Seznam abstraktů 2024: POSTEROVÁ SEKCE E

More and more attention is being paid to the issues of wastewater treatment of metallurgical and related industries from heavy metal compounds. As part of the study, an assessment of the effect of the addition of surfactants or flocculants on the effectiveness of electroflotation extraction of metals from aqueous media was carried out. It has been established that the addition of flocculants (cationic/anionic/nonionic) can increase the purification efficiency by 1-3% for all systems under study, regardless of the anionic composition of the water being treated. The addition of cationic and anionic surfactants does not have a significant effect on the purification process, while the addition of a nonionic surfactant significantly inhibits the flotation process.

After decreasing the dimensions of objects down to micro and nanoscales, they can exhibit strengths far exceeding those of their macroscopic counterparts. Very high compression strength was reported in various types of metallic nanoparticles. A critical aspect of studying these nanoparticles involves identifying the types of dislocations present. Such identification is crucial in comprehending the underlying mechanisms of their motion and how these particles deform under various conditions. Gas aggregation sources enable the production of crystalline metallic nanoparticles with exceptional purity, where the dimensions are controlled by the preparation conditions. The ability to scale dimensions holds the promise of enhancing mechanical strength and makes the nanoparticles valuable candidates for their potential application in various fields. Titanium nanoparticles were prepared by a DC magnetron sputtering. The structural analysis through selected area electron diffraction confirmed the formation of a hexagonal crystal structure of titanium. The dislocations formed in such prepared nanoparticles were examined by high-resolution transmission electron microscopy.

Corrosion and material selection are critical challenges in the practical design and operation of power plants, chemical plants, pipeline transportation systems, and wells. All of these are components of the systems used to capture and store carbon dioxide (CCS). To guarantee compatibility between the working medium and the structural material, it is necessary to determine which materials are most appropriate. These materials mostly comprise steels or specific nickel-based alloys. We selected Inconel 738 for our investigation. The corrosion coupons of Inconel 738 were exposed to impure carbon dioxide in the High-Temperature Furnace (HTF) at 750 °C and 900 °C for 250, 500 and 1000 hours. The specimen surface, corrosion layer thickness and composition were evaluated by Scanning Electron Microscope (SEM) with Energy Dispersive Spectroscopy (EDS). Glow Discharge Optical Emission Spectrometry (GD-OES) and gravimetric methods were also used to evaluate the materials. All the specimens were covered with a uniform protective oxide layer, growing with exposure time. The layer contained mainly Cr, O2 and a minor amount of Ti. At a temperature of 900 °C, the specimen's weight and corrosion layer thickness increased significantly. These measurements yield an evaluation of the quality of the tested materials, as well as an assessment of their corrosion resistance.

The toxicity of lead with respect to human health and the environment lead to its replacement in solders. Lead-free Sn-Ag-Cu (SAC) solders with good reliability, excellent creep resistance, and thermal fatigue characteristics are the most promising alternative [1, 2]. The aim of this work is to investigate the influence of Ga addition (1, 2, 4 and 6 mass %) on evolution of the microstructure of the SAC305/Cu solder joints. A solder joint consisting of solder applied to a copper sheet was investigated by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The growth of intermetallic phases was observed at the interface between both solder and copper. Finally, experimental results were compared to thermodynamic calculations of the Sn-Ag-Cu-Ga system.

ACKNOWLEDGMENTS
This work was supported by the Grant Agency VEGA (1/0389/22) and Slovak Research and Development Agency (APVV-20-0124).

REFERENCES
[1] Kim K, Huh S, Suganuma K. Effects of fourth alloying additive on microstructures and tensile properties of Sn-Ag-Cu alloy and joints with Cu. Microelectron Reliab. 2003; https://doi.org/10.1016/S0026-2714(02)00239-1
[2] Zeng G, Xue S, Zhang L, Gao L, Dai W, Luo J. A review on the interfacial intermetallic compounds between Sn-Ag-Cu based solders and substrates. J Mater Sci: Mater Electron. 2010; https://doi.org/10.1007/s10854-010-0086-y

The Sn-rich Pb-Sn alloys were historically used for numerous products, from organ pipes to jewelries. Later industrial applications include food cans or a vast majority of electrical-engineering products containing Pb-Sn solders. While recently banned in favor of lead-free solders, the Pb-Sn alloys are still important not only when studying historical artifacts or handling millions of tons of electrical-engineering waste, but also when developing new Sn-containing materials. In our theoretical study, we employed quantum-mechanical calculations to determine the thermodynamic and dynamical stability of both elemental tin and selected Pb-Sn alloys. In particular, phonons and vibrational contributions to the free energy were determined for the cubic diamond-structure phase as well as body-centered tetragonal and hexagonal phases within the harmonic approximation.
Our results clearly indicate an important role played by phonons in the stability of studied phases. In particular, the contribution of the free lattice vibration energy causes a shift in the stability, i.e. in the energy order between the alpha, beta and gamma tin at higher temperatures. At T = 0 K, the alpha phase is the most stable structure of pure tin, the second most stable structure is the gamma phase and the least stable is the beta tin. This order changes at temperature T = 115 K when the beta tin becomes more stable than the gamma tin and, at higher temperatures, it becomes the most stable form of tin. Very similar trends were observed in the temperature dependence of the free energy contribution for Pb-Sn structures with 9.375 atomic percent of lead. The T = 0 K order of stability was the same as for pure tin, but the termodynamic competition of the hexagonal gamma structure and the beta Pb-Sn structure at elevated temperatures sensitively depends on vibrational degrees of freedom.
Financial support from the Czech Science Foundation, project "Causes and mechanisms of degradation of tin-based materials with a low content of alloying elements" No. 22-05801S, is gratefully acknowledged. Computational resources were provided by the e-INFRA CZ project (ID:90254), supported by the Ministry of Education, Youth and Sports of the Czech Republic. These resources were utilized through IT4Innovations National Supercomputing Center, MetaCentrum as well as CERIT Scientific Cloud.

Ni-base superalloy is known for its excellent performance in high-temperature applications such as jet engines. In this study, we want to improve the 0.2% proof stress of Ni-base superalloy beyond the level of the simpler (Isothermal heat treatment) IHT done by humans. Our approach is to use machine-learning methods to optimize a more flexible (non-IHT) schedule. We present a new method that leverages the performance of Monte Carlo tree search (MCTS) by using ensemble concept for multiple trees. MCTS is a machine-learning method that has demonstrated efficiency and scalability in several applications in materials inverse design; however, a single Monte Carlo tree can face initial biases that affects the performance. In this ensemble, multiple trees search different areas of the candidate space simultaneously. Each tree will communicate its data with the other trees via a neural network that is trained on data from all trees and then, provides expansion guidance to each tree. This approach can accelerate the search for optimal heat treatment schedule from a vast number of potential candidates. The proposed method can be applied autonomously on several materials inverse design problems.

The research deals with the evaluation of internal quality of zinc castings in terms of porosity. The castings were produced by high-pressure die casting from ZP0410 alloy, which is an alloy of zinc with addition of aluminium and copper. For the evaluation, a computed tomography was used on a Werth Tomoscope XL, which allows for a non-destructive analysis of the internal structure of the casting and the creation of a 3D model of the porosity distribution inside of the casting. It also allows the number of cavities and the proportion of porosity in the casting volume to be determined. Castings from a two-cavity mould were evaluated. The mould is made of H11 steel. The investigation of the internal structure was carried out on castings from both cavities of the mould during its service life. Three samples of castings from each cavity were taken from a new mould and then after approximately every 100,000 shots up to 700,000 shots. Evaluation by computed tomography revealed that microporosity was present inside the whole casting. Larger cavities are generally found around the central hole in the area of the highest wall thickness. The number of cavities was different for the two positions of the castings up to 400,000 shots, with the number increasing for K3 castings and varying between increasing and decreasing for K4 castings. After reaching 400,000 shots the number of cavities in castings matched and a decrease to approximately 2,000 occurred. The volume of porosity at 700,000 shots was 0.4%.

Among Sn-Ag-Cu (SAC) lead-free solders, SAC305 (96.5 wt.% Sn, 3.0 wt.% Ag, and 0.5 wt.% Cu) and SAC387 (95.5 wt.% Sn, 3.8 wt.% Ag, and 0.7 wt.% Cu) are the most preferred candidates used in industry as a replacement for Sn-Pb solders [1]. Additional alloying elements, such as Bi, In, Ga, Ni, can lower the melting temperature and optimize the thickness and morphology of the intermetallic compound (IMC) layer [2-4]. However, there is a tendency to reduce the Ag content to reduce the overall cost of solders. Therefore, the aim of this work is to study the SAC108 (98.2 wt.% Sn, 1.0 wt.% Ag, and 0.8 wt.% Cu) lead-free solder enriched with various Ga content and its effect on the microstructure and hardness. In the investigation, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Vickers hardness testing were used. The phase composition of the individual Ga-enriched SAC108 solders is discussed and compared to pure SAC108. The effect of Ga addition on hardness is evaluated. The influence of lower Ag content is also discussed, based on a comparison with previously studied SAC305 solders.

Acknowledgments
This work was supported by the Grant Agency VEGA (1/0389/22) and Slovak Research and Development Agency (APVV-20-0124).

References
[1] Zhou D, Haseeb ASMA, Andriyana A, Mechanical performance of advanced multicomponent lead-free solder alloy under thermal aging. Mater Today Commun. 2022; https://doi.org/10.1016/j.mtcomm.2022.104430
[2] Sivakumar P, O’Donnell K, Cho J. Effects of bismuth and nickel on the microstructure evolution of Sn-Ag-Cu (SAC)-based solders. Mater. Today Commun. 2021; https://doi.org/10.1016/j.mtcomm.2020.101787
[3] Kim KS, Huh SH, Suganuma K. Effects of fourth alloying additive on microstructures and tensile properties of Sn-Ag-Cu alloy and joints with Cu. Microelectron. Reliab. 2003, https://doi.org/10.1016/S0026-2714(02)00239-1
[4] Zhao J, Qi L, Wang X, Wang L. Influence of Bi on microstructures evolution and mechanical properties in Sn-Ag-Cu lead-free solder. J. Alloys Compd. 2004; https://doi.org/10.1016/j.jallcom.2003.12.005

In the present research the microstructure and mechanical properties of TIG welded AA6061 Al alloy utilizing TiO2 containing filler metal were investigated via microscopic observation, microhardness measurement and tensile test evaluation. For this purpose, spray method was used to make various TiO2 containing filler metal with 0.5 and 1.5 wt.% TiO2 nano particles. The size of the TiO2 nanoparticles were 50 nm in average. The optical microscopic results showed that increase of TiO2 nanoparticles in filler metal have significant effect on refinement of FZ microstructure. The mean grain size of TiO2 free and containing 1.5 %wt. TiO2 samples were 65 µm and 38 µm respectively. The microhardness test were conducted to demonstrate the effect of TiO2 on the hardness of different zones of welded specimens. The results showed that increase in TiO2 nanoparticle in FZ results to higher FZ hardness due to grain refinement and composite effect of TiO2 nanoparticles. The HAZ softening also were observed in all samples. The ultimate tensile strength of FZ was measured utilizing tensile test examination. The results showed that with increasing TiO2 in the FZ, the tensile strength of this region increased. The tensile strength of TiO2 free and containing 0.5 and 1.5 wt.% of TiO2 were 185, 200 and 215 MPa respectively.

Quantum computing is newly emerging information-processing technology which is foreseen to be exponentially faster than classical supercomputers. Current quantum processors are nevertheless very limited in their availability and performance and many important software tools for them do not exist yet. Therefore, various systems are studied by simulating the run of quantum computers. Building upon our previous experience with quantum computing of small molecular systems (see I. Miháliková et al., Molecules 27 (2022) 597, and I. Miháliková et al., Nanomaterials 2022, 12, 243), we have recently focused on computing electronic structure of periodic crystalline materials. Being inspired by the work of Cerasoli et al. (Phys. Chem. Chem. Phys., 2020, 22, 21816), we have used hybrid variational quantum deflation (VQD) algorithm, which combined classical and quantum information processing. Employing tight-binding type of crystal description, we present our results for crystalline diamond-structure tin. In particular, we focus on the states along the lowest occupied band within the electronic structure of Sn and compare the results with values obtained by classical means. While we demonstrate an excellence agreement between classical and quantum-computed results in most of our calculations, we further critically check the sensitivity of our results with respect to computational set-up in our quantum-computing study. A financial support received under the Project No. 22-05801S from the Czech Science Foundation is gratefully acknowledged. We also gratefully acknowledge the financial support from the Czech Academy of Sciences (the Praemium Academiae of M.F.). Computational resources were provided by the e-INFRA CZ project (ID:90254), supported by the Ministry of Education, Youth and Sports of the Czech Republic. These resources were utilized through IT4Innovations National Supercomputing Center, MetaCentrum as well as CERIT Scientific Cloud.

Titanium and titanium alloys offer a unique combination of properties (e.g. high specific strength, biocompatibility and corrosion resistance). The production volumes of titanium are lower compared to other metals, despite its excellent properties and relatively high mineral resources. It is all caused by the costly and ineffective production method, so-called Kroll process. A reduction in costs could lead to an increase in the use of titanium and its alloys. Recycling of titanium scrap is a potential solution. However, the recycling process might be problematic due to the contamination of scrap by gasses, cutting fluids, machining debris, oxide layer caused by titanium’s high reactivity with oxygen etc. As a result, most of titanium scrap being used for production of a ferrotitanium (deoxidising element for steel) rather than being recycled into titanium alloys.
The suitable recycling method, which would allow to use titanium scrap for manufacturing of materials comparable to the primary alloys, could represent significant change for the titanium market.
The aim of this work is to evaluate the recycling process of Ti-6Al-4V alloy using the plasma arc melting method and subsequently to assess the possibilities for its use in additive manufacturing. The purity, microstructure and mechanical properties of recycled alloy were analysed. The powder obtained from atomizing the same recycled alloy has been evaluated (distribution, morphology and chemical composition) and possibilities of processing this powder by two 3D printing methods, laser powder bed fusion (LPBF) and direct energy deposition (DED), were investigated.

This work deals with the increase in mechanical and utility properties of diamond grinding wheel with controlled porosity prepared by the sintering along the diamond grain boundary using binder material based on Cu-Sn-Ti alloy with subsequent hot isostatic pressing (HIP). The structure of diamond grinding wheel contained after sintering a large proportion of open porosity (35 to 39 %), which ensures a very good supply of coolant to the grinding point and at the same time removes the ground material from the grinding point. The effect of HIP on the structural characteristics, phase and chemical composition by SEM/EDX and XRD were studied in detail. The samples before and after HIP were subjected to the three-point bending test and the Brinell hardness test, which are the most important from the point of view of potential applications. The process of hot isostatic pressing led to the densification of necks formed between diamonds grains and to significant increase in the bending strength. The titanium-rich phases formed a shell around the diamond grains, improving their anchoring in the metal matrix. The grinding wheel showed very good utility properties that allow it to be used for long-term grinding with low resistance while maintaining shape stability during grinding.

Gas aggregation sources (GAS) based on physical vapor deposition are nowadays commonly used for the preparation of metallic nanoparticles or composite nanostructures containing metals, oxides, nitrides, polymers, etc. The most common GAS configuration device for the preparation of core-shell Ni-Ti nanoparticles consists of the primary aggregating source producing the Ni core followed by a second chamber with a Ti target overcoating the core by a shell. The size distribution of core nanoparticles and the thickness and homogeneity of the shell depend on the geometry of the deposition chambers, pressures of working gas, and the power (current, voltage) on both magnetrons. Unfortunately, the power on the Ti magnetron could significantly modify not only the parameters of the coated layer but also the size of the Ni core. The influence of the Ti magnetron current on the final size and homogeneity of complex core-shell particles was studied by high-resolution transmission electron microscopy, scanning (transmission) electron microscopy, and energy-dispersive X-ray spectroscopy. A threshold current value leading to significant morphological changes of nanoparticles was identified.

The paper characterizes selected lead-based wastes occurring in the metalworking industry, such as wire manufacturers using lead baths in the heat treatment process. Attention is focused on the possibility of using the proportion of lead in direct metal form, which can occur in certain types of waste. For waste, the content of selected metals and the form of their occurrence was determined. For waste with lead in metallic form, pyrometallurgical tests were performed to obtain the proportion of lead from industrial waste. Subsequently, the purity of the obtained product was determined, which is related to its use directly back into the given technological procedure. It was found, that with remelting of the given type of waste at relatively low temperatures it is possible to obtain an interesting proportion of pure lead. The secondary lead has sufficient purity and can be reused and thus support the sustainability of the process. Conversely, certain parts of waste contain such a small amount of metals, including lead, that it would be possible to use them in a different way than to pass them into the system as waste containing heavy metals. These wastes must then be recycled in specialized plants. Companies are currently reassessing their established procedures for dealing with production waste and looking for new possibilities for using waste directly in their plants. Recovering the share of lead in the process and the subsequent possibility of reassessment of the dangerousness of certain shares of industrial waste is a way to improve the company's position in waste management and the use of raw materials.

Non-ferrous metal (such us Zn, Pd, Pt, Cu) complexes with different organic ligands are newly materials of huge interest for biomedical applications, these including antibacterials, antifungals, anticancer, etc. The main goal of this work was to obtain, characterize and to establish the biological proprieties of newly materials based on non-ferrous Zn2+ metal with different quinoline-sulfonamide organic ligands. The newly non-ferrous Zn2+ were obtained by complexation of quinoline-sulfonamide organic ligands with zinc chloride or zinc acetate. The structure of the obtained materials were determined by using different spectroscopic methods: FT-IR, NMR and X-ray diffraction on single crystal. The non-ferrous Zn2+ materials were tested for their antibacterial (against gram positive bacteria Staphylococcus aureus ATCC25923 and the gram negative bacteria Escherichia coli ATCC25922) and antifungal (Candida albicans ATCC10231) properties. The obtained results indicate a promising antibacterial activity for some compounds, with a diameters of inhibition zones in the range of 20-30 mm. The antifungal tests were negative. ACKNOWLEDGEMENTS to Romanian Ministry of Research, Innovation and Digitization, Contract no.11PFE/30.12.2021.

During the last decades, non-ferrous materials based on palladium metal and organic ligands are of considerable interest for biomedical applications, especially as potential drugs for treatment of cancer and microbial diseases. The purpose of this work was to obtain materials based on Pd2+ metal with different quinoline-sulfonamide organic ligands and to test their antimicrobial properties. The non-ferrous Pd2+ materials were synthesized from palladium acetate and different quinoline-sulfonamide organic ligands. The obtained materials were characterized by X-ray diffraction, FT-IR and NMR spectroscopic methods. Then the newly non-ferrous Pd2+ materials were tested for their biomedical applications: antibacterial and antifungal. For antibacterial tests were used the gram positive bacteria Staphylococcus aureus ATCC25923 and the gram negative bacteria Escherichia coli ATCC25922 while for antifungal tests was used the fungus Candida albicans ATCC10231. The results reveal a good antibacterial and antifungal activity, some compounds having with a diameters of inhibition zones in the range of 20-30 mm and a MIC in the micromolar range. ACKNOWLEDGEMENTS to Romanian Ministry of Research, Innovation and Digitization, Contract no.11PFE/30.12.2021.

Plasma transfer arc surfacing is very perspective technology, which is currently used to create layers with special properties such as corrosion resistance, wear resistance or resistance against high temperatures. In case of Nickel based alloys, one of the perspective way how to increase wear resistance of Nickel based coatings is addition of hard ceramic particles using plasma transfer arc surfacing technology in to the structure. This study deals with creating and characterization of metal matrix composite (MMC) based on Nickel-alloy 625 type with B4C. MMC with B4C was created by co-feeding Nibasit 625 - P/LFe® and B4C powder into a melting pool. The two powders were mixed together in two ratios. B4C particles have been dispersed in deposited coatings, they have partially dissolved in Ni-based matrix and formed different microstructural formations such as carbides and borides. Dissolution of B4C particles ensures good cohesion with matrix. Coatings are well metallurgically connected to the substrate - AISI 304 corrosion resistant steel. Coatings were examined in terms of microstructure and chemical composition. In macro-view perspective Vickers hardness has been measured and abrasion resistance test using dry sand/rubber wheel according to ASTM G65 standard has been performed.

Slags formed during metallurgical extraction of zinc and lead have varied chemical and mineral composition and contain considerable amounts of various chemical elements, among them toxic metals. contain significant amounts of metals and semi-metals, the predominant ones being: Si, Al, Ca, Ma, Zn, Pb. Among the slags of Zn-Pb metallurgy, refining slags can be distinguished, characterized by much higher contents of Zn, Pb and Cu, with significantly lower concentrations of Si, Al, Ca, Mg.
The mineral composition of Zn-Pb metallurgical slags is dominated by multiphase crystalline conglomerates formed by high-temperature processes. Typical mineral constituents in these slags are: Zn and Fe oxides and Fe hydroxides, Zn, Pb, Fe and Cu sulphides, Pb sulphates and hydrated Zn, Ca, Cu sulphates, Zn silicates, silicates of the olivine group, melilites (Ca,Na)2(Al,Mg)[(Si,Al)2O7], Pb and Zn carbonates, spinels and multicomponent metal alloys of Pb, Zn, Cu, Fe, As, Sb.
Due to these properties, slags from Zn-Pb metallurgy can constitute a source of environmental pollution on the one hand and an anthropogenic deposit on the other.
The paper presents the results of research on the chemical and phase composition of products and waste generated during the pyrometallurgical processing of refining slags from the Zn-Pb metallurgy.
It was found that there was a significant share of metallic lead in the product - sinter, with a very high share of silicate and oxide phases in the waste.
The chemical and phase composition of the tested materials proves the correct course of the pyrometallurgical processing of slags, and the high lead yield (>70%) indicates the correct selection of its recovery technology, which is the basis for continuing research on the processing of refining slags using the pyrometallurgical method.
The processing of metallurgical slags is an extremely important issue as, in addition to the economic benefits, it results in the significant neutralization of slags as a potential source of environmental pollution.

The non-destructive method internal friction (IF) allows to set the spectrum of structural defects on the analysis of positions IF maximums Q-1M, on duration of relaxation time τ and on their deposit in attenuation of elastic vibrations. The criterion of structural relaxation is formed: anelastic structural relaxation can be caused by the structure defects, the system of symmetry of which below type symmetry of crystal. It does not determine the effect value of relaxation. The temperature dependence of internal friction Q-1 and elastic modulus Е (“indicatory surface of anelastic-elastic body”) of Ag0.8Zn0.2 alloy was studied. After electron irradiation sharp exponential growth of internal friction background Q-10 was observed at temperatures T > 610 K. The effect of radiation exposure on the temperature dependence of internal friction Q-1 and elastic modulus Е of Ag0.8Zn0.2 alloy, which is ordered, was studied. The temperature intervals of the formation and rearrangement of the short-range order are revealed. The influence of electron irradiation and thermomechanical treatment on the short-range ordering processes of AgZn solid solutions was studied. After electron irradiation the temperature dependence of internal friction Q-1 and elastic modulus Е (“indicatory surface of anelastic-elastic body”) of Ag0.8Zn0.2 alloy revealed internal friction maximum Q-1М1 at the temperature TМ1 ≈ 560 K. The strengthening of alloys is related to co-operating of dislocations with point defects.

Drilling has an essential place in machining processes. Therefore, optimizing the parameter levels used in drilling is valuable regarding process quality. The optimization process can be carried out to minimize the thrust force. An experimental study was conducted to determine cutting parameters' effects on thrust force. Optimizing cutting force not only saves energy but also reduces tool wear. This study optimized cutting parameter levels based on the forces that occur during drilling in aluminum AA5083 H111 alloy material, frequently used in the maritime and aerospace industry. Cutting speed, feed rate, and cooling type were selected as cutting parameters with three levels. These are cutting speeds of 80, 100, and 120 m/min, feed per tooth 0.06, 0.09, and 0.12 mm/tooth, and cooling types are dry, air cooling, and liquid cooling. The optimization process was carried out with the response surface method. The effects of the parameters on the cutting force were found by analysis of variance.

During the operation of fusion devices, plasma facing components (PFCs) are subjected to high heat loads. These result in mechanical stresses and various forms of degradation and microstructural changes in the material volume. In order to assess the viability of the PFC candidate materials, the samples were subjected to high heat flux tests simulating heat load pulses caused by plasma instabilities. The presented study includes a thermal model developed in ANSYS Fluent software to simulate the temperature profile at different depths of the sample and its evolution during the tests. High heat flux testing was performed using an electron beam facility. Short pulses (~1 s) of up to 40 MW/m2 power density were applied to the top surface of 10 mm wide cylindrical samples. Homogeneous heat flux distribution over this circular area was achieved by scanning the electron beam in a dense pattern with >104 points. The temperature evolution during exposure was monitored using a thermocouple inserted into the sample along with the surface temperature measured by a pyrometer. Scanning electron microscopy was used to document surface degradation. The loaded surface of the materials typically exhibited the formation of slip bands along with the formation of a dense net of intergranular cracks, while microstructural changes in terms of recrystallization of the material were observed in the bulk material. Based on the tests performed, where the measured temperature profile during the experiment qualitatively corresponds to the ANSYS simulation, the developed thermal model was verified.

Humankind’s ability to explore the solar system has so far been limited by the small amounts of hardware and consumables that can be carried by spacecraft from Earth. To enable longer, more autonomous and more sustainable missions to the Moon, Mars and beyond, the ability to efficiently use the resources available locally (e.g. minerals, volatiles) is crucial. This approach is known as In-Situ Resources Utilization (ISRU).

One of the promising techniques being investigated is the molten salt electrolysis of lunar soils (i.e. lunar regolith). By electrochemically reducing the oxides contained in this mineral feedstock, both gaseous oxygen and metallic solids are produced. This process has been demonstrated at a lab scale using lunar soil simulants by Lomax et al. [1] and Meurisse et al. [2].

We present characterization results of the solid products yielded by this process, a heterogeneous granular compound containing mainly Mg, Al, Si, Ca, Ti & Fe. Bulk and local compositions are evaluated by SEM-EDX and XRD. Residual oxygen content is evaluated by inert gas fusion. In addition, the thermal behaviour of the compound is studied by DSC/TG, to assess the viability of melting processes for further refinement of the material into usable alloys.

[1] Lomax, B.A., Conti, M., Khan, N., Bennett, N.S., Ganin, A.Y., Symes, M.D., 2020. Proving the viability of an electrochemical process for the simultaneous extraction of oxygen and production of metal alloys from lunar regolith. Planetary and Space Science, 180, 104748. https://doi.org/10.1016/j.pss.2019.104748

[2] Meurisse, A., Lomax, B.A., et al., 2022. Lower temperature electrochemical reduction of lunar regolith simulants in molten salts. Planetary and Space Science, 211, 105408. https://doi.org/10.1016/j.pss.2021.105408

The structures of the Ag-Cu metastable metal-matrix composites (m-MMCs) that were prepared by spark plasma sintering of Cu@Ag core-shell powders were studied in this work. Powders of two compositions, 51:49 and 80:20 in mass ratio, were used for producing the m-MMCs. The structures of the metastable metal-matrix composites were investigated by light and electron microscopy in as-prepared and deformed samples. The m-MMCs were found to consist of spherical Cu particulates and Ag matrix in an as-prepared state. Furthermore, the m-MMCs containing Cu and Ag in the mass ratio 51:49 exhibited predominantly spherical particulates in the Ag matrix, while mainly clusters of Cu particulates existed in that with the ratio 80:20. The deformed samples exhibited the prolongation of the spherical particulates in the direction of the tensile deformation while compression led to their prolongation perpendicularly to it. As expected, the change of the particulate shape during plastic deformation of the Ag-Cu m-MMCs depends on the level and type of the plastic deformation. It can be concluded that the spark plasma sintering technique is suitable for producing the m-MMCs containing reinforcement of pure Cu in a pure Ag matrix, where the diffusion processes between the core and shell of the default powder are suppressed.

ACKNOWLEDGEMENT: This work was financially supported by the Czech Science Foundation under the grant No. 23-05139S. One of the authors (AS) acknowledges the grant of the Czech Academy of Sciences under No. L100102403.

The work deals with the study of progressive composite materials based on a matrix of NiAl and a reinforcing FeSi phase. Typically, these aluminides and silicides are prepared by powder metallurgy techniques - mechanical alloying of both input compounds and subsequent final processing using SPS. In this work, the fabrication is realized through vacuum induction melting and centrifugal casting. The aim of the work will be to obtain materials with similar mechanical properties as tool steels of higher quality. Elemental pure metals with a purity of 2N5 - 3N were used as input materials. Melting crucibles based on Al2O3 were used for melting, which were not provided with any protective coating. Casting was realised in a mold made of isostatically pressed graphite. By this way, the final castings were obtained in the form of a rod with a diameter of 20 mm and a length of 220 mm. In terms of the ratio of the base matrix and the strengthening phase, two experimental alloys were prepared. After the melting and casting process, the prepared alloys were heat treated at 900°C/3h in a protective atmosphere (Ar, 5N). The microstructural characteristics of the prepared alloys were evaluated using the LOM and SEM methods. The chemical composition of the prepared alloys was determined using EDX. The phase composition was tested by powder X-ray diffraction analysis. In the next phase, the mechanical and tribological properties were evaluated.

For a better understanding of the phenomena of phase transition in pure tin, the low-temperature phase transformations were investigated by X-ray diffraction and Mössbauer spectroscopy in the temperature range 180 - 300 K. The phase analysis was focused on the transition of the beta-tin (bct) phase to the alpha-tin (fcc) phase. Avrami equation was applied to the data for the time dependences of this transition for the constant temperatures, and its parameters were used for the Arrhenius plot. Results derived from data from Mössbauer spectroscopy show a maximum transformation rate at ~200 K. Similarly, XRD data shows the maximum at ~210 K. The difference can be ascribed to changes in the cooling conditions in cryostats in the Mössbauer spectrometer and XRD equipment.

Aluminum alloy rims can be produced using the following methods: forging, gravity casting and low pressure casting. Regardless of the advantages and disadvantages of each of these technologies, the most frequently used method of producing rims from Al-Si alloys is low-pressure casting (up to 0.2 MPa). This process ensures that products of good quality are obtained, with the required functional properties and shapes imposed by the customer, at a comparably low production cost. Casting rims under low pressure can be conventionally divided into main and auxiliary processes. The former concern the place where the rims are made: melting shop (foundry), heat and mechanical treatment, diamond cutting, paint shop. Auxiliary processes include inter-operational inspections, visual assessment of the finished rim, preparation of casting tools, raw materials management and in-plant logistics.
The article was created thanks to the courtesy of the authorities of Superior Industries Production Poland sp. z o. o.