulties in performing the experiments and phase analysis. The present study aims to develop an improved experimental methodology for accurate characterisation of gas/slag/matte/tridymite equilibria in the Cu-Fe-O-S-Si system under controlled atmospheres. The experiments involve high-temperature equilibration of synthetic mixtures on silica substrates in CO/CO2/SO2/Ar atmospheres, rapid quenching of samples into water, and direct composition measurement of the equilibrium phases using Electron Probe X-ray Microanalysis (EPMA). A four-point-test procedure was applied to ensure the achievement of equilibrium, which included the following: (i) investigation of equilibration as a function of time, (ii) assessment of phase homogeneity, (iii) confirmation of equilibrium by approaching from different starting conditions, and (iv) systematic analysis of the reactions specific to the system. An iterative improved experimental methodology was developed using this four-point-test approach to characterize the complex multi-component, multi-phase equilibria with high accuracy and precision. The present study is a part of a broader overall research program on the characterisation of the multi-component (Cu-Fe-O-S-Si-Al-Ca-Mg), multi-phase (gas/slag/matte/metal/solids) systems with minor elements (Pb, Zn, As, Bi, Sn, Sb, Ag, and Au).

The segregation of the elements during solidification and the direct formation of destructive phases such as Laves from the liquid, result in in-homogeneity of the cast structure and degradation of mechanical properties. Homogenization heat treatment is one of the ways to eliminate destructive Laves from the cast structure of superalloys such as 718Plus. The collected data presents the effect of homogenization treatment conditions on the cast structure, hardness, and tensile properties of the alloy 718Plus in the presence of boron and zirconium additives. For this purpose, five alloys with different contents of boron and zirconium were cast by VIM/VAR process and then were homogenized at various conditions. The microstructural investigation by OM and SEM and phase analysis by XRD were done and then hardness and tensile tests were performed on the homogenized alloys. Keywords: Homogenization, Boron, Zirconium, 718Plus, Strength, Ductility

This paper investigates fatigue behavior of precipitation hardenable 17-4 PH stainless steel after simultaneous aging and plasma nitriding. For this purpose, “solution treated”, “aged” and “simultaneous aged and nitrided” specimens were compared in terms of hardness, phase analysis, residual stress and fatigue strength. Hardness values of aged specimens were recorded during aging process to find the optimum condition in terms of time and temperature for plasma nitriding at which specimens can be simultaneously nitrided and aged. Plasma nitrided specimens were analyzed for residual stresses, and its effect on mechanical properties including hardness and fatigue strength. The specimens that were plasma nitrided at lower temperatures had the highest core hardness. Increasing the nitriding temperature/time caused an increase in residual stress and, consequently, a higher surface hardness. Both nitriding and aging processes improved fatigue life by more than 40%. Plasma nitriding imparts beneficial effect mainly during high stress fatigue while aging treatment is more effective on low stress fatigue properties. Specimens nitrided at 500 °C for 5 h experienced longer fatigue life for high stress conditions while specimen aged/nitrided at 400 °C for 10 h exhibited the highest fatigue strength.

In Poland, researchers have a very strong interest in archaeometallurgy, which, as presented in classical works, focuses on dating artefacts from the prehistoric and early medieval periods in the form of cast iron and copper castings. This study, extending the current knowledge, presents the results of a microstructure investigation into the findings from the Modern era dating back to the late Middle Ages. The investigated material was an object in the form of a heavy solid copper block weighing several kilograms that was excavated by a team of Polish archaeologists working under the direction of Ms Iwona Młodkowska-Przepiórowska during works on the marketplace in the city of Czestochowa during the summer of 2009. Pre-dating of the material indicates the period of the seventeenth century AD. The solid copper block was delivered in the form of a part shaped like a bell, named later in this work as a “kettlebell”. To determine the microstructure, the structural components, chemical composition, and homogeneity, as well as additives and impurities, investigations were carried out using light microscopy, scanning electron microscopy including analysis of the chemical composition performed in micro-areas, and qualitative X-ray phase analysis in order to investigate the phase composition. Interpretation of the analytical results of the material’s microstructure will also help modify and/or develop new methodological assumptions to investigate further archaeometallurgical exhibits, throwing new light on and expanding the area of knowledge of the use and processing of seventeenth-century metallic materials.

The chemical composition of pellets of various basicity from pig iron ore materials is described. The metallurgical characteristics (reducibility, strength, softening and melting temperatures) is analyzed. The micro X-ray diffraction phase analysis is made. Also the sinter of various basicity from titaniferous raw materials is investigated.

Several samples of dusts from steel and coke plants (collected mostly with electro filters) were subjected to the investigation of content of mineral phases in their particles. Additionally, sample of bog iron ore and metallurgical slurry was studied. Next, the magnetic susceptibility of all the samples was determined, and investigations of iron-containing phases were performed using transmission Mössbauer spectrometry. The values of mass-specific magnetic susceptibility χ varied in a wide range: from 59 to above 7000 × 10−8 m-3·kg−1. The low values are determined for bog iron ore, metallurgical slurry, and coke dusts. The extremely high χ was obtained for metallurgical dusts. The Mössbauer spectra and X-ray diffraction patterns point to the presence of the following phases containing iron: hematite and oxidized magnetite (in coke and metallurgical dusts as well as metallurgical slurry), traces of magnetite fine grains fraction (in metallurgical dusts), amorphous glassy silicates with paramagnetic Fe3+ and Fe2+ ions, traces of pyrrhotite (in coke dusts), α-Fe and nonstoichiometric wüstite (in metallurgical slurry), as well as ferrihydrite nanoparticles (in bog iron ore). For individual samples of metallurgical dusts, the relative contributions of Fe2+/3+ ions in octahedral B sites and Fe2+ ions in tetrahedral A sites in magnetite spinel structure differs considerably.

The basic type of carbide for making high-carbon wear-resistant structural steel without using a thermochemical treatment was defined. With consideration of the phase composition of the matrix after tempering, the preliminary intervals of alloying of high-carbon structural steel for gearwheels were recommended.