Seznam abstraktů 2022: POSTEROVÁ SEKCE E

In the last years, immiscible alloys have gained significant attention, mainly due to the use of their immiscible nature for the preparation of new advanced multiphase alloys. Most of these alloys are based on the Cu-Fe system. The advantages of Cu and Fe elements are their easy availability and low price, good mechanical properties, and medium melting temperature. Currently, most bulk Cu-Fe-based immiscible alloys are produced by casting. However, this method requires several additional steps to obtain appropriate microstructure. An interesting alternative is powder metallurgy, which provides an easy way to produce immiscible alloys with very fine heterogeneous microstructure. An essential requirement is to prepare a milled powder with a sufficiently small particle size, which consists of a metastable solid solution of all elements. The small particle size allows achieving full density during sintering, in which supersaturated solid solution decomposes into a fine dual-phase microstructure.
In this work, two sets of milling conditions (“soft” and “hard”) for the preparation of CuFe powders were tested. They differed in the milling speed and the size of milling balls. The milled powders were analyzed after several milling times and the evolution of powder particle size, morphology, and microstructure were evaluated. Based on the results, optimal milling times were selected for both sets of milling conditions and these parameters were verified by the preparation of new CuFe milled powders. Surprisingly, different results were obtained as the resulting powder particle sizes were significantly larger.

We follow an Alnico alloy sample to non destructive testing using X-ray radiography. X-ray Computed Tomography (CT), also widely known as MicroCT, is a proven method for not only checking the structural integrity of casting parts - for example for porosity - but also for checking a dimensional accuracy. It is important for assessment casting with complex or small internal areas that could not be inspected by conventional measurements without failure of the final products. Moreover, we were able to visualize the internal defects of the different shapes of casting objects. The gray-value contrasts of the CT images were excellent to distinguish the resin material in the alloy samples. This will be a useful qualitative and quantitative advancement to rapid and detailed non-destructive analysis within the die-casting industries in improving the quality of the alnico alloys.
ACKNOWLEDGEMENTS: The research reported herein was supported by a grant from the National Centre for Research and Development. Program: Lider XI, grant title: "Improvements in the technology of machining the surfaces of spherical rings of magneto mirrors through the use of electro-erosion machining (EDM)", contract number: LIDER/59/0246/L-11/19/NCBR/2020.

Compacting pressure applied during the SPS method varies in the literature. This study evaluates the influence of the applied compacting pressure during the SPS by evaluating the microstructure and porosity of sintered materials. This work focuses on preparing bulk magnesium materials from cold compacted magnesium powder (green compacts) using spark plasma sintering (SPS). The green magnesium compacts were prepared at room temperature using 100 MPa of uniaxial pressure, which was applied for 60 s. The green compacts sintering was carried out at 400 °C for 10 min using SPS. During sintering, the applied compacting pressures were 20, 40, 60, 80 and 100 MPa. The experimental materials were evaluated in terms of microstructure and porosity. The resulting microstructure and porosity strongly depended on the compacting pressure applied during SPS.

The aim of the work is a proposal of innovative technology of metal waste processing - sludges and filtration cakes from galvanizing plants. The paper deals with possibilities of zinc obtaining from waste of galvanic sludge, which arises during galvanic plating. A leaching process in a sodium hydroxide environment was optimized in the laboratory, resulting in separation of zinc from iron and other organic an inorganic components from sludge. The obtained leach was processed by means of the electrolysis in order to get pure zinc. The stainless plate was used as a cathode, nickel plate as an anode. Results of chemical analyses of individual middlings and final products at the hydrometallurgical processes are presented in the article.

Aluminum, like other technically pure metals, at 99.5% and more, has poor mechanical properties (low ductility and hardness). And for this reason, from the end of the 19th century, metallurgists sought to improve their properties by adding other elements.
Recent work has shown that modifying the chemical composition of Aluminum alloys with the addition of other elements such as Cu, Mg and Zn could lead to an improvement in their ductility and hardness (at the same time) even at low temperature by playing on the crystallographic texture in principle and in another way on the crystallographic sliding systems.
The directional dependence of the properties of the material means the anisotropy, it can be described by a physical quantity thus indicating the degree of drawability of the material which is the Lankford coefficient. The characterization of the anisotropy is done by calculating this coefficient by different experimental techniques using tensile tests.
Using the tensile curves corresponding to alloys of the 1050, 2024 and 7075 series, constants can be determined corresponding to each hardening model studied (hollomon, Swift and Voce).

The article analyzes the presence of selected metals, classified as Technologically Critical Elements (TCE), in electrical and electronic devices. Metals belonging to the group of critical metals (German), strategic metals (Tellurium) and very toxic elements (Thallium) were analyzed. Due to the low content of these metals in e-resources, these metals are usually ignored during e-receive analysis. This means that these metals belong to the least known metals in the literature on waste recycling. Their presence in e-waste can cause them to focus in the environment during improper processing of e-waste. The article discusses electronic components in which Ge,Te, Tl, and analysis of the possibility of entering the environment during recycling processes, are found.

The technology of casting thin-walled castings requires increased demands on the stability of technological processes and pressure casting parameters. The wall thickness of the studied zinc alloy castings (ZP0410) ranges from 0.4 to 1.2 mm. In general, it is necessary to use higher mold operating temperatures and a higher casting speed when filling the mold cavity when casting thin-walled castings. There is an increased load on the mold (tool) and the casting machine during this casting process and the use of more demanding parameters. It results in a shortening of mold service life.
There is currently no own returnable material (alloy ZP0410) used in the given production conditions in the production of thin-walled castings. Only the primary alloy ZL0410 is used now. It must be emphasized that the ability to implement the recycling of these returnable materials is becoming increasingly important. However, it is necessary to ensure that the quality of production is not reduced.
The research was carried out aimed at determining the current state. Methods of roughness analysis, computed tomography, and metallography of casting defects from casting machine failures even after plating are used in the study of existing production technology in addition to standard long-term monitoring of melt quality. The findings of these research activities were briefly summarized in the paper. The experimental development of the technology of using our own returnable material in this quality-intensive production is in progress now.

It has been found in recent years that the conventional Manson-Coffin law tends to overestimate the fatigue life at high levels of plastic loading. Such reduction in fatigue life is associated with a fundamental change in the mechanism of damage accumulation. Deterioration of the structure by cracks propagation becomes marginal and the fatigue resistance is governed by the ductility exhaustion phenomenon. The plastic deformation ability under extremely low cycle fatigue conditions is generally related to the occurrence of secondary phases, ie inclusions and precipitates, dispersed in the matrix. This study investigates the microstructure of hardenable 2024 aluminum alloy and its effect on the cyclic response in the extremely low cycle fatigue region. Metallographic samples of the studied alloy were probed using SEM/EDS and EBSD analysis to identify the morphology and chemical composition of the observed phases. Fatigue tests were conducted in a symmetrical push-pull regime under strain control at room temperature and cyclic plasticity and S-N curves were determined. Electron microscopy observations revealed anisotropic microstructure with numerous fragmented inclusions. Fractographic analysis showed that these hard and brittle secondary phases act as an effective microstructural flaw leading to strong plastic damage accumulation and subsequently to fatigue cracks nucleation. In terms of fatigue life curves, a huge discrepancy in the fatigue data was observed at the extreme levels of cyclic straining. To overcome this shortcoming, a new three-parameter regression function was successfully employed and the obtained results were further discussed.

Magnesium-intermetallics laminated composites have been fabricated through reactive bonding at 490°C in vacuum using magnesium sheets and copper foils. Investigations were concerned with the structural transformations of a Mg-Cu couple boundary. Holding for only a few minutes resulted in the formation of thin layers at the investigated interface. Prolongation of the heating time lead to reactions in the liquid state and completely disappearing of copper layers. Therefore, the final microstructure consisted of alternating layers of unreacted magnesium and intermetallics. The microstructure was revealed in optical and scanning electron microscopy (SEM). The study exhibited the presence of different reaction products in the diffusion zone and their chemical compositions were determined by X-ray microprobe analysis. The occurrence of two different intermetallic compounds Cu2Mg and CuMg2 was predicted from the Cu-Mg binary phase diagram. The predominant part of the intermetallic layers was the hypoeutectic mixture of CuMg2 and solid solution of copper in magnesium, since a liquid front of reaction was moving into the magnesium sheets. The microhardness of the reaction products and the elemental components was comparatively measured.

Nowadays, implants are mainly made of metallic materials. Metallic implants have two main problems. The first is the modulus of elasticity, which is higher than the modulus of elasticity of the human bone, which leads to the phenomenon of stress shielding and subsequent implant failure. The second problem is the inability of biodegradability, which leads to inflammation of the surrounding tissue due to the release of cytotoxic ions during the corrosion process of the implant. That is why recent research has focused on the development of metallic materials that are biodegradable, biocompatible and whose modulus of elasticity approaches the modulus of elasticity of human bone (10-20 GPa). The development also focuses on surface treatment and thermo-mechanical treatment of these alloys in order to increase biocompatibility, mechanical properties and reduce the rate of degradation. The aim of this work was to prepare the new biodegradable alloy on the base of Mg-Ca-Zn-Mn and study the influence of thermomechanical treatment on the alloy microstructure, phase composition, microhardness and corrosion properties. Homogenization annealing was performed at 480 °C for 24 h followed by water quenching. The material was subjected to one pass of equal channel angular pressing (ECAP) at 290 °C. Microstructure study was performed for as-cast, heat-treated and ECAPed conditions and was accomplished by microhardness measurement. The chemical and phase composition was observed using of a scanning electron microscope and EDX analysis. To determine the corrosion properties of the alloy, an immersion test was performed together with the measurement of potentiodynamic curves.

The immiscible Cu-Fe system is often used as a base for advanced heterogeneous alloys. With a suitable selection of alloying elements, it is possible to alloy individual phases, and therefore tailor the microstructure and final properties of a material as needed. To prepare the mentioned multicomponent alloys, it is necessary to understand the effect of individual alloying elements on the microstructure and properties of the Cu-Fe system. Although mostly used method in the production of such materials is casting, mechanical alloying appears to be a suitable alternative, enabling a very fine microstructure to be created.
The following study is focused on the characterization of Cu50Fe25Cr25 and Cu50Fe25Ni25 alloys and the effect of the alloying elements on their microstructure. Cr and Ni were selected as a BCC and FCC phase enhancing elements, respectively. The alloys were prepared by mechanical alloying using high-energy ball mill, with subsequent densification using spark plasma sintering. The microstructure of milled powders, as well as bulk samples, was examined, and the evolution of the microstructure during sintering was evaluated with respect to the alloying elements. In addition, the hardness of bulk samples was measured. During the mechanical alloying a complete mixing was not achieved, as the milled powders were not single phase. However, a metastable FCC supersaturated solid solution was formed at least partially in both alloys, further decomposing into a multiphase microstructure after sintering.

Although simulated exposure to corrosion environment using laboratory artificial ageing processes (both in the climatic and corrosion chambers or using different simulated approach) is standard procedure to evaluate corrosion behaviour of materials in the environment. The simulation have to be comparable to the real exposure environment to produce comparable results; yet more aggressive to produce these results in shorter time period.
To obtain results that could be compared both in the phase composition of corrosion product and coorosion speed thus corrosion processes occuring are mostly the same research team have to compare laboratory simulation with data obtained from real exposure sites. If the complex model of corrosion should be build researchers have to include as much as possible data from as much as possible diverse exposure sites.
For the enhancement both in the field of heritage protection and ISO standard improvement precise corrosive agents identification is manadatory. To postulate siutable set of artificial ageing simulations using climatic chamber with corrosive agents addition, diverse environments were carefully chosen according to previous corrosion conditions monitoring. Then corrosion environment has been analzyed in those sites to identify corrosive agents; both direct and indirect.
As a complex result sets of simulation conditions have been identified to further specify whether or not any synergetic effect may apply. And finally digested into improvements for both cultural heritage preservation methods and ISO standard, where Lead coupons are suitable monitoring option for the VOC/TVOC in the depositary and exhibition areas and also corrosivity classes have been refined according to results obtained.

Quinoline sulfonamide complexes with different metals represent a new class of materials of great interest especially for their fotoluminiscent (mostly fluorescent) properties and biological activity ( these include mostly antiprotozoals, antibacterial and antifungal activity). The emphasis of this work was to synthesize, characterize and determine the biological proprieties of new materials for medicinal chemistry applications based on quinoline sulfonamide complexes metals. The synthesis of the newly materials is straight and efficient, involving two steps: acylation of aminoquinoline followed by complexation with M2+ metal (metal acetate for Cd2+, Co2+, Cu2+, respectively metal chloride for Zn2+). The synthesized materials were characterized by FTIR and NMR spectroscopy and by X-ray diffraction on single crystal. The obtained materials were tested for their antibacterial and antifungal activity, with very promising results. Some of quinoline sulfonamide complexes metals have an excellent antibacterial activity against gram positive bacteria Staphylococcus aureus ATCC25923 (with a diameters of inhibition zones in the range of 20-30 mm and a MIC of 20-25 x10-5 mg/mL), a very good antibacterial activity against gram negative bacteria Escherichia coli ATCC25922 (with a diameters of inhibition zones of 20-25 mm and a MIC in the area of 500 x10-5 mg/mL), and an excellent antifungal activity against fungus Candida albicans ATCC10231 (with a diameters of inhibition zones in the area of 25-30 mm and a MIC in the range of 15-20 x10-5 mg/mL). The obtained data reveal that some of the obtained quinoline sulfonamide complexes metals are promising leading drug candidates.
Acknowledgements: Authors are thankful to Romanian Ministry of Research, Innovation and Digitization, Program 1-Development of the national R & D system, Subprogram 1.2—Institutional performance—RDI excellence financing projects, Grant no. 11 PFE/30.12.2021 and CNCS-UEFISCDI, project number PN-III-P4-IDPCE- 2020-0371, for financial support.

Fluorescent small organic molecules with near-infrared (NIR) fluorescence, including the first near-infrared region (NIR-I, 650-900 nm), has attracted increasing interest in the biomedical applications from in vivo imaging to in vivo cancer therapy, due to their unique characteristics, such as high flexibility and precision, great tissue penetration, minimal tissue absorption and emission light scattering, and low autofluorescence. Of particular interest are fluorescent small organic molecules with fluorescence in the region 650-700 nm, the so called “medical optical window”. These molecule are usually large π-conjugated derivatives or electron donor-acceptor (D-A) structures, fused azaheterocycles with extended conjugation being particularly of interest.
The emphasis of this work was to synthesize new fused conjugated azaheterocycles with four to six rings and, to characterize and determine their fluorescent proprieties in order to be used as fluorescent building blocks for biomedical applications. The method of synthesis is straight and efficient, involving only 2 steps: alkylation of benzo[f]quinoline followed by a 3+2 cycloaddition reaction. According with the number of the conjugated fused azaheterocycles rings and fluorophores used as substituents of the rings, the fluorescence emission spectra are in the region of 450-500 nm for compounds with 4 rings, respectively 550-600 nm for compounds with 6 rings. These preliminary results make us confident that choosing rationally others fluorophores, the fluorescence emission of our fused azaheterocycles could be pushed bathochromic in the region of medical optical window, 650-700 nm.
Acknowledgements: Authors are thankful to Romanian Ministry of Research, Innovation and Digitization, Program 1-Development of the national R & D system, Subprogram 1.2—Institutional performance—RDI excellence financing projects, Grant no. 11 PFE/30.12.2021 and CNCS-UEFISCDI, project number PN-III-P4-IDPCE- 2020-0371, for financial support.

Cobalt superalloys based on the Co-Al-W system are a new group of heat-resistant materials, which have attracted attracted the interest of researchers in 21th century. The advantage of the new materials over conventional cobalt alloys is the strengthening mechanism based on a microstructure of the γ-γ′ type with a low value of the lattice mismatch between the phases.
This study concerned microstructural study of the oxidation products formed on the Co-9Al-9W (at.%) alloy during isothermal oxidation at different temperatures. Therefore, the alloy was prepared via vacuum induction melting (VIM) and casting to a graphite mold. The alloy was subjected to a two-step heat treatment. In the first step, the alloy was are annealed at 1250 °C for 16 h in a tubular furnace and are then water quenched. Afterwards, the ingot is annealed at 900 °C for 100 h.
The oxidation tests were carried out on cylindrical samples ,which were ground, polished and degreased. The oxidation oxide scale formation of the alloy was examined under isothermal conditions in the range 500-1000 °C. The oxidation time was 100 h. The morphology of oxides was examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and their composition was analyzed energy dispersive spectroscopy (EDS). The structures of scales formed at different temperatures were compared.
ACKNOWLEDGEMENTS: This work is financed from the budgetary funds for science for the years 2018-2022, as a research project within the Diamond Grant programme (0069/DIA/2018/47).

In this article, the non-destructive testing of Alnico alloys was carried out by various methods. Paper provides and researches about non-destructive testing (NDT) methods. The research was divided into surface and volumetric test material. The paper covers the review on the capabilities of NDT applications such as Visual Testing (VT), Penetrate Testing (PT), Ultrasonic Testing (UT), Radiographic Testing (RT) with respect to advantages and disadvantages of these methods. ACKNOWLEDGEMENTS: The research reported herein was supported by a grant from the National Centre for Research and Development. Program: Lider XI, grant title: "Improvements in the technology of machining the surfaces of spherical rings of magneto mirrors through the use of electro-erosion machining (EDM)", contract number: LIDER/59/0246/L-11/19/NCBR/2020.

During the operation of fusion devices, the plasma facing components are exposed to high thermal loads from the plasma resulting in mechanical stress formation, as well as to electromagnetic forces and severe particle fluxes. Materials used for this application have to sustain demanding operational conditions. Tungsten represents the material suitable for this application for its high melting point, high strength at elevated temperatures along with good thermal conductivity and high resistance to sputtering. High strength performance of the material is coupled with low ductility. Ductility and thermal conductivity of tungsten can be increased by introducing of copper. Therefore, tungsten and tungsten-copper composite have been studied for their mechanical performance. Samples from both materials were subjected to tensile test at high temperatures in the range from 300 to 600 °C. Elastic modulus along with yield and ultimate tensile strength were evaluated. Scanning electron microscopy was adopted to identify the character of the fracture mode. Typically, the tensile strength decreases as the testing temperature increases for both materials. Addition of copper resulted in significant increase in maximum elongation but also to the loss of strength when compared to pure tungsten. Temperature related mechanical performance of the materials is discussed with respect to fracture morphology of the tested specimens.

The use of salt mixtures properties is considered in many future technologies, such as energy storage or medium for nuclear reactors. The key question is to choose a suitable construction material for these devices operating at high temperatures in a corrosive environment.
Nickel alloys show high corrosion resistance at high exposure temperatures, and literary sources also describe resistance in the environment of fluoride salts. This work verified the corrosion behavior of two nickel alloys in molten chloride salts. Nickel-based superalloys Hastelloy C22 and MoNiCr were tested in a mixture of chloride salts LiCl - KCl (58,2 - 41,8 wt. %). Alloys samples were heated in salt melts for 500 h at 440 ° C in an inert atmosphere of Argon. After removal, they were analyzed gravimetrically, the composition of the surface layers by the XPS and cross-section of samples using SEM.

The paper deals with the possibility of obtaining zinc and iron from waste galvanic sludge, which arises during galvanic plating. Galvanic sludges, which contain significant amounts of heavy metals, form waste suitable for hydrometallurgical recycling. This method has already been proven as a suitable way of treating this type of industrial waste. The aim of the experiments is to obtain zinc and iron by leaching several types of waste samples in different acids and hydroxide, at selected temperatures and time intervals. The leaching process will be followed by electrolysis of the leachate and recovery of the product as a secondary raw material. The practical part also includes chemical and material analyzes of leaching products.

Eutectic high-entropy alloys have become a significantly studied type of material due to their combination of strength and ductility. However, previous research has focused primarily on manufacture, solidification behaviour and mechanical properties. Only a small part of the research has been devoted to welding. This paper focused on evaluating the weldability of eutectic high-entropy alloy AlCoCrFeNi2.1 in the as-cast state without further heat treatment. The electron beam welding process was performed twice at the same parameters, except for the beam current. Properties such as the depth of the remelted layer, the formation of the heat-affected zone, and the presence of undesirable defects in the welded joints were observed using light and electron microscopy. At the same time, material properties in the form of microstructural stability, chemical composition, and hardness of the welded joints were evaluated.

Titanium and titanium alloys have been widely used in medicine as implant materials for the last 50 years. The reason for this could be found in a unique combination of biocompatibility and strength of these alloys. The main advantage of titanium is the ability to bind to bone and grow into the implant. Due to the high cost of production, titanium is not used in large quantities, and therefore research are focused on finding new, more economical alloys. For these reasons, the aim of this paper is to analyze the effect of powder metallurgy process parameters in the production of titanium alloy containing 20% zirconium. Starting elemental powders were a ball milled and then compacted using the hydraulic press. Sintering process was performed under the different values of time and temperature. Starting powders were characterized using the scanning electron microscope. Porosity was analyzed using the light microscope. It was found that it could be decreased by increase in sintering temperature. Hardness of polished sintered samples was determined by Vickers method. Results showed that higher hardness values were obtained in samples sintered at higher temperature. Finally, results show that titanium-zirconium alloy produced by this route of powder metallurgy could be potentially used in a biomedicine.

This paper deals with approximate physical modelling of aluminium melt degassing, performed under low-pressure die casting conditions of aluminium castings. The modelling took place on an aquatic physical model on a 1: 1 scale to the operating conditions, constructed in the laboratories of ITB in ČB. Tested parameters were defined based on operating conditions (rotation speed and inert gas flow). Various combinations of these parameters created 20 tested variants, including the current set of parameters used in operating conditions. The effects of the tested parameters were determined using the results of measurement. Increasing the rotation speed and the inert gas flow accelerates gas removal from the model liquid. It will be possible to further use this knowledge in refining technology optimization in the low-pressure aluminium die casting.

The AlSi9Cu3 alloy, conventionally produced by High-Pressure Die Casting (HPDC), is extensively used in the automotive industry for its high specific strength, good heat and electric conductivity. There is currently an effort to produce this alloy using selective laser melting technology (SLM) due to design possibilities such as producing geometrically complex and lightweight products. However, the performance of SLMed parts is highly dependent on its process parameters. The main aim of this research is to optimize the SLM process parameters of the AlSi9Cu3 alloy to achieve high mechanical performance. The tested process parameters were laser speed and hatch distance in the range of 1200-1500 mm · s⁻¹ and 120-170 µm, respectively. The process parameters selection was performed based on a low porosity level. According to our study, the suitable combination of process parameters is laser power of 350 W, layer thickness of 50 µm, scanning speed of 1400 mm · s⁻¹ and hatch distance of 120 µm. Mechanical properties of SLM samples were compared with cast alloy according to the European Standard (EN 1706:2010). In this paper, the AlSi9Cu3 alloy produced by the SLM process outperformed the mechanical performance of the conventionally cast alloy in 0.2% proof stress (271 ± 1.74 MPa compared to 160 MPa), ultimate tensile strength (494 ± 2.56 MPa compared to 220 MPa), and elongation at break (5.6 ± 0.15 % compared to 1.5 %).

Additive manufacturing or 3D printing is a process of making three dimensional solid objects from a digital file. The creation of a 3D printed object is achieved using additive processes. In an additive process an object is created by laying down successive layers of material until the object is created. In this study laser powder bed fusion (LPBF) was used to process AlSiMg10 alloy. The principle of the method is selectively melting the layers of the metal powder. The energy for melting is obtained by the laser. The process parameters have a crucial influence on the microstructure and mechanical properties of the final product. With understanding of an influence of the basic parameters, we can affect the final mechanical properties. We have found out that the materials with large reflectivity and high thermal conductivity represent an enormous challenge for the mentioned technology. A large part of porosity, cracks, and microstructure non-homogeneity are the main flaws of the products made with the SLM procedure. By setting the right process parameters we can ease or even prevent them. The main goal of the experimental research was to find the most optimal process parameters for producing a batch of samples with the flawless microstructure and the best mechanical properties.