Seznam abstraktů 2025: SEKCE E - NEŽELEZNÉ KOVY A SLITINY

As metal-matrix composites (MMCs), the materials are usually considered, containing soft matrix and hard particulates of various shapes. Accordingly, they can well serve for numerous practical applications. From the viewpoint of understanding detailed mechanisms of deformation, it is also interesting to study MMCs containing not only soft matrix but also the particulates. We refer to the microstructure and plastic deformation of both types of MMCs - Ag-Cu and Ag-W, both produced by spark plasma sintering (SPS) of the Cu@Ag and W@Ag core-shell powders and characterized by spherical particulates. While the deformation of the former one is characterized by simultaneous deformation of Ag matrix and Cu particulates, in the latter MMC only Ag matrix deforms plastically. It is shown that plastic deformation in Ag-Cu MMC is distributed between both structural components non-homogeneously with higher deformation of the particulates. Compression of Ag-W MMC provides an unexpected course of the stress-strain curve due to fracture and densification processes.

The strong magnetic field systems are widely used. in modern fundamental and applied research, as well as in the most advanced industrial processes. These systems generate magnetic fields ranging from 5 to 100 Tesla, which can expose conductors due to extremely high Lorentz forces. Consequently, the conductor materials must exhibit exceptional mechanical strength (with an ultimate tensile strength of at least 600 MPa) and good specific electrical conductivity (IACS ≥ 60%). Traditional conductors such as copper, aluminum, gold, and silver are unable to withstand these large stresses. Therefore, micro-composite materials of conductors have been developed, combining high strength with favorable electrical conductivity. One of the key unresolved challenges in high-field magnetic systems is the development of reliable non-destructive joints and their joining technologies. In practice, the majority of conductors joints are still made using mechanical fastening or soldering methods, which are inherently destructive and often lack long-term reliability. This study investigates resistance welding technology and properties of Cu-Nb 18% micro-composite conductor joints. The research focuses on the selection of upset welding parameters, analysis of the chemical composition and microstructure of the butt joints, evaluation of the mechanical and electrical properties of the butt joints.

Cu-P-Ag alloys are widely used in brazing applications due to their excellent thermal and electrical conductivity. However, optimizing their mechanical properties, particularly ductility, is crucial to improving performance and workability. This study examines the effect of heat treatment on the residual stress, hardness and microstructural evolution of Cu-P-Ag brazing wires. Samples were subjected to various heat treatment conditions, including furnace cooling, air cooling and quenching, followed by microstructural and mechanical characterization. Results indicate that silver precipitation begins around 350°C and becomes more visible at 450°C, contributing to changes in hardness. Residual stress measurements suggest that furnace cooling favors tensile stresses, which may improve ductility, while air and water quenching tend to introduce compressive stresses, which increase hardness. These results highlight the role of heat treatment in achieving a balance between strength and flexibility in Cu-P-Ag alloys, with furnace cooling emerging as the most effective method for improving ductility. This study provides valuable insights into optimizing the mechanical properties of Cu-based brazing wires by heat treatment, with potential benefits for industrial applications.

The influence of thermomechanical processing history on the microstructure and thermomechanical behavior of Ti-3Al-8V-6Cr-4Zr-4Mo titanium alloy was subjected to the analysis in this research. The alloy flow stress curves were elaborated basing on compression tests performed under various temperatures and strain rates. Various criteria of stability and instability of the material flow were taken into account to analyze the material behavior under various thermomechanical conditions. The research shown, that the inhomogeneity of the alloy's microstructure in the initial state is a significant factor affecting the inhomogeneity of deformation. It was also shown, that the processing maps developed using various criteria are an effective tool in predicting flow instability and optimising hot forming parameters. The processing maps clearly showed the set of thermomechanical parameters leading to the formation of adiabatic shear bands and strain localisation during deformation of the investigated alloy, but also enabled identifying optimal conditions for dynamic recrystallisation and material softening. The obtained results may have direct applications in the design of thermomechanical processing of the investigated titanium alloy under industrial conditions.

Titanium alloys are widespread in different industries due to their beneficial mechanical properties, chemical resistance, biological compatibility, and light weight. Especially their high strength-to-weight ratio makes titanium alloys a backbone for the aerospace industry. Today the most commonly used alloy for aerospace components is Ti-6Al-4V.
Critical structural aerospace components are generally forged, heat-treated, and machined to the final contour. During the cooling process, at the end of the heat treatment, residual stresses arise due to temperature gradients in the component and the accompanying visco-plastic effects in the material [1]. These residual stresses can lead to excessive distortion during the final machining process so that the final contour cannot be achieved. Therefore, knowledge of the residual stress field is of utmost importance in order to optimize the ma-chining strategy to minimize distortion.
For this purpose, a finite element approach is used to model the residual stresses during gas-quenching. In order to describe the material behavior, a comprehensive material characteri-zation is performed over a wide temperature range, including cyclic strain and relaxation experiments, for different cooling rates, to calibrate an elasto-viscoplastic material model [2,3,4]. For reliable simulation results, adequate assumptions for the heat transfer coefficient during gas-quenching are indispensable. Therefore, quenching is performed on a dummy part, instrumented by thermocouples; these measurements are then used for determining the heat transfer coefficient by means of inverse optimization.
For experimental validation, the residual stresses are characterized on the dummy part by X-ray diffraction measurements and cut-compliance experiments. Additionally, machining ex-periments are performed and numerically replicated to compare the distortion between ex-periment and simulation.

References
[1] Leitner S, Winter G, Klarner J, Antretter T, Ecker W. Residual stress evolution in low-alloyed steel at three different length scales. Materials 2023; 16:2568. https://doi.org/10.3390/ma16072568
[2] Krobath M, Krobath R, Bernhard C, Ecker W. Elasto-viscoplastic material model of a directly-cast low-carbon steel at high temperatures. Materials 2020; 13:2281. https://doi.org/10.3390/ma13102281
[3] Chaboche, J-L. A review of some plasticity and viscoplasticity constitutive theories. Int. J. Plast. 2008; 24:1642-1693. https://doi.org/10.1016/j.ijplas.2008.03.009
[4] Kaltenbrunner T, Krückl HP, Schnalzger G, Klünsner T, Teppernegg T, Czettl C, Ecker W. Dif-ferences in evolution of temperature, plastic deformation and wear in milling tools when up-milling and down-milling Ti6Al4V. J. Manuf. Process. 2022; 77:75-86. https://doi.org/ 10.1016/j.jmapro.2022.03.010

Among titanium-based alloys, Ti6Al4V is the most widely material used for structural applications due to its exceptional strength-to-weight ratio, high corrosion resistance, and biocompatibility. It has been extensively processed using laser beam powder bed fusion (L-PBF), as this additive manufacturing technique enables the production of near-net-shape components, leading to significant cost savings. However, the processing parameters employed during L-PBF play a critical role in determining the resulting microstructure, defect formation, and mechanical properties. This study investigates the microstructural characteristics and relative density of Ti6Al4V alloy fabricated under varying energy densities. The results demonstrate that defect formation is strongly influenced by the applied energy density, with a significant impact on mechanical properties, particularly ductility. Additionally, higher laser power is shown to reduce the sensitivity of other processing parameters, facilitating the production of high-quality components at increased scanning speeds and reduced processing times. A comprehensive analysis of individual process parameters is provided, including the effects of hot isostatic pressing (HIP) and post-processing heat treatments on microstructural evolution and mechanical performance.

High entropy alloys (HEAs), unlike conventional alloy systems, have attracted growing attention due to their unique combination of structural and functional properties arising from their multi-principal element design. In recent years, Bio-HEAs, composed of elements with proven biocompatibility, have emerged as promising candidates for biomedical applications. In this study, four equiatomic HEAs (TiNbTaZr, TiNbTaZrMo, TiNbTaZrHf, and TiNbTaZrV) were synthesized using vacuum arc melting. The structural characteristics of the HEAs were analyzed by X-ray diffraction (XRD), while their microstructures were examined via scanning electron microscopy (SEM). Elemental distributions within the microstructures were investigated using energy dispersive X-ray spectroscopy (EDS). Mechanical behavior was assessed through Vickers hardness testing, which revealed a clear correlation between alloying elements, structure and hardness. Among the HEAs, TiNbTaZrMo exhibited the highest hardness value of 516.00 ± 2.65 HV, whereas the base alloy, TiNbTaZr, showed a hardness of 323.60 ± 5.18 HV. The additions of V and Hf resulted in hardness values of 410.20 ± 4.27 HV and 316.20 ± 4.66 HV, respectively. XRD analysis indicated the presence of dual BCC phases in the Mo- and V-containing alloys, while a single BCC phase was observed in the base and Hf-containing HEAs. Microstructural analysis revealed two distinct phase regions: Ta-rich and Zr-rich domains. These findings highlight the significant influence of alloying element selection on phase evolution and mechanical performance, demonstrating the potential for tailoring bio-HEAs for specific biomedical applications.

High entropy alloy (HEA) superconductors recently gained attention to researchers because of better chemo-mechanical property in addition to superconducting behaviour. Nb based HEAs were among those who have emerged successful as the superconducting bulks. However, the existing literatures still focuses on deciphering the superconductivity behaviour only based on valence electron count (VEC) or through structural disorderliness [1] different from the traditional superconductors. Traditional superconductors show variations in superconducting behaviour when microstructure is engineered.
This present work reports the novel Nb-Ti-Zr-Pt HEA with different alloy configurations as (Nb, Zr, Pt)67Ti33, Nb67(Ti, Zr, Pt)33 and (Nb, Pt)67(Ti, Zr)33 to understand the superconducting behaviour through a microstructure - functional property correlation approach. The bulk is synthesized through arc melting route. Different heat treatment conditions are utilized to engineer the microstructure, and its effect were analysed on critical temperature, Tc and critical current density, Jc. The microstructure evolution with phase stability were studied using advanced electron microscopy techniques. The functional characteristics were analyzed using magnetic property measuring systems (MPMS). The samples annealed at 1100 °C for 9 hrs are observed to attain relatively better functional behaviour with a high reported Tc of 8.3 K at 5 mT under zero field cooled (ZFC) condition and Jc of 80 kA cm-2 at 4.2 K under self-field condition for (Nb, Zr, Pt)67Ti33 alloy [2]. Possibility of formation of stoichiometric A15 Nb3Pt phase (as confirmed by Scanning and Transmission electron microscopic and X-ray diffraction technique) and magnetic flux pinning centers (as confirmed by modified Dew Hughes model) were identified to be responsible behind the variation in Tc and Jc.
References
[1] L. Zeng, L. Li, K. Li, R. Chen, and H. Luo, “Recent advances in high-entropy superconductors,” NPG Asia Mater, vol. 16, no. 1, pp. 1-13, Nov. 2024, doi: 10.1038/s41427-024-00579-z.
[2] N. Srivastava and S. Santra, “A novel bulk (Nb,Zr,Pt)67Ti33 high-entropy alloy superconductor: synthesis and structure-property relationship,” J. Mater. Chem. C, p., 2024, doi: 10.1039/D4TC01500B.

Manganese (Mn) additions lead to the formation of dispersoids in aluminium alloys and these nano-scale precipitates inhibit both grain nucleation and grain boundary migration. In this work, the effect of Mn additions was investigated for a recrystallized AA6xxx. Both microstructural aspects and mechanical properties were evaluated. The results showed that increasing the Mn content changed grain shape and increase grain size where Cube textured recrystallized grains overgrew and it was accompanied by a small reduction of strength. Mn addition increases dispersoid precipitation which reduces fraction of high-angle grain boundaries while increasing low-angle boundaries. This indicates obstructing recrystallisation while promoting recovery.

Recycled aluminum in tailor-welded blanks (TWBs) offers a sustainable solution for automotive applications. However, its higher impurity levels and poorer weldability compared to primary aluminum adversely affect both strength and formability, limiting its usage. This study aims to investigate how differences in microstructural and mechanical anisotropy between primary and recycled AA6082-T6 aluminum alloys affect the mechanical integrity of TWBs joined through friction stir welding (FSW). The two extrusions were welded at a rotational speed of 1000 rpm and a welding speed of 60 mm/min, with weld line orientations of 0°, 45°, and 90° relative to the extrusion direction of the base metals (BMs). Prior to welding, tensile tests were conducted to evaluate the uniform and fracture strains of BMs in different orientations, determining the alloys' mechanical anisotropy. Results indicate that weld line orientation less affected the transverse tensile properties, but the stir zone (SZ) showed orientation-dependent tensile properties in the longitudinal direction relative to the base metal. The SZ demonstrated an increase in the fracture strain to 29% along the weld direction and a drop in yield strength to 195 MPa, which are significant values compared to the 16% fracture strain and 332 MPa yield strength observed in the BM extrusion direction. Furthermore, SEM-EBSD analysis revealed that the recrystallized grain size within the SZ varied with weld line orientation, influencing both hardness and tensile properties in the longitudinal direction. Specifically, the grain size decreased from approximately 10 µm in the 0° orientation to 6 µm in the 90° orientation. The degree of grain refinement increased with weld thickness with coarser grains at the top and finer grains at the bottom of the stir zone.

Magnesium and its alloys have attracted considerable research attention in recent decades due to their advantageous properties, including high specific strength and reasonable price, making them promising candidates for aerospace applications. However, their wider application is limited by several drawbacks such as low corrosion resistance, susceptibility to ignition, and limited ductility.
This study examines three newly developed magnesium alloys—Mg-4Ca-1Y, Mg-4Ca-1Y-1Zn, and Mg-4Ca-1Y-1Al-1Zn (wt.%) — designed specifically for aerospace applications. These alloys were prepared by extrusion, and their microstructure, mechanical properties, and flammability resistance were systematically analyzed.
Extrusion processing resulted in an almost fully recrystallized microstructure with an average grain size of less than 2 µm across all examined alloys. Uniaxial compression and tensile tests, combined with digital image correlation measurements, demonstrated that all alloys exhibit high strength, with a yield strength exceeding 260 MPa in both tension and compression. Notably, the Mg-4Ca-1Y-1Zn alloy displayed excellent ductility, with an extension to fracture greater than 12%.
Flammability resistance was studied through ignition temperature measurements and torch flammability testing. All alloys exhibited ignition temperatures above 1050 °C, attributed to the protective effectiveness of the CaO + Y₂O₃ bi-oxide layer. Furthermore, torch flammability tests confirmed that these materials are non-flammable, even under direct flame exposure.

This study explores how varying the duration of plasma electrolytic oxidation (PEO) treatment affects the corrosion resistance of Mg-1Zn and Mg-1Zn-0.4Ca alloys. These results are compared to pure magnesium and the commercial alloy Mg-4Y-3RE-0.4Zr alloy. PEO coatings were applied for various durations, and subsequently, microstructure, surface morphology, and corrosion performance were examined. Among the different durations, the 10-minute treatment produced the most uniform coatings and offered superior protection against corrosion. In contrast, longer treatment times led to thicker layers with more pores and cracks, which accelerated degradation during immersion in a 0.9% NaCl solution. The gradual dissolution of phosphates from the PEO layer facilitated the development of a protective corrosion film, further enhancing durability over time. Overall, the results show that with proper surface modification, low-alloyed Mg-Zn(-Ca) systems can match the corrosion resistance of more complex, high-performance alloys like WE43—making them promising candidates for biodegradable and biocompatible applications.

A selection of alloys from the Mg-Li-Y system designed for biodegradable orthopedic implant applications was processed by hot-extrusion and, subsequently, by equal channel angular pressing (ECAP). The effect of the severe plastic deformation technique on the microstructure, mechanical properties, and corrosion resistance was investigated. After the ECAP processing, the single-phase matrix Mg-2Li-2Y, Mg-2Li-4Y, Mg-4Li-2Y, and Mg-4Li-4Y alloys (wt. %) exhibited nearly fully dynamically recrystallized fine-grained microstructure. In contrast, the dual-phase hcp + bcc Mg-8Li-1Y alloy exhibited a bimodal structure of the hcp α-phase. All the investigated alloys exhibited excellent ductility during tensile loading. Whereas in the as-extruded state, the single-phase alloys generally (except for the Mg-4Li-4Y) lacked strength, the grain refinement led to significant strengthening while retaining the ductility. Despite significant grain refinement in the hcp α-phase of the Mg-8Li-1Y, its mechanical performance remained virtually unchanged. The alloys in the as-extruded state have proved more resistant to the initial corrosion attack. In contrast, the longer-term corrosion resistance evaluated based on the immersion tests was improved due to the additional ECAP processing.

This study investigates the feasibility of processing the Zn0.4Mg0.4Ca alloy using Selective Laser Melting (SLM) for potential application in biodegradable medical implants. As part of the initial phase of a broader research effort, five test samples were successfully printed and subjected to basic material characterization. Microhardness measurements yielded an average of 115.2 HV1, significantly exceeding the hardness of pure zinc, indicating the strengthening effect of the alloying elements. Surface roughness analysis revealed significant anisotropy, with Ra values of 10.76 µm parallel and 25.69 µm perpendicular to the build layers, underscoring the need for additional surface post-processing. The measured density was high and slightly exceeded theoretical expectations, indicating excellent structural compaction and low porosity. These findings confirm the alloy’s printability and provide a solid foundation for future research focused on printing and evaluating specific implant geometries, including mechanical, microstructural, and biocompatibility assessments.

Metallurgy is one of the industrial sectors that very well express the basic principles of the circular economy. This study presents the production of two main metals - zinc and lead - through the lens of the circular economy. The object of analysis is KCM-AD, Plovdiv, Bulgaria - a major producer of these metals for Southeast Europe. Exergy and environmental assessments have been made, using the exergy method of thermodynamic analysis. The resources - primary and secondary raw materials, products and emissions - gas emissions, wastewater and solid waste, and the methods used to minimize technogenic emissions have been assessed.

Eutectic and near-eutectic Sn-Zn alloys represent some of the most promising lead-free solder alloy alternatives. The eutectic Sn-9Zn alloy has a low melting point (199 ° C) that is very close to that of the eutectic Sn-Pb solder (183 °C). Furthermore, the alloys have favorable mechanical properties and a reasonable cost. However, challenges remain due to their low wettability and limited corrosion resistance. The Sn-Zn alloys are prone to corrosion since Zn is an electrochemically active element that can be easily oxidized. In the present work, the phase constitution, microstructure, and corrosion behavior of three binary Sn-xZn alloys (x = 5, 9 and 15 wt.%) were investigated. The results have been compared with those of pure Sn and Zn. The Sn-Zn alloys were prepared by induction melting of high purity Sn and Zn lumps in argon. After melting, the alloys were rapidly solidified in air to form cast cylinders. The Sn-9Zn alloy had a eutectic microstructure. The Sn-5Zn alloy was composed of dendritic Sn(ss) and eutectic. The Sn-15Zn alloy was composed of dendritic Zn(ss) and eutectic. The corrosion behavior of the Sn-Zn alloys was studied in aqueous NaCl and HCl solutions at room temperature. Corrosion potentials and corrosion rates in HCl were significantly higher compared to NaCl. The corrosion of binary Sn-Zn alloys was found to take place by a galvanic mechanism. Alloys with a higher concentration of Zn (Sn-9Zn, Sn-15Zn) formed corrosion products rich in Zn. The Zn-rich corrosion products were prone to spallation. On the other hand, the Sn-5Zn alloy formed corrosion products of Sn and had the lowest corrosion rate. It is demonstrated that the corrosion rate of the Sn-Zn alloys could be considerably reduced by reducing the weight fraction of Zn in the alloys.
This work was supported by the Slovak Research and Development Agency project number APVV-20-0124, by the Scientific Grant Agency of the Ministry of Education, Science, Research and Sports of the Slovak Republic and the Slovak Academy of Sciences project numbers VEGA 1/0389/22 and 1/0531/22 and the NextGenerationEU recovery package of the European Commission through the Recovery and Resilience Plan for Slovakia under the project No. 09I04-03-V02-00046.

Petrochemical catalysts from gudron hydrodesulphurisation plants are hazardous waste due to their content of petroleum fractions. However, they represent a valuable resource due to their high concentration of Ni, Mo and V. In order to recover the metals in an environmentally safe way, it is first necessary to remove the contained oil fraction.
Removal of the petroleum fraction was carried out by solvent extraction using hexane and pyrolysis. Removal of the petroleum fraction is designed to prepare the catalysts for the pyrometallurgical stage, which allows Ni, Mo and V to be recovered as a metallic alloy. The simultaneous extraction and pyrolysis process is supposed to reduce CO2 emissions during the pyrometallurgical step by removing the petroleum fraction before the pyrometallurgical step.
The research presented in this article is being carried out as part of the LIDER13/0133/2022 project funded by the National Centre for Research and Development, which aims to develop a complete technology for the recovery of Ni, Mo and V from spent petrochemical catalysts.

Manganese ore fines generated during manganese production are either partially recycled as agglomerates using binders, or stored, leading to pollution, and negative environmental impacts due to landfilling. Fines have for long been considered as environmental unfriendly, loss if not recycled and stage threats in the metallurgical industry if not taken care of. Several binders have been tested especially inorganic binders to recondition the fines to be recycled for metal production. However, inorganic binders have been found to be detrimental to the products due to impurities that they carry. The current investigation has focused on testing the impact of organic binders on manages briquettes made from ore fines. Alcotac CB6 was used in this investigation, a specific compression has been adopted to make manganese briquettes. Results have demonstrated that the optimal briquette specifications of the basic manganese ore fines for industrial briquetting tests are 1.2% Alcotac CB6 and 147 kN compressive strength. At these optimal specifications, the briquettes show a dry strength of 2750 kN after 48 hours of cool drying, which is strong enough to handle the mechanical abrasions of transportation in the plant, and the observed degree of disintegration is less than 5% proving to yield stable furnace operations.

La-Ni compounds are considered promising candidates for future hydrogen-storage applications. Some of the La-Ni phases have been insufficiently studied so far and some critically important data are missing. In particular, the La5Ni19 intermetallic compound is reported to crystallize in either hexagonal or rhombohedral R3 phase, but the stability of these two variants has not been satisfactorily addressed. We have employed quantum-mechanical calculations implementing the density functional theory (DFT) within the generalized gradient approximation (GGA) to determine the ground-state structural, electronic, thermodynamic, and elastic properties of the two phases. The hexagonal phase is described by a computational cell containing 48 atoms, while that of the rhombohedral phase contains 72 atoms. Both computational cells exhibit shapes that are strongly anisotropic. The computed results obtained for static lattices indicate that both phases are very similar with the hexagonal phase having a slightly lower formation energy (by 1 meV/atom) than the rhombohedral phase. The computational cell volumes and the total magnetic moments are practically identical in both phases. Further, the stress-strain method addressed the mechanical stability by computing a full tensor of the second-order elastic constants.
Acknowledgments
This study is a part of the project No. CZ.02.01.01/00/22_008/0004631 Materials and technologies for sustainable development within the Jan Amos Komensky Operational Program financed by the European Union and from the state budget of the Czech Republic. The authors acknowledge the Ministry of Education, Youth and Sports of the Czech Republic for the financial support of large research infrastructures CzechNanoLab (LM2023051), CEMNAT (LM2023037), INFRA CZ (ID:90254) at the IT4Innovations National Supercomputing Center and e-Infrastruktura CZ (e-INFRA LM2018140) at the MetaCentrum as well as CERIT Scientific Cloud and project CZ.02.01.01/00/22_008/0004572.

The recent progress in additive manufacturing increased the demand for high quality metal powders with tailored composition. The refractory complex alloys are peculiar for conventional metallurgy due to their high melting point and reactivity. In addition, the combination of our cold spray additive manufacturing and refractory complex concentrated alloys is suitable for cladding of heat sensitive parts. Radiofrequency plasma spheroidization provides powders with suitable collection of properties for such further processing. This work focuses on production of spherical powder of a selected refractory complex concentrated alloy NbTiVZr from a powder produced by high energy milling from elemental commercial powders. Various processing parameters will be discussed in order to optimize the quality, homogeneity and powder size distribution. Each additive manufacturing method requires different size distribution of powder particles. However, powder sieving significantly decreases efficiency of production. Therefore, optimization of milling and spheroidization processes are crucial. Main focus of this study is to investigate microstructure of spheroidized powder particles from initially imperfectly milled powders with substantial degree of heterogeneity. High-enthalpy plasma reaction in protective atmosphere liquifies intermixed powder particles and thus interesting microstructures and phase composition are formed during fast cooling in the collector and on the walls of the spheroidization chamber. Such powder does not require complicated heat treatment nor surface reduction annealing and is ready for further additive manufacturing.

Zirconium alloys with minimal alloying elements have primarily been studied for use in nuclear reactors due to their low neutron capture cross-section. However, research on titanium alloys—members of the same group in the periodic table, which undergo similar phase transformations—suggests that incorporating higher levels of alloying elements and utilizing well-established strengthening mechanisms, such as multi-phase microstructures, can significantly improve mechanical properties. This enhancement may compensate for the increase in neutron capture cross-section. Despite this, the phase transformations in zirconium alloys remain relatively unexplored. Comparing these transformations with those of titanium alloys can provide a deeper understanding of their behavior. In this study, the phase transformations in metastable Zr-xNb (x=12,15) alloys were systematically investigated using high-energy X-ray diffraction (HEXRD) during linear heating. To complement the HEXRD data, additional in-situ techniques—specifically electrical resistance measurements and differential scanning calorimetry (DSC)—were employed under the same heating conditions, offering further insight into the transformation sequence in Zr-xNb alloys. In the solution-treated state, the alloys primarily consisted of the metastable β-Zr phase, along with athermal ω particles. At around 300 °C, the formation of an Nb-rich β-Nb phase was observed, coinciding with the gradual disappearance of the original β-Zr phase. At approximately 560 °C, the ω solvus was identified by a sharp dissolution of the ω particles, followed by the growth of the α phase.

Energy storage is one of the key challenges in achieving a complete transition to renewable energy sources, with hydrogen storage being one of the most promising solutions. Metal hydrides offer a viable platform for hydrogen storage. However, further research is needed to identify compositions that combine high hydrogen capacity with fast hydrogen capture and release at reasonable temperatures.
The La-Ni-Sn system is known for its intriguing structural and electronic properties, particularly in hydrogen storage and energy applications. The phase LaNi₅ and the ternary phase LaNiSn are known to form multiple hydrides. Most of these hydrides have not been extensively studied yet. Using a quantum-mechanical approach, we focus on one of the hydrides, the stoichiometric H₁LaNiSn phase, investigating its stability, equilibrium properties, phonons, electronic structure and hydrogen absorption behavior.
Our calculations are based on the Density Functional Theory (DFT) using the Vienna Ab initio Simulation Package (VASP). The Generalized Gradient Approximation (GGA) in the Perdew-Burke-Ernzerhof (PBE) parametrization was employed for the exchange-correlation functional and Projector Augmented Wave (PAW) potentials were used to describe the interaction between core and valence electrons. These calculations offer valuable information on the thermodynamic stability and electronic structure of the H₁LaNiSn phase, which are crucial for understanding its behavior in hydrogen storage applications.

We determined ground-state properties including the lattice parameters (a = 7.3115 Å, b = 8.6992 Å and c = 4.4593 Å), the electronic density of states as well as the phonon band structure and the temperature dependencies of thermodynamic quantities such as free energy, entropy and heat capacity within the harmonic approximation. Importantly, the H₁LaNiSn phase was found mechanically stable.

Acknowledgments
This study was created as part of the project No. CZ.02.01.01/00/22_008/0004631 Materials and technologies for sustainable development within the Jan Amos Komensky Operational Program financed by the European Union and from the state budget of the Czech Republic. The authors acknowledge the Ministry of Education, Youth and Sports of the Czech Republic for the financial support of large research infrastructures CzechNanoLab (LM2023051), CEMNAT (LM2023037), INFRA CZ (ID:90254) at the IT4Innovations National Supercomputing Center and e-Infrastruktura CZ (e-INFRA LM2018140) at the MetaCentrum as well as CERIT Scientific Cloud and project CZ.02.01.01/00/22_008/0004572.

Single-stage copper production in a flash furnace results in waste slag with a copper content exceeding 10%. Such copper losses are unacceptable in industrial production due to economic and environmental reasons. To recover copper from the slag, resistance electric furnaces are used, in which the reduction of oxidized metals is carried out. As a result of the slag reduction process, a CuFePb alloy is obtained. This process is highly energy-intensive, generating high costs and high CO2 emissions.
During the presentation, the results of numerical simulations of the electric furnace were presented. To perform the simulations, two submodels were coupled. The GetDP model (calculating the amount of Joule heat generated), which allows for the calculation of electrical current flow phenomena, and ANSYS Fluent, where hydrodynamic and thermal phenomena of the slag bath were calculated.
The simulation results were confirmed by performing trial slag melts in a laboratory electric furnace. To collect the required data (refractory lining and liquid slag temperatures), the laboratory furnace was modified and adapted for the installation of thermocouples in the lining and slag.
The results obtained from the tests conducted in the laboratory electric furnace showed good convergence of the computer simulation results. During the presentation, a comparison of temperatures obtained in the slag during actual measurements and calculations using GetDP and ANSYS Fluent software was presented.

Elementary plastic deformation events (dislocation avalanches, mechanical, martensitic transformation, etc.) are typically concealed in the deformation curves as the curves provide only “average information”. This is due to the simultaneous plastic activity at a multitude of locations within the sample as well as due to the limited force and time resolution of deformation devices. On the other hand, supplementary techniques such as high-resolution/ultra-fast imaging and acoustic emission, if implemented correctly, allow for detailed characterization of the activity of deformation mechanisms. Here, we apply these techniques to characterize metallic materials at macro- down to micro-scales, where the deformation behavior becomes rather erratic. Using these techniques, spatial and temporal patterns in seemingly random plastic events can be recognized by employing various statistical analyzes. The obtained data contribute to the fundamental understanding of deformation dynamics in crystalline materials and can be utilized in designing future metallic materials as well as emerging micron-size mechanical devices.

Quarry dust and concrete recycling dust, generated as solid waste during rock and concrete crushing operations, poses a significant environmental challenge. Rich in SiO₂, these fine-grained materials hold potential as fluxing agents in pyrometallurgical processes, yet their metallurgical applications remain underexplored due to the complexity of such waste streams. Within the FINEST project (https://finest-project.de/) , subproject 3 (FINEST Disperese Metals investigates the safe blending of multiple fine and ultra-fine grained industrial waste streams and their subsequent multi-stage pyrometallurgical processing for metal extraction and inert dispossal . Additionally, the Waelue project (https://www.recomine.de/en/project/waelue/) aims to valorize the Waelz slag, a byproduct of the well-established Waelz process for zinc extraction. Present study explores the feasibility of using quarry and concrete recycling dust as flux materials for the pyro-metallurgical processing of Waelz slag. A carbothermic reduction process was designed and experimentally tested, incorporating these dusts to in order to extract metals (Fe, Mn, Zn) and produce a declassified slag suitable as a construction material.FactSage™ was used to determine the optimal mixing ratio between the dusts and Waelz slag along with suitable reducing agent to achieve favorable smelting conditions. The results indicate that the incorporation of these dusts reduces the melting point and viscosity of the slag, facilitating efficient metal separation along with valorization of the fine particulate waste.These findings highlight the potential of integrating quarry and concrete recycling dust in pyrometallurgical processes, advancing waste valorization and aligning with circular economy principles for sustainable industrial byproduct recycling.

The subject of this work is the execution of mechanical testing of rigid ballistic protection based on composite materials.
The topic builds upon previously researched composite ballistic materials and extends the investigation of their mechanical properties by examining changes induced by exposure to ultraviolet (UV) electromagnetic radiation. The study utilizes existing research on the Twaron material and previously determined strength reduction values after one month of UV exposure. Experimental samples of composite plates made from this material will be manufactured using selected production technologies, based on prior analysis.
Mechanical properties of the experimental samples will be measured after four months of exposure to a defined UV environment, and these values will be compared. The aim of the practical tests is to assess the influence of manufacturing technology and environmental exposure on the mechanical properties of the composite ballistic materials.