Seznam abstraktů 2017: POSTEROVÁ SEKCE E

Lithium-air (Li-O2) batteries have received significant attention in the past several years due to their theoretical energy density which is comparable to that of fossil fuels. However, Li-O2 battery performances have not reached the desired values yet, due to the problems arising from the anode/cathode electrode kinetics and the limited efficiencies of the electrochemical reactions. In this work, we synthesized both the anode and cathode to obtaine the improved and stable electrode kinetics. Li – Si based alloy anodes were synthesized by mechanical alloying under the protective atmosphere. These alloys were observed as strong canditates to Li metal anodes due to their more stable characteristics during the both charging and discharging. The graphene based cathodes were synthesized by optimizing the porosity depending on the relationship between specific surface area/pore size and capacity values in Li-O2 cell. Porous graphane based cathodes with a specific surface area varies from 200 to 400 m2g-1 were synthesized with the template method by using graphene oxide solution and silica nanoparticles (as a template: 50 - 200nm), followed by the heat treatment. LiTFSI:DME electrolytes in various compositions were used in the Li-O2 cell. The cyclic voltammetry (CV) experiments with in situ electrochemical quartz crystal microbalance (EQCM) measurements were applied to identify the influence of the pore size gravimetrically in the same electrolyte.

The paper presents the results of physical modelling of 7075 aluminium alloys in T6 state deformation. The tests were performed using STD 812 torsion plastometer. The influence of different deformation schema on the level of stress, selected properties and changes in structure of the alloy was determined. Preliminary experimental studies of the rolling process in a three high skew rolling mill for the selected variant were also performed.

This paper presents results concerning copper-zeolite composites fabricated by powder metallurgy. It focuses on the effect of zeolite particles on the properties of the sintered material as well as the quality of the bonding between the zeolite reinforcement and the copper matrix. Before the sintering process, the zeolite morphology and composition were characterised. The zeolite powder (0.0-0.2 mm fraction) used in the experiments was ground tuff rock extracted from the Kucin Quarry (VSK PRO-ZEO s.r.o.) in Slovakia. The as-delivered material was imaged and analysed using the SEM/EDS and XRD techniques. Before sintering, the powder mixtures were compacted on one side with a hydraulic press at a pressure of 400 MPa. The sintering process was carried out in a laboratory tube furnace at 950 °C under an atmosphere of dissociated ammonia. The sintering time was fixed at 60 minutes. The resulting agglomerates were measured for density, hardness, porosity. SEM/EDS analysis was employed to observe the microstructure and composition of the metallographic sections. The addition of zeolite powder to the copper matrix (5, 10 or 20% by weight) increased the porosity and hardness of the sintered material but decreased its density.

In this work, plasma coatings of NiAl10 and NiAl40 on magnesium alloy AZ91 substrate were prepared by the hybrid plasma spraying system WSP®-H 500. The both plasma sprayed coatings of NiAl10 and NiAl40 have metallurgical bond. The thicknesses of microstructures in the cross-section of NiAl10 and NiAl40 plasma sprayed coatings prepared by 9 passes were 374 and 440 m respectively. Adhesion test of plasma sprayed layers was performed using a modified ASTM C 633 standard. The tensile adhesion strength values are 24.7 MPa for NiAl10 coatings and 12.3 MPa for NiAl40 coatings. Abrasion resistance according to Slurry Abrasion Response (SAR) test of NiAl40 layers had similar values (0.12 g/cm2) in a comparison with the uncoated AZ91 (0.126 g/cm2). Layers NiAl10 had greater weight losses (0.1751g/cm2) than uncoated AZ91. Microhardness of plasma coating of NiAl40 is several times greater than microhardnesses of plasma coating of NiAl10 and uncoated substrate AZ91.

The AZ91/AlSi17 bimetallic samples were formed by using a compound casting method. The AZ91 magnesium alloy was top-poured onto the AlSi17 aluminium alloy insert placed in the steel mould. Two kinds of AlSi17 inserts, differ in the microstructure, were used in this process. The insert cut from AlSi17 alloy ingot is characterized by microstructure containing irregularly shaped and unevenly distributed, large primary Si particles. To refine the primary Si particles, the AlSi17 alloy was cast into cold steel mould. The insert cut from rapidly solidified AlSi17 alloy showed fine primary Si particles homogenously distributed in the matrix. It was shown, that microstructure of the AZ91/AlSi17 bonding zone was dependent on the microstructure of insert used in this process. Applying of the insert containing course primary Si crystals, led to formation of the bonding zone, composed of intermetallic phases and not fully reacted Si particles. The Si particles are too large to be consumed in reaction with Mg during compound casting and fully transformed to Mg2Si. Use of the insert with refined microstructure allows to obtain the bonding zone with fully reacted Si crystals. I this case, the eutectic (Mg¬17Al12 + a solid solution of Al in Mg) was observed on the AZ91 side in bonding zone. The bonding zone close to AlSi17 alloy was composed of Mg2Si particles uniformly distributed in Al-Mg intermetallic phase matrix.

Magnesium and calcium phosphates composites are promising biomaterials to create biodegradable load-bearing implants for bone regeneration. The present investigation is focused on the design of an interpenetrated magnesium – tricalcium phosphate (Mg-TCP) composite. In the study, TCP scaffolds were 3D-printed with a tip of 250 µm in aperture. Final scaffolds with parallel grids and internal macro-pores of 150, 350, 500 and 1000 µm were obtained and sintered at 1100 °C for 5h. Later, the infiltration with commercial pure Mg using a new technique named Current Assisted Metal Infiltration (CAMI) was performed. CAMI is a novel technique that allows molten metal infiltration even into brittle ceramic preforms in less than 15 minutes. Fast melting and final solidification of the Mg-TCP composite is achieved with the assistance of a pulsed electrical current as heating resource. The effects of pore size on infiltration were analyzed by X-ray computer microtomography (μCT). Virtual tomographic reconstructions were used to observe the components distribution and the remaining porosity of the composite after the infiltration. Results show a good penetration of the metal into the TCP scaffolds. Nevertheless, fracture of some TCP structures after the infiltration was observed, mainly in those scaffolds with pores of 150 µm. Some porosity after infiltration was observed, however, it does not exceed 5% of the total volume of the specimen. Pores were located outside or in the periphery of the preform and were produced during the solidification of magnesium.

The microstructural stability of fully lamellar Ti-45Al-5Nb-0.2B-0.75C alloy was studied under thermal exposure at 750, 850 and 950 °C for 3400 h. The microstructure analysis by scanning electron microscopy show that the most dominant change in the microstructure during the thermal exposure was that the α2 lamellae thinned gradually, and thinning was more pronounced with increasing temperature and with increasing time. Formation of recrystallized γ grains and Ti2AlC carbides were also observed especially during the temperature 850 and 950 °C after prolonged heat treatment. The effect of microstructural changes during the thermal exposure on mechanical properties was evaluated and discussed.

Hydrogen absorption in chosen binary Mg-X (X-Al, Ga, In, Si and Sn) intermetallics was studied. These compounds are prospective as additives in other Mg-based hydrogen storage materials. From this point of view, it is desirable to know the hydrogen solubility in Mg-X and their resistivity against hydride formation. The present study was carried out at temperatures up to 623 K.

In the present work, we explore the phenomenon of jumping of metal microparticles during fast heating ramps performed with the help of an ultrafast scanning calorimeter (UFSC). We observed that the pure metal particles of a few nanograms, which are typically used for the temperature and power calibration of UFSC, frequently exhibit jumps in the melting region. Importantly, the jumps always happen at the beginning of the melting transition. In the case of jumps, the UFSC heating curves reveal only a small fraction of the total latent heat of the particle, typically on the order of 20%. The rest of the heat is not detected because the contact of the particle with the heating element is lost after the particle take off. The jumping behavior was further analyzed by combining in-situ fast CCD observations and UFSC. These experiments allowed to quantify the duration of the jumps and establish correlations between the frequency of jumps and such parameter as the sample thermal history. The work can help to evaluate in an unconventional way the mechanical stresses stored in the metal lattice during the crystallization process and maybe pave the way to fabrication of mechanical actuators using the effect of the stress release during melting.

Inconel® is a group of nickel-based superalloys, which are featured by superior combination properties. Their good mechanical properties at high temperature, good oxidation and corrosion resistance cause them to become attractive choices for diverse applications in aerospace, marine, chemical, petrochemical and energy industries. Welding of Ni-based superalloys is diffucult, because alloying elements such as Nb, Cr, Ti cause harmful precipitations of carbides. Another concern is segretation of Nb and formation of Nb-rich brittle intermetalic Laves phase in the interdendritic regions during weld metal solidifications. In some applications, especially in the aerospace, implementation of innovative design and technology for property, quality and performance are necessary. A favorable solution seems to be multi-material joining. However, problems associated with the proper selection of materials and welding method are given rise to. Therefore, any research on the microstructure and properties are justified. In this study, laser beam weldability of these superalloys was evaluated, and the microstrutural characteristic and the mechanical properties of their weld joint were investigated. Optical microscopy, scanning electron microscopy and hardness test were utilized for the investigation.

The article presents the research results on acoustic emission (AE) generated by process of friction stir welding of sheets made of AW-5083 aluminium alloy. Nowadays acoustic emission method is used in many fields of science, including in the diagnosis of machining and joining processes such as turning, grinding, milling, welding, etc.
Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminium alloy sheets. FSW method can be an alternative to traditional arc welding methods i.e. MIG or TIG. The joining process was carried out on laboratory stand built on the basis of universal milling machine FWA-31. Joining parameters chosen after optimization of the FSW process were presented.
The research was carried out on a laboratory test stand using an acoustic emission set made by Vallen System. This set included: 4 channel signal recorder AMSY 6, two measurement modules ASIP-2/S, preamplifier with a frequency range 20 kHz - 1 MHz and the strengthening of 34dB and AE signal measurement sensor type VS 150M, with a frequency range 100 - 450kHz. During the study, the acoustic emission (AE) generated by rotating tool and friction between joining materials and tool surface was recorded. The following parameters were determined: amplitude, number of events - hits, the effective value of the signal (RMS).
The study can be the basis for the use of acoustic emission method to monitor the process and determine the parameters of the friction stir welding for obtaining a high quality joint.

The paper presents the results of the outer surface quality examinations of Zr-1%Nb alloy tubes after the process of pilger rolling with a deformation of ε=72% on a KPW rolling mill. For the analysis of the effect of the strain rate and the degree of deformation of the magnitude of the yield stress σp of the investigated alloy, an experiment was programmed based on the industrial conditions and physical modelling of the rolling process was carried out. For the physical modelling of the process under examination, the GLEEBLE 3800 metallurgical process simulator was employed. Based on the examination results, the relationship σp= σp(ɛ, έ) has been obtained for discontinuous cold deformation conditions and recommendations for the division of the strain distribution over the deformation zone length have been given.

Super-elastic NiTi alloys which are shape memory were discovered in the 1960s. Their biocompatibility lead to their large development in orthodonty implying highly pure material using. Pyrometallurgical recycling of these alloys require high temperature treatment at least 1350°C (eutectoid) under controlled atmosphere. Less restraining process is to leach alloy by hydrometallurgy within sulfuric acid. However only 63 % of materials can be separate at 200°C under atmosphere, while whole separation was reached by hydrothermal way. The optimization of these method showed that in closed recipe at 200°C separation of NiTi alloys is possible with a reasonable cost. The recovered nickel sulfate or titanium sulfate solutions, as well as TiO2 precipitate have a potential commercial value. Adjusted heat post-treatment and/or pH control of solutions can result to ready-consumable nickel galvanization solution, TiO2 allotropes particle like anatase (photocatalyst) or rutile.

Al-Si alloys, the most important group of aluminium-based metals, are typical casting metals. Nevertheless, 3D printing technology also enables to process these alloys. It brings along advantages of processing simplicity consisting in a single-step route and very complex geometry avoiding use of complicated and expensive cooling systems of casting molds. When applying 3D printing, a unique microstructure evolution occurs. This conference contribution deals with characterization of AlSi10Mg in terms of characteristic microstructure formed by layer-wise melting process followed by rapid cooling and mechanical properties exceeding those of casted counterparts. Domains representing solidified meltpools are delimited by heat affected zones. Columnar grains grow across these domains in the building direction and are formed by a very fine cellular dendritic substructure of average size of 0.4 µm. Alpha-Al dendrites are bordered by interdendritic Si phase. Such a fine structure results in very high mechanical strength (255±13 MPa in tension, 721±27 MPa in compression), even without precipitation hardening treatment. ACKNOWLEDGEMENTS: Authors wish to thank the Czech Science Foundation (project no. P108/12/G043) and specific university research (MSMT no. 20-SVV/2017) for the financial support of this research.

Electric traction is a complex energy supply system for electric locomotives. One of the most important components of this system, to ensure continuous current flow, is a pantograph contact strip. It is a part of pantograph located on top of traction vehicles which allows them to move within the electric traction through constant sliding contact with contact wires. This paper presents method of fabrication and selected properties of metallic-carbon composite materials dedicated for sliding strips used in railway systems. Porous carbon materials prepared for metal infiltration were produced by mixing of carbon powders with a binder, extrusion of the resultant slurry through a suitably profiled die, thermal debinding and sintering. Developed carbon materials are characterised by open porosity in the range of 4-15% calculated by the difference in weight for the same volume of tested samples. Obtained carbon materials were next impregnated by molten zinc and tin with the use of gas-pressure infiltration process. The results showed that mechanical properties and electrical resistivity of obtained materials were enhanced as a result of metal impregnation. Additionally microstructural characterization of the composites showed structure of the interpenetrating network of phases, the absence of unfilled pores and good cohesion at the carbon – metal interface.

Critical raw materials, such as rare earths (REEs), have a high economic importance for the EU, combined with a high risk associated with their supply depending on very limited sources. Therefore, the recovery of the RE elements is extremely important for both economic and environmental reasons. NiMH batteries contain nickel, cobalt, lanthanum and other REEs and can be used as a secondary source of those metals. One of possible methods of their recovery is a hydrometalurgicall process consisting of following steps: leaching of batteries, separation of metal ions from leach pregnant solution (LPS) and obtaining of final products (metals or their compounds). The presented paper deals with leaching of spent NiMH batteries in aqueous solutions of chosen organic acids (like acetic, lactic or tartaric). As a result solutions containing nickel(II), cobalt(II), lanthanum(III), neodymium(III) and cerium(III) ions with concentration up to 2.5, 0.4, 0.5, 0.3 and 0.2 g/dm3, respectively, were obtained.

An increase in the consumption of platinum in the automotive industry is related to the growing number of cars manufactured. Modern and well-used equipment of this type which is fitted as standard in cars should work for at least 8·107 - 9·107 metres. When worn, they are considered as waste being a valuable source of platinum-group metals (platinum, palladium and rhodium) which act as catalysts in catalytic converters. The management of spent catalytic converters helps to reduce the amount of waste disposed as well as to lower the emission of pollution to the air in relation to the processes involving obtaining such metals in the production technologies from raw materials. Various hydrometallurgical, pyrometallurgical or mixed methods are used for the recovery of noble metals from spent catalytic converters. The purpose of the article is to present an experimental method for the recovery of noble metals from spent catalytic converters. This method involves flushing of spent catalytic converters with a liquid collector metal with the use of a magneto-hydro-dynamic pump for the intensification of the process and is applied to recover platinum from catalytic converters by melting them (collecting) in the liquid metal. In the paper the optimization of the operation of the system for the recovery of platinum-group metals which is essential in the light of later commercialization of the solution is proposed.

The Inconel nickel-chromium superalloy 625 has outstanding corrosion resistance and very high strength based on matrix hardening of the alloying elements and the different intermetallic phases and carbides formed in the matrix and along the grain boundaries. During the hot rolling, dynamic recovery and dynamic recrystallization occur and refine the crystal grain size and reduce the hot-deformation resistance. The control of the microstructure is of great interest for optimising the final mechanical properties. We found that during the hot rolling the recrystallization starts on the grain boundaries, followed by the twin grain boundaries and, at even higher stresses, the recrystallization occurs on the (TiNb)CN phases inside the crystal grains. We observed that the fraction of recrystallized grains increases after the second pass, and sharply decreases afterwards. The sub-structured grains show a peak after five passes, whereas the most deformed grains are observed after three passes. After the first pass, we can observe a sharp peak in the number of grain boundaries with a misorientation angle of 60 degrees. Low-angle grain boundaries begin to show a significant presence after the third pass and are relatively prominent after the fifth pass, while the 60-degree-angle boundary fractions decrease with the number of passes. With an increasing number of passes we can observe that the number of smaller grains increases. There are also some textures of the newly recrystallized grains, which are related to the textures of the primary grains, but also to the number of hot-rolling passes.

Solid state mixing, such as mechanical alloying (MA), represents an ecological and technologically reasonable economical processing method how to achieve homogenous distribution of hard particles in composite microstructure. The advantage of working at ambient temperatures, without a process control agent (PCA), opens new route for the preparation of advanced materials. The use of mechanical alloying includes several advantages, namely control of the particle size. The aim of the current work is to prepare TiB2 phase dispersion in aluminium matrix using mechano-chemical processing. For this purpose a mixture of aluminium, boron trioxide and titanium powders were subjected to high energy ball milling. The microstructural and phase evaluation of powders particles after different milling times and after addition of aluminium (two-step mechanical alloying) was conducted by using scanning electron microscopy (SEM), X-Ray diffractometry (XRD) and scanning differential calorimetry (DSC). The results indicate that two-step milling method led to the production of aluminium matrix composite with a small amount of fine TiB2 particles distribution.

In this work, the effect of processing conditions on microstructure and mechanical properties of Fe–Al–Si alloys is studied. The microstructure and mechanical properties during each step of processing consisting of mechanical alloying and spark plasma sintering are characterized by means of light microscopy, scanning electron microscopy, x-ray diffraction and micro/nano hardness measurements. Effect of sintering temperature (including heating rate), time and pressure on chemical/phase composition, microstructure and overall mechanical properties is presented and discussed.

This article describes an effect of lithium content in AZ31 magnesium alloy on the grain refinement of the structure processed by severe plastic deformation method ECAP (Equal Channel Angular Pressing). Was realized research of ECAP technology influence on the flow stress, hardness, and structure of the hot extruded magnesium alloys AZ31, AZ31+7,5%Li and AZ31+15%Li ECAPed at temperature 523 K (250°C). Were measured flow stresses during ECAP process and hardness evaluation after individual passes. The microstructure was analyzed on an optical and electron microscope by using SEM and EBSD.

Tungsten is often considered as one of the candidate materials for inner chamber lining in the research fusion reactor ITER. ODS steel materials present a viable materials choice for high temperature applications such as the support structure for the tungsten lining. Joining of these two very different materials is a problem that, among other, may be approached by the route of electron beam welding technology. The presented paper shows experimental work done on joining an tungsten alloy and the MA 956 ODS steel by means of electron beam weld. Individual samples are distinguished by using different filler material, preheating temperature or welding parameters. The samples were analyzed in as-welded state to evaluate microstructures in the weld material also in terms of mixing of the alloys components by means of scanning electron microscopy. Mechanical properties were evaluated using measurements of microhardness across the weld metal. The results show that although it is possible to create weld between tungsten and steel material, the joint material shows better homogeneity and lower defects occurence when some filler material is used.

The cubic Laves phases RCo2 compounds (R = rare-earth metal) are characterized by intrinsic instability of the Co-sublattice magnetic moments. In such compounds in the region of the Curie temperature, both significant magnetostriction and a large magnetocaloric effect (MCE) are observed. Using various combinations of rare-earth metals and the partial substitution of a metal for Co, one may improve their properties and engineer new functional materials based on them. The present study is focused on analyzing of magnetic and structural features Tb-Dy-Ho-Co-T (T = Al, Fe) multicomponent alloys.
The alloys of Tb0.3Dy0.35Ho0.35Co1.75T0.25 were synthesized in helium atmosphere in electric arc furnace with followed homogenizing annealing. The purity of Co and rare-earth metals was 99.99 and 99.9%, respectively. X-ray diffraction analysis shows that all compounds under study had single phase MgCu2-type structure. The temperature dependence of lattice parameters was investigated. The surface topology of the synthesized RCo2 Laves-phase samples was studied by atomic force microscopy using scanning probe microscope both in semicontact and contact modes at room temperature. The MCE was measured in fields of up to 1.8 T by direct method and magnetostriction was measured by the strain-gauge method in the temperature range 80 - 320 K in magnetic fields up to 1.2 T. The Curie temperature, values of MCE and magnetostriction were obtained. The relationship between magnetic properties and micro- and nanoscale structural features of samples was established.
The work is supported by the RFBR and Moscow city Government according to the research project 15-33-70040 mol_a_mos.

The hard magnetic materials play a large role in modern technology (automotive, electronics and many daily use equipment), the overview of statistics indicate that over the next few years the continuous increase of their consumption will be observed. Currently, China is the largest exporter of rare earths elements, from which RE-M magnets are produced. This situation is inconvenient for European counties because their depend on the largest producer. This situation, in addition with the high material and production costs make that the very important area of research is the investigation under the possibilities for effective recycling methods of hard magnets.
In the paper the characteristic of magnetic composite material based of RE-M-B powder will be presented. For the research, the new magnetic material had been prepared from recycled hard magnetic elements (from electric motors) and the plastic as a binding material. The magnetic material characteristic includes, a brief outline of the recovery technology (treatment and processing of recycled permanent magnets) as well as a package of materials research – SEM and X-ray spectroscopy analysis. The paper brings the opportunities to introduce the hard magnets recycling technology on an industrial scale.

Main productions of primary zinc metallurgy are ingots used to produce various goods by the methods of plastic deformation. Cooling and solidification conditions of zinc melts largely determine the crystal structure and properties of ingots. This paper shows the influence of thermal processes in the metal and mold on the quality of zinc ingots.
Ingot and mold temperature fields were studied by direct thermal analysis method. In the case of ingots solidification in molds with initial temperatures 20°С and 160°С heat dissipation from ingot caused by heat accumulation by metal mold temperature of which rises up to 180°С and 230°С, respectively. During solidification of ingots in the molds with initial temperature 310°С heat dissipation caused by heat transfer through the mold walls and the mold temperature is almost constant (310-330°С).
To evaluate the solidification characteristics of the ingots depending on the initial mold temperature used the method of liquid residue pouring in fixed time intervals by mold tipping with subsequent measurement of the thickness and weight of remaining solid crust. It is shown that the best directional solidification conditions are provided at higher temperature gradient (solidification of alloy in mold with maximum temperature 160°С). Investigation of the thermal conditions of ingots solidification showed that minimal time of full casting cycle, including pouring and in-mold ingot cooling, in absence of forced cooling is achieved at initial mold temperature 180-200°С. Since molds are used repeatedly during the shift, it is important to maintain their temperature at constant level before the next pouring.

The results of the study show that the anisotropy factor depends on the alloy structure. Deformation under superplasticity conditions can be considered to be one of the thermomechanical methods of reducing the structural and deformation anisotropy of the initially textured material. The anisotropy factor can be regarded as one of the material macroparameters that characterize the structural changes occurring in the material and can be used to quantitatively evaluate the degree and completeness of structural changes with respect to the initial state in the changing field of temperatures and strain rates.

As a pyro-metallurgical process, a fluidized-bed process can be employed because of its high transfer rates of heat and mass between gas and powder particles. The metal powder production usually needs to be divided to a few steps to obtain an effectiveness of stepwise control or to solve some operational difficulties. In these cases, a multi-stage fluidized-bed system can be used to meet different operating conditions of steps. Hydrogen reduction processes of oxides by a two-stage fluidized-bed reactor are studied in this study for the metal powder productions of molybdenum and nickel. For the molybdenum powder production, before the hydrogen reduction, a serial use of a single fluidized-bed reactor for the calcination of an ammonium molybdate to make a molybdenum oxide, is also investigated. As results, optimal operational conditions (temperature, residence time and gas consumption rate) for each fluidized -bed step are provided, as well as the process conceptions of the hydrogen reduction by the two-stage fluidized-bed reactors.

Al-based alloys are very preferred for automotive manufacture to produce lightweight vehicles. Positive effect of Sc,Zr-additions on mechanical properties in selected Al-based alloys is well known. The as-cast Al–Zn–Mg-based alloy with and without Sc,Zr-addition was investigated during isochronal annealing from room temperature up to 460 °C. Precipitation reactions were studied by electrical resistometry, microhardness measurements and differential scanning calorimetry. These measurements were compared to microstructure development that was observed by optical microscopy and transmission and scanning electron microscopy. Microstructure observation proved the Zn,Mg-containing eutectic phase at grain boundaries in the as-cast state of both alloys. It was also observed that the Sc,Zr-content is not homogeneously distributed but concentrated in randomly localized matrix regions and together with Zn and Mg in the particles at grain boundaries. The distinct changes in resistivity and microhardness curves as well as in heat flow of the alloys studied are mainly caused by dissolution of the Zn,Mg-containing Guiner-Preston (GP) zones and subsequent precipitation of the metastable particles from the Al–Zn–Mg system. The hardening effect after isochronal annealing at temperatures above ~ 280 °C probably reflects the Sc,Zr-addition. The eutectic Zn,Mg-containing phase partly disappeared during the isochronal annealing above this temperature. Precipitation of the Mn,Fe-contaning particles was also observed in the alloys. The apparent activation energy values were calculated regardless of Sc,Zr- addition as: dissolution of the GP zones (~ 115 kJ/mol), formation of the metastable (~ 130 kJ/mol) and stable Zn,Mg-containing particles (~ 145 kJ/mol). Melting of the eutectic phase was observed by differential scanning calorimetry at ~ 475 °C.

Currently, many attempts have been taken to enhance the coercivity and reduce the heavy rare-earth consumption in Nd–Fe–B sintered magnets simultaneously. Some progresses have been made in efforts to introduce Dy and/or Tb in many forms, namely, oxides, fluorides, hydrides, intermetallic compounds and alloys. The Tb3Co0.6Cu0.4 composition was suggested to apply as the efficient addition in manufacturing sintered Nd-Fe-B-based magnets. The alloy was prepared by arc melting in purified argon atmosphere and subsequently annealed at 600C for 90 h and subjected to hydrogenation. The phase composition and structure of the initial were studied by electron microscopy, electron microprobe and X-ray diffraction analyses, and Auger microscopy. The in part substitution of copper for cobalt does not change the orthorhombic Fe3C-type structure (space group Pnma) of the Tb3Co compound. The copper solubility in the Tb3Co and Tb12Co7 compounds was determined and the lattice parameters of the compositions were estimated. During hydrogenation, the Tb3Co0.6Cu0.4 composition was shown to decomposes into TbH2-3 hydride and fine dispersed (Co,Cu) mixture. Additions of the mixture (2 wt %) to Nd-Fe-B-based sintered magnets (the initial alloy (wt %) Nd-24,0, Pr-6,5, Dy-0,5, B-1,0, Al-0,2, Fe-balance was prepared by strip-casting technique and subjected to hydrogen decrepitation) allow us to obtain magnets with Br = 13. 5 kG and jHc = 16.7 kOe.

The work is devoted to the development of technology for obtaining and studying the physicochemical characteristics of oxide coatings of noble (IrO2 RuO2), rare earth (Ta, Nb, Ce) metals, and TiO2, SnO2 based on a titanium, that has undergone the primary chemistry.
Important technological characteristics (adhesion, roughness) which show the principal possibility of using the obtained samples as anode materials for the electrolysis of aqueous solutions for the purpose of purifying wastewater or the production of sodium hypochlorite as a reagent were determined. Studies conducted by the XPS, obtained microphotographs and surface profiles confirm the prospect of using these oxide coatings as electrode materials.
The electrochemical characteristics we studied make it possible to determine the field of application of the obtained electrodes more accurately for the reaction of chlorine and oxygen evolution with RuO2 and IrO2.

Microstructure and properties of joints of titanium and C45 non-alloy quality steel performed using aluminum, copper and nickel foils as interlayers were evaluated in the study. The process was carried out in vacuum in the temperature 600, 900 and 950 C for 60 min for Al, Cu and Ni filler metals, respectively. The effect of used filler metal on the joints microstructure, composition, hardness and tensile properties were analyzed by means of optical and scanning electron microscopy (SEM), electron probe microanalyses and mechanical tests. When aluminum was used as a filler metal FeAl2, Fe2Al5, FeAl3, TiAl3, TiAl2 and TiAl intermetallic phases were formed. When joined using copper filler metal, the phases present in joint were: Fe2Ti, FeTi, Cu3Ti2, Cu4Ti3, CuTi and CuTi2 containing additionally small amounts of Fe. When nickel was used as a filler metal at the at the steel/nickel interface Fe2Ti and FeTi were formed. At the nickel/titanium interface, the layer of NiTi2 was observed and the irregular shaped particles of Ni3Ti. The maximum hardness values in the range of 506 to 870 HV were achieved at the steel/aluminum interface due to the presence of the Fe2Al5 and FeAl3 intermetallic phases. The maximum hardness values at the metal/titanium interface were achieved for nickel filler metal due to the presence of the NiTi2 and Ni3Ti intermetallic phases and they were in the range of 380 to 480 HV. The maximum bond tensile strength was obtained for copper filler metal and averagely was 245 MPa, with 4.2% elongation.

The characteristics of cast aluminum alloys are shown in the paper with particular emphasis put on AlSi7Mg alloy and method of silumin modification. Heat treatments have been described to enhance the mechanical properties of cast aluminum alloy.
The work presents the melting process, modification and casting of the AlSi7Mg alloy by gravity method and squeeze casting. The paper describes the influence of solution heat treatment and ageing treatment to mechanical properties of AK7 silumin. Based on the research, it has been found that squeeze casting ensures the production of high-quality AlSi7Mg casting alloy. Modification with strontium improves the strength properties and significantly increases the elongation of gravity castings - the relative increase of A5 in these castings has reached about 40%. In all tested castings the treatments of solution heat and ageing have increased the strength of the material by 33-40 MPa. A combination of modification, heat treatment and squeeze casting allows to manufacture of AlSi7Mg alloy with high mechanical properties, Rm=280 MPa, R02=190 MPa, A5=16%.

Twin-roll cast Al-Mg-Sc alloy was submited to cold-rolling. The influence of heat treatment 8 h/300 °C on the deformation microstructure was studied by the means of transmission electron microscopy and microhardness measurements.

In the paper the differences in the structure of dental alloys have been presented. The observations of the selected commercial dental alloys (Ni-alloy and Co-alloy) structures have revealed the differences in their morphology - depending on the melting and casting conditions. In the paper the four most commonly used in dental laboratories arts are presented.

In the last 20 years the continuous casting has become a modern production technology of metals including steel, aluminium, and copper. Since cooling patterns and the temperature distribution of cast metal significantly influence the quality and productivity of final products, metallurgists utilize computer solidification models which allow them for thermal analysis, monitoring and optimization of cast products. Most of models are based on so-called interface capturing methods, e.g. on the enthalpy method which is rather simple and straightforward. The paper presents a solidification model for continuously cast aluminium which is based on another approach. The applied front tracking method offers benefits such as a higher order of accuracy and a possibility to simulate the growth of dendrites. The model allows for 3D simulations and it is based on the slice approach in which a 2D calculation slice moves through the solidifying strand. Various setup options (mesh size, casting speed, cooling scenario) of the model were considered and investigated. Results of the slice model are compared to results gained with the use of the enthalpy-based 3D model and a comparison of methods is presented and discussed.

This article describes experiments performed to assess the effectiveness of abrasive waterjet (AWJ) cutting used to cut copper. The roughness of the cut surface and the kerf widths were measured using a TOPO L120 contact profilometer and a Nikon Eclipse MA 200 optical microscope. The experiments revealed that the traverse speed of the jet was a significant parameter affecting the surface roughness and the kerf width. An increase in the traverse speed caused an increase in the surface roughness. This was particularly visible along the bottom edge of the workpiece. Higher cutting speeds were also responsible for a reduction in the smooth cutting region on the cut surface. An increase in the traverse speed caused the kerf to narrow, with the kerf width decreasing both at the top and the bottom. It is thus important to select the correct traverse speed to obtain the required surface quality while keeping the efficiency of the cutting process high.

In connection with the end of life of the first commercially produced thin-film photovoltaic panels, the issue of recycling them is very topical. One of the methods for the production of the first photovoltaic cells was thin film technology, based on the CdTe content. The work is therefore devoted to one of the possible methods of separation of CdTe and glass particles in the powder material obtained during the liquidation of worn photovoltaic panels aiming at their secondary use. For the above-mentioned separation, the method of centrifugal gravity concentration of particles was used. The influence of the separation method to a change in the mechanical and physical properties of the powder mixture, including the angle of internal and external friction or compressibility, was studied as well. A criterion for comparing the results for the separation products were the contents of SiO2 and CdTe. A partial task was also time optimization of the separation process. The original material contained 46.05 wt. % of SiO2 and 16.06 wt. % of CdTe and unit shares other oxides (CaO, MgO, K2O etc.), laminated plastic and metals. The samples were taken at 5-minute intervals. Using centrifugal gravity concentration, it was possible to obtain the final concentrate with 29.28 wt. % of SiO2 and 45.69 wt. % of CdTe during optimized process time of 20 minutes. Initial experiments demonstrated the basic possibilities of the above-mentioned material separation and differences in mechanical and physical parameters of individual products.

The mechanism of dezincification is a relatively common cause of water networks defects and is involved with the composition and the terms of the water flow. This process is a typical representative of the selective corrosion of brass when a portion of the original material from copper and zinc alloy into a spongioid copper changed. This occurs either in the full layer near the surface, or locally. Spongioid copper has no strength and step by step wall perforation of the product occurs. Dezincification also has a role in the formation of corrosion cracking of brass.
This paper deals with the problem at the heat station, after the installation of drinking water dosing of ClO2. After approximately two years the failure occurred of the some components of hot water distribution system. Most notably was the leakage of water in bodies of water gauge and other brass parts. For the assessment of the material state optical and SEM microscopy has been used, EDS analysis of chemical composition, and microhardness measurement. XRF and XRD analysis for the characterization of corrosion products. The investigation affirmed the original premise of dezincification mechanism of damage as a result of the composition of the flowing media.

The crucible furnaces are mainly used for melting metal or for keeping the metal in the liquid state. Among other things, an applicable mathematical optimization of the crucible parameters could contribute to reducing the high energy intensity of crucible furnaces. The component part of the considered mathematical model of the radiation heat transfer is the calculation of the view factors whose analytical solution is possible only in special cases. This article deals with the proposal to simplify the analytical calculation of the local view factors for the generally shaped crucible on standard conditions.

Magnesium-lithium alloy is one of the lightest metal construction material and has excellent strength and with low density. Its density is about 1.3-1.6g/cm3 and has high strength, and is an ideal structure material for aerospace, aeronautics and military industry, nuclear industry, electronic products, etc. The primary feature of Mg-Li alloys is high solid solubility of lithium in magnesium and magnesium in lithium. There are also no intermetallic phases. In the equilibrium system, there are two solid phases: a solid solution of lithium in magnesium with a hexagonal structure and a solid solution of magnesium in the lithium, characterised by a structure of a regular spatially centred. To improve mechanical properties of magnesium-lithium alloys, a different type of modifiers are added to melts to decrease grain size thus changing mechanical properties. Zirconium is one of the magnesium alloy microstructure modifier, which reduces the grain size and consequently makes it possible to obtain satisfying mechanical properties. Even a small amount of zirconium in magnesium alloys results in a complete modification of coarse-grained microstructure. The paper presents the results of the influence of commercial Zr on the refine the grain size and dilatometric behaviour of Mg-xLi-1.5Al alloys (x=4.5, 9 and 12 by weight percentage). The relative elongation and linear coefficient of thermal expansion of investigated light-weight alloys were measured in the temperature range from 20 to 400oC. The effects of Zr content on the microstructure of analysed magnesium alloys were investigated. Microstructural evaluations were identified by light microscope and X-ray diffraction.

The paper concerns the topic of tests held to control key parameters of semi-finished products and final aluminium beverage cans. As a product of a mass and precise process, cans, and at first their bodies, are controlled by a number of tests that check mechanical properties that are crucial for customers, but also visual, chemical aspects or dimensions. These tests are held not only to satisfy customers' requirements, but also to increase the efficiency of the process. The paper also suggests an idea for checking the quality of aluminium sheets from the perspective of process efficiency.

The purpose of the work has been the evaluation of flow and solidifying of AlMg10 alloy during the mould cavity filling in the spiral castability test and simulation of graphite particles movement during the filling of the mould cavity with composite suspension based on AlMg10 alloy matrix. This evaluation has been performed on the basis of computer simulation of the mould cavity filling and the solidifying of the casting held by means of the Nova Flow and Solid program. The AlMg10 alloy cast into the oil sand mould has been assumed for modelling. During the simulation changes of temperature have been registered, the solid phase fraction growth has been observed, and the changes of flow rate in the mould channel have been recorded until the flow stop. A series of figures presents the arrangement of the graphite particles during the subsequent flow stages and after the flow stop. This arrangement of graphite particles has been compared with the results of particle trajectory calculations obtained from the solution of the flow equation showed in earlier publications.

La1.5Mg0.5(Ni0.8Co0.2)7 alloy was synthesized from the sintered mixture of La2O3 + NiO + CoO + MgO in the molten CaCl2 electrolyte at 750°C. LaNiO3 and Mg0.4Ni0.6O phases formed during sintering (at 1200°C for 2 h). Both mixed oxide sinter products facilitated the La-Ni and Mg-Ni phase formations. X-ray diffraction peaks indicated that the first stable phase appeared in the alloy structure was LaNi5 which formed upon reduction of La2NiO4 phase. Increase in Mg content caused formation of La1.5Mg0.5Ni7 phase in the alloy structure and the presence of this phase improved the hydrogen storage performance of the electrodes. Carbon nanotubes (CNT) were synthesized in the molten LiCl-NaCl electrolyte at 800°C by electrolysis at 5 A cm-2 current density. The composite La1.5Mg0.5(Ni0.8Co0.2)7 alloy / CNT electrodes were prepared at various compositions. It was observed that the presence of CNTs improved the hydrogen storage performance of the electrodes considerably.

Thermal treatment of NiTi alloys allows significantly influence superelastic behavior through microstructure changes. Appropriate thermal regime is able to move austenite-martensite transformation temperatures. The aim of the work was the study of microstructure of NiTi specimens with 55.85 wt.% Ni of the wire shape before and after thermal treatment. The heat regimes were performed at this conditions: solution treatment at 600 °C for 1 hour followed by water quenching; aging at eight different temperatures (250, 270, 290, 300, 350, 400, 450 or 500 °C) for 30 minutes. Microstructures features were studied by means of optical and scanning electron microscopies, EDX microanalysis and microhardness measurement. Higher aging temperatures led to increasing microhardness and microstructure changes.

High-temperature tests of the alloys Ni3Al and Ni3Al-Mo were performed under compression. The alloys were tested in as-cast and directionally solidified state at the temperatures of 800 and 1 000 °C. As-cast samples were prepared by method of vacuum induction melting. Solidified samples were prepared from castings by Bridgman’s method. Cylindrical samples with diameter of 8 mm and length of 12 mm were subjected to compression tests under elevated temperatures. The tests were performed on the equipment Gleeble 3800. Obtained values of selected mechanical characteristics of unalloyed and Mo alloyed alloys and also alloys in as-cast and directed state were compared. Alloyed alloys in as-cast state show higher values of yield strength and maximal achieved stress. The alloys in directed state have better values of ductility corresponding to the achieved maximal stress during compression tests. Evolution of stress-strain curves under compression in as-cast samples has very similar character, when a significant decrease of tension occurs at the achieved deformation of 0.15. In the case of directionally solidified samples this evolution depends on created structure and temperature of testing.

The large coercivity (Hci ≈ 4000 kA/m at 20 K) in melt spun Nd-Fe alloys is results from different nonequilibrium hard magnetic phases in amorphous and partially crystalline ribbons. One of the main difficulties of the macroscopic magnetization analysis of the Nd-Fe alloys is the impossibility to extract the contributions of Fe and Nd ions and phases to the total magnetization of the alloy. In recent years X-ray magnetic circular dichroism (XMCD) method has become as a powerful tool for microscopic magnetic characterization of the due to its atomic selectivity properties. XMCD technique gives possibility to separate the contribution of Nd and Fe-Nd phases in magnetic behavior of the Fe-Nd alloys.
We present the XMCD analysis of melt spun Fe50Nd50 samples performed at L2,3-Nd and K-Fe absorption edges at 5 and 50 K in comparison with macroscopic data of magnetic properties measurements. The XMCD studies have been performed at the beamline ID 12 of the European Synchrotron Radiation Facility (ESRF), Grenoble, France, which is dedicated to polarization dependent X-ray spectroscopy in the photon energy range from 2 to 15 keV. We have measured the magnetic field dependence of XMCD signal of the melt spun Fe50Nd50 ribbon in magnetic fields up/down to 17 T. The obtained results pointed to the strong difference between phase structure and magnetic properties of the melt spun Fe50Nd50 alloy for the both macroscopic and local measurements. The element selective XMCD loops for melt spun alloy show the almost identical value of the coercive force Hci for L2-Nd and K-Fe edges. XMCD loop at K-Fe edge is a sum of contributions of the Fe-based phases. In Fe50Nd50 alloy the main Fe-rich phase a highly anisotropic phase which has Hci ≈ 2,4 T at room temperature. The absence of the K-Fe XMCD loop saturation in the field up to 17 T points to presence of the second Nd-rich Nd-Fe phase which is ferromagnetic at lower than 50 K temperature. Accordance to the TEM results the three phases may coexist as the mixture of nanocrystals which was formed as a result of decomposition of the amorphous-like matrix phase. The XMCD loop at L2-Nd edge with Hci ≈ 1,9 T arises as the sum of contributions from three Nd-based phases: hard Fe-rich phase (Hci ≈ 2,4 T), Nd-Fe matrix phase of medium hardness with Hci ≈ 1,3 T and nanocrystals of Nd. The macroscopic loop showed a higher Hci in compare with XMCD loops, because of the XMSD loop is obtained from a thin surface layer 5-10 mkm in thickness, which contents many defects that reduce anisotropy and coercivity.

In the paper there are presented preliminary results of microwelding thin sheet of superalloys Hastelloy X and Haynes 230®. The studies determined the basic parameters of microwelding superalloys thin sheet. In this paper, welding connections of examined superalloys free from cracking was obtained and its microstructural growth characteristic was investigated. Welding of thin metal sheet was made by resistive pulse microwelding with use of a SST WS 7000s device. The study focused on the leading investigated parameters such as microhardness and the obtained weld microstructure observation. Microhardness measurements of the joints where taken using Matsuzawa Vickers MX 100 type with applied load 100G (0,98 N). The joints were examined using metallographic microscope Nikon Eclipse MA200. The survey indicates that although many studies have been performed, there is still a considerable need to further examine how to obtain satisfying quality joint, using micro welding between the thin sheet from superalloy Hastelloy X and Haynes 230®.

The AlSi17/Mg joints under analysis were produced by diffusion bonding. They contained intermetallic phases, which were a result of diffusion occurring at the AlSi17/Mg reactive interface. The microstructure and thickness of the bonding zone were dependent on the heating temperature. Two temperatures were analyzed: 420 oC and 440 oC. The bonding zone produced at the lower temperature was thinner (50 μm). It was composed of an Al3Mg2 intermetallic phase (observed on the AlSi17 side), an Mg17Al12 intermetallic phase (observed on the Mg side) and an Mg2Si phase. In this case the Mg2Si was irregularly distributed over the Al-Mg intermetallic phase matrix. Fine particles of Mg2Si phase were observed in the region adjacent to the AlSi17 and large areas of this phase were visible locally near large Si particles. When the temperature of the diffusion bonding process was higher, a much thicker bonding zone (about 400 μm) formed. The structural constituents detected there were: Al3Mg2 (on the AlSi17 side), Mg17Al12 and a solid solution of Al and Si in Mg (on the AZ91 side) and an Mg2Si phase. The distribution of the Mg2Si phase in the bonding zone was more regular; fine particles of this phase were visible all over the bonding zone.

There was performed a comparative analysis of sound emitted by two identical bells cast of bell bronze at different pouring temperatures. The influence of pouring temperature on the change of sound, the structure, and the porosity of castings was assessed. The obtained results were compared with the simulation results concerning vibration of numerical models received from the SolidWorks program.
It was proved that the higher pouring temperature results in the reduced porosity of a bell casting with the simultaneous improvement in the quality of sound thanks to the revealing of the basic constituents of sound demanded for bells (hum, prime, tierce, nominal). The vibration frequency range of a bell poured from the higher temperature was confirmed by simulation results.

Exploration for biocompatible materials with improved mechanical properties imposes a change in the chemical composition of the (α+β) titanium alloys used in the modern implantology. The increased quantity of some toxic alloying elements could eventually cause undesirable biological effects in the human body. The high Al content could lead to reduced implant in vivo survival. Simultaneously, the low Al concentration will decrease the mechanical strength of the alloy but the alloy is expected to have lower cytotoxicity and improved plasticity. The present study aims at determining the maximum vacuum heat treatment response at various regimes of quenching and aging of Ti-5Al-4V alloy. For this purpose the critical limits for the heat treatment regimes are defined according to the microstructure, XRD analysis and Vickers hardness test results and they are taken into account for determining the optimum regime.

The effect of Mo addition (x=0-5 at%) on the evolution of microstructure and mechanical properties was investigated in an AlCoCrFeMoNi eutectic high entropy alloys (EHEAs) system. Calculated phase diagrams were used to determine the eutectic composition of the alloys. EHEAs were prepared in vacuum arc melting furnace under argon atmosphere and casted in a metal mold. The alloying effects on phase constituents and fractions were examined by X-ray diffraction (XRD) and Rietveld refinements. The microstructures of the alloys were investigated by scanning electron microscopy (SEM). Room temperature compression tests and Vickers hardness measurements were performed for mechanical characterization.

Nanostructured Nd-Fe-B alloys, obtained by their rapid quenching (RQ), are widely used as fillers in high magnetic energy product bonded permanent magnets. The objects of this investigation were commercially produced RQ alloys based on Pr2Fe14B (MQP-16-7) and Nd2Fe14B (MQP-B, MQP-B+) phases. Preliminary studies have shown that the magnetization of these samples does not reach the saturation even in magnetic field of 70 kOe. The purpose of this work was to study the magnetic properties of nanostructured rapidly quenched alloys of the Nd(Pr)-Fe-B system in a high magnetic fields up to 600 kOe. The measurements were carried out both on free powders and on the bonded powders previously oriented by an external magnetic field of 15kOe. From the X-ray patterns analysis using the Selyakov-Scherrer formula for X-ray peaks broadening interpretation, the grain sizes of the main 2-14-1 phase in the original RQ alloys were determined. Their values are 27, 25 and 24nm for the MQP-16-7, MQP-B and MQP-B+ alloys, respectively. It is established that the grain size in the alloys studied is close to the absolute single-domain value. At 150kOe, the magnetization field dependence of the MQP-16-7 alloy exhibits a jump, explained by a first-order magnetic phase transition in the Pr2Fe14B phase. Similar magnetization jumps in MQP-B and MQP-B + alloys have not been detected. The saturation magnetization magnitudes of the alloys were found to be 172 emu/g for the MQP-B and MQP-B+ alloys and 170 emu/g for the MQP-16-7 alloy.
Supported by RFBR, pr.16-33-60226 mol-a-dk and by RF MES pr.3.6121.2017.

Biocompatible β-titanium alloy Ti–35.3Nb–7.3Zr–5.7Ta–0.7O (wt.%) shows high strength and lower elastic modulus when compared to commercial alloys for total joint endoprostheses (e.g. Ti-6Al-4V). However, in the as-cast condition, porosity, dendritic inhomogeneities and coarse grain structure negatively influence mechanical properties and therefore sequential thermo-mechanical treatment is necessary. Studied material (as-cast rod) was processed by hot rolling at 1200°C and three states with different diameter reduction were prepared. Scanning electron microscopy (SEM) and electron back-scatter diffraction (EBSD) were employed to characterize resulting microstructure. Tensile tests and microhardness measurements were used to evaluate room temperature mechanical properties. SEM showed that porosity is removed by hot rolling and EBSD revealed deformed grain structure that is partially recrystallized in the center of each rod. There is a clear difference between the grain size of the three states. Crystallographic texture was found and can possibly be used in designing final joint implants. Yield strength exceeding 1050 MPa, ultimate tensile strength of values over 1200 MPa and ductility > 25% in all three studied states indicate that hot-rolled Ti–35.3Nb–7.3Zr–5.7Ta–0.7O alloy can be used for implant manufacturing.

The paper deals with the optimization of manufacturing of cast metal foams and possibilities of using of this specific material. It is focused on castings from aluminum alloy with a regular arrangement of internal cells. The optimization relate to already used casting technologies - production of metal foams using sand cores. Casting of metal foams have a wide range of applications such as: automotive, aerospace, construction, energy. They have unique properties thanks to reduced weight with sufficient strength and they are used e.g. for: absorbing impact energy or heat conduction. In this article we deal with the usage of the metal foam as a heat exchanger. The shape and size of heat exchanger depending on its effectiveness by using a simulation program is solved.

The investigation of formation of structure of the high strength aluminum alloy based on Al-Zn-Mg-Ni-Fe system during different rolling methods was conducted. A flat ingot was subjected to hot rolling and cold rolling with obtaining a thin sheet with reduction ratio 40. A cylindrical ingot was subjected to radial-shear rolling with obtaining a calibrated rod with reduction ratio 8.16. Microstructural investigations showed that iron and nickel are joint into the equilibrium eutectic-formed Al9FeNi phase on all stages, and non-equilibrium T phase has no influence on technological plasticity. A hardness measure showed significant strengthening after rolling and precipitation ageing in mode Т6 and T4. ACKNOWLEDGEMENTS: This work was supported by the Council on Grants at the President of the Russian Federation for financial support of leading scientific schools (grant no. NSh-9899.2016.8).

The aim of the present work is to improve the quality of the single crystal permanent magnets based on the Ticonal 9 alloy (35 % Co, 14 % Ni, 7 % Al, 5 % Ti, 4 % Cu, Fe the rest) applied in the precision instruments of the space techniques. The alignment, configuration and structural perfection of the Ticonal 9 based single crystal magnets with different magnetic characteristics have been studied in the work. Single crystals grown of the melt by the directional controlled solidification method with the seed crystals having the [001] alignment were used. Single crystals underwent standard heat and magnetic treatment (HMT) but had various parameters of the induction distribution on the poles. X-ray structure analysis and x-ray diffraction topography allowed to study the crystal structure of the alloy after the HMT, to determine the lattice periods of the α - and α/- phases, to reveal two different pencil-like and plate-like configuration types. Small randomly aligned crystals have been found. The single crystal structure is correlated to the induction distribution in the air gap on the magnet poles. The results of the study allow to improve the single crystal production technique.

The strength and hardness in some metal or alloys may be enhanced by the presence of extremely small and uniformly dispersed particles within the original phase matrix. The aim of this paper was to prepare and characterize the Cu-(0.2-0.4)Cr-(0.05-0.1)Nb (wt.%) alloy strengthened by the high melting point intermetallic compound Cr2Nb. This phase is stable in solid and liquid Cu up to temperatures above 1600 °C and contributes to the microstructural stability of the alloy during its application at elevated temperature. Both, chromium and niobium has a minimal solubility in solid Cu, which limits the decrease in conductivity. This alloy was produced by combination of plasma arc melting and vacuum induction melting and formed into wires of diameters 0.3 and 0.5 mm. The structural properties and chemical composition was evaluated using scanning electron microscope JSM-7600F equipped with a WDS spectrometer INCA and the high-resolution field emission gun-scanning electron microscope QUANTA 450 FEG equipped with an energy dispersive X-ray analyzer APOLLO X. The samples were submitted to the tensile and micro-hardness testing. The Cr2Nb precipitates were fairly uniformly distributed in Cu-matrix and their mean size was about 1 um. The ultimate tensile strength of wires was substantially increased in comparison to an unalloyed copper wire.

Microstructures, properties and technical parameters of the welds carried out by the electron beam welding (EBW) process have been investigated in thepresent paper. Electron beam welding (EBW) is a fusion joining process particularly suitable for the welding titanium. Electron Beam welding is a natural choice for use with materials susceptible to oxidation such as titanium because the EB welding process must occur in a vacuum.During research a two-pass welding technique was developed. In paper there was investigated the electron beam welded joint made of pure titanium. The weld qualification was carried out by mechanical properties and microstructure evaluations were carried out to ensure the joint integrity.
Microhardness measurements of the weld where taken using Matsuzawa Vickers MX 100 type with applied load 100G (0,98 N). Light microscopy Nikon Eclipse MA200 was used for examination of the microstructure and determination of the size of the specific joint zones.

We have investigated changes in structure, phase and chemical composition caused by surface melting of Inconel 713 LC by electron beams and laser under vacuum and N2 atmosphere. Information on structure and phase composition was obtained by optical and scanning electron microscopy, X-Ray Powder Diffraction. The chemical composition was investigated by Glow Discharge Emission Spectroscopy (GDOES) and EDX. The results show that the structure and phases of the melted layer agree with the original one but the chemical composition exhibits changes in content of some elements.

The purpose of this study is to compare the dissimilar joints of pure titanium to stainless steel achieved by different intermediate materials like aluminum, copper and nickel. Due to the metallurgical incompatibility between those base materials, it has been very difficult to produce reliable joints due to the formation of FeTi and Fe2Ti types of intermetallic compounds. The purpose of using the intermediate material is to reduce and even block the diffusion between titanium and stainless steel. The thickness of those filler metals were 100 μm. The microstructure of the joints were investigated using scanning electron microscopy equipped with an energy dispersive X-ray system (EDS) to determine chemical composition of joint. The maximum values of tensile strengths was obtained for samples prepared using copper as a interlayer. The highest impact energy was achieved for joints performed using aluminum as a filler metal. SEM characterization of the fracture surfaces of the joints show that the character of fractures are brittle for the samples achieved by copper, nickel and quasi brittle for the specimen prepared by aluminum. The galvanic corrosion test was carried out in a 3,5% NaCl solution. The potentiodynamic polarization curves show that the higher corrosion potential as well as a lower corrosion current was registered for the joints performed by nickel.

Ion implantation and plasma technologies have been proved to be useful techniques to control structure and surface properties of titanium-based materials. In this work the different properties such as microstructure, phase composition, hydrophilicity, microhardness, Young’s modulus and their influence on the biocompatibility of Ti-based coatings (nitride, oxynitrides, pure and phosphorus ions implanted oxide) produced by metal plasma immersion ion implantation and deposition (MePIIID) were investigated. The phase composition and correspondingly surface properties of the layers were strongly dependent on the partial pressure of the working gases (oxygen and/or nitrogen) in the vacuum chamber. Very homogenous deposition of the stoichiometric hydroxyapatite in simulated body fluid (SBF) on Ti-based layers, produced with MePIIID technology have been found for the Ti oxynitride coating with average atomic composition TiN0.4O1.6, consisting mainly of amorphous Ti oxide with nitrogen substitution.

This paper presents a method for manufacturing stellite balls of valve pairs of sucker rod pump with a fine-grained structure using an internal cooler. The mathematical calculation and the conducted experiment showed that the complete fusion of the internal cooler with the metal to be poured occurs at a ratio of the diameter of the stellite ball to diameter of inner cooler of 1:0.8 with an insignificant overheat of melted stellite (80-100 °C) and heating the form to 400-480 °C. Brass of grade СuZn10 was chosen as a cooler. It has a density close to the stellite, approximately equal to 8.8 kg/m3. With these parameters, the internal cooler is completely fusion with stellite to a depth of 0.3-0.5 mm. Due to the presence of the internal cooler take place the grinding of the stellite structure, which in turn leads to a reduction in the number of defects during further machining.

Flat cold rolled aluminium products and its alloys find wide applications in the construction industry, electrical engineering industry, household appliances, automotive industry, etc. Diversity of potential applications translates into diversity of requirements for the properties of sheet metal. Some of the properties are essential for many applications, while others are essential only for selected applications.
As a result of the casting process of aluminium alloys designed for the rolling process, in the case of aluminium alloys we are dealing with segregation processes of chemical composition and structure.
Under the conditions of non-equilibrium crystallization, non-equilibrium and fragile phases are formed, which are a significant limitation in the process of processing. For this reason, the homogenisation treatment is often required for aluminium alloys, which, on the one hand, eliminates the effects of segregation through the diffusion, and, on the other, leads to phase transformations.
The article presents the effect of the homogenization process of EN AW 1050 ingots on mechanical and electrical properties. The evaluation of mechanical and electrical properties, as well as the micro structure, was carried out on materials after various high temperature heat treatment sequences. The analysis of the results of the tests was aimed at determining the correlation between the parameters of the homogenization process, i.e. temperature, time and micro structure, and properties of the materials after heating.

AA 6101 wire alloy has been used in the electric transmission lines in ENICAB company of the cable industries of Biskra (Algeria) for several years. In this study, the AA6101 alloy was subjected to recrystallisation annealing treatment at 400°C and holding for 30 min, this heat treatment has an effect on the mechanical and electrical properties of drawn AGS wire. The Recrystallization annealing treatment causes a microstructural modification of the textured form, which caused the softening of the wire, that is to say an increase of ductility. Characterization methods used in this work is: The Electron Back Scattered Diffraction EBSD, X-Ray diffraction, Vickers microhardness, Tensile test, Measuring electrical resistivity, the Scanning Electron Microscope (SEM) and Energy Diffraction Spectrum (EDS).

The precipitation kinetics of the GP zones in a supersaturated solid solution depends on the level of its supersaturation which induces a driving force. The magnitude of this driving force increases with the increasing of the undercooling and the increasing of the solute supersaturation. At a given temperature, the increasing of the supersaturation accelerates the precipitation of the GP zones. In an Alxat.%CU/mg alloy, the transformation kinetics depends on the contribution of the driving force and on that of the thermal activation which is preponderant.

In the field of powder metallurgy is necessary characteristic of metal powders for designing technological processes within transport, handling and storage. This paper is focused on the study of three metal powders CrCNiCr, NiCrBSi, WCCoCr, which are used for technology high-speed thermal spraying HVOF (High Velocity Oxy-Fuel). This technology is used by the SERVIS ARMATUR company, in their own production program. SERVIS ARMATUR company cooperates with the Bulk Solid Centre, VSB-Technical University of Ostrava in the field of metal powders characterization. Each one of three samples were subjected to detailed analysis. The analysis included a measurement of mechanical and physical properties such as particle shape, particle size distribution, angle of internal friction, compressibility, aeration, porosity and bulk density. Some recommendations for production were determined based on the results of physical-mechanical tests. Primarily storage, handling and dosage to the diffuser were improvement achieved.

The paper deals with the aluminium honeycomb that is very successfully used as applications in the transport industry and engineering production. Based upon its ability to absorb the large amount of energy, aluminium honeycomb has also found its utilization as the kinetic energy absorber. At low weight it has quite high compressive resistance and bending stiffness. The focus of this paper was to determine material behavior at impact loading and that is why the whole experiment was carried out on the special device (drop weight tester – drop tower), which makes possible to define magnitude of impact rate on the testing sample. As an observed factor there was magnitude of force and strain arising from the impact test. Based upon these values is possible to determine magnitude of absorbed energy by the honeycomb sample. Tests were performed by means of the visual analysis on the particular samples and by the quantitatively expression of measured data as graphs.

Titanium alloys such as Ti-6Al-4V are applied in production of structural parts mainly in aircraft and automotive industry, mostly due to favorable relationships between density and mechanical properties as well as good corrosion and crack resistance. Nowadays the most common process of plastic deformation of this material at the industry is hot forging. In search of cost reduction, powder metallurgy method is very promising, because of potential benefits like more precise control of process parameters. In this respect, determining the parameters of thermo-mechanical processing is crutial due to low formability of Ti-6Al-4V alloy.
This paper presents the results of the physical modeling of hot forging of cast and P/M Ti-6Al-4V alloy. Both types of the billets were subjected to hot compression tests using the Bähr MDS 830 thermo-mechanical simulator, under various thermal and strain-rate conditions. The microstructures of the samples manufactured by casting and machined from the compacts were observed and compared after deformation. Moreover, the results of the hardness measurements showed the relationships between the conditions of hot deformation and strengthening of the materials. In the result of the investigations, the favorable combinations of thermo-mechanical parameters of Ti-6Al-4V alloy processing were determined.

The paper presents results of research on a new type of copper component that enables the production of Cu paste.
Two pastes were applied during investigations: 1. Pv19B - commercial paste manufactured by Du Pont, 2. experimental prepared that content of more than 50 % copper. Investigations were made of electrical properties of solar cells, with front metallization made non-conventional way (using template) on computerized Solar – Lab positioning table, consisting in measurement of I-V curves of the photovoltaic solar cells. The specific contact resistance of front metallization of solar cell was measured also onto measuring position Corescan.
Using the presented results, we can reduce the cost of silicone metallization by 50%, replacing the previously used silver with cheaper copper (CuXX).