Ádám Vida

The cross-sectional microstructure, local chemical composition, and mechanical behavior of anodic oxide layers produced by oxalic acid anodizing of cast A356 aluminum alloy were investigated using digital optical microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and in situ nanoindentation inside the SEM chamber. The anodized specimens contained a compact oxide-side interfacial region adjacent to the substrate–oxide interface and an outer porous oxide layer. The oxide layers formed at the higher nominal charge density were generally thicker than those formed at the lower charge density. Cross-sectional nanoindentation revealed two characteristic interface-related features: localized, unusually high apparent hardness values on the oxide side of the interface and a gradual hardness increase within the adjacent substrate-side region. The highest apparent values exceeded the expected hardness range of anodic oxide layers on A356 alloy and were therefore interpreted as interface-affected responses rather than intrinsic oxide hardness values. Their repeated occurrence at a well-defined position nevertheless supported their association with the oxide-side interfacial region. The substrate-side hardness increase was characterized by the estimated width of an anodizing-affected substrate zone. EDS line scans showed that the oxide-side interfacial region retained a significant oxygen concentration, whereas the substrate-side hardness increase was not accompanied by a systematic elemental concentration gradient. The results demonstrate that the cross-sectional mechanical response of oxalic-acid-anodized A356 alloy is governed not only by the conventional barrier-layer–porous-layer structure, oxide thickness, and porosity, but also by local chemical composition, microstructural heterogeneity, and substrate/interface-related effects.

A krónikus myeloid leukaemia kezelésében széleskörűen használt BCR/ABL1 tirozin-kináz-gátlóknak számos cardiovascularis mellékhatásuk ismert. Ezek közé tartozik a precapillaris pulmonalis hypertonia is. Ezen mellékhatások a tirozin-kináz-gátlók dózisának csökkentésével, a terápia felfüggesztésével vagy más tirozin-kináz-gátlóra való váltással sok esetben reverzibilisek, emiatt időben történő felismerésük fontos. Esetünk értékét a gyors felismerésen túl a Swan–Ganz-katéterezéssel megerősített pulmonalis hypertonia, a tirozin-kináz-gátló bosutinib elhagyását követő gyors klinikai javulás és a szabályossá váló pulmonalis nyomás adja.

High-entropy alloys (HEAs) represent one of the most promising emerging material families, particularly for advanced surface engineering applications. In this work, a near-high-entropy alloy (near-HEA) coating was produced on a 316L stainless steel substrate using laser metal deposition (LMD) from a powder mixture of Inconel 625, Cr and Mo, without the intentional addition of Fe. Due to dilution from the substrate, the resulting alloy contained elevated Fe content while maintaining Cr, Ni and Mo concentrations within the generally accepted compositional range of HEAs. The deposited layer exhibited a dual-phase microstructure consisting of a face-centered cubic (FCC) phase and a highly distorted tetragonal phase forming a periodic network with a characteristic length scale of several hundred nanometers. The hardness of the coating increased to approximately three times that of the substrate, reaching values of 600–700 HV. To further modify the surface properties, laser-induced periodic surface structures (LIPSS) were generated on the polished coating using femtosecond pulsed laser irradiation at different energy densities. The morphology and subsurface structure of the resulting periodic patterns were investigated by scanning electron microscopy. LIPSS with characteristic dimensions ranging from the micrometer to nanometer scale were successfully produced. Cross-sectional analyses revealed that the underlying dual-phase microstructure remained continuous within the laser-structured regions, indicating that LIPSS formation occurred predominantly via metallic ablation without significant phase transformation or amorphization. These results demonstrate the combined applicability of LMD and femtosecond laser structuring for producing mechanically enhanced, micro- and nanostructured near-HEA coatings with potential for advanced surface-related functionalities.

This study explores the fabrication of an equimolar CoCrFeNi high-entropy alloy (HEA) using laser metal deposition (LMD) technique on a 316 L austenitic stainless steel substrate, without pre-alloying. Elemental metal powders were mixed in a planetary ball mill and directly deposited to investigate the effect of layer number on alloy composition and substrate intermixing. Experimental results revealed significant dilution in the first four layers, with substrate intermixing affecting composition. The coarse-grained crystal structure observed in the initial layers persisted in subsequent layers, and hardness measurements indicated the cumulative thermal effects of sequential deposition. From an industrial perspective, this approach offers a cost-effective and flexible manufacturing strategy, eliminating the need for pre-alloying. Moreover, gradient compositional layers can be achieved, enabling tailored material properties. This work demonstrates the feasibility of producing multi-layer HEAs directly from elemental powders while addressing the challenges of compositional stability.

Regular wave patterns were created by a 2 kV gallium ion on Si(111) monocrystals at incidence angles between 60° and 80° with respect to the surface normal. The characteristic wavelength and surface roughness of the structured surfaces were determined to be between 35–75 nm and 0.5–2.5 nm. The local slope distribution of the created periodic structures was also studied. These topography results were compared with the predictions of the Bradley–Harper model. The amorphised surface layers were investigated by a spectroscopic ellipsometer. According to the results, the amorphised thicknesses were changed in the range of 8 nm to 4 nm as a function of ion incidence angles. The reflectance of the structured surfaces was simulated using ellipsometric results and measured with a reflectometer. Based on the spectra, a controlled modification of reflectance within 45% and 50% can be achieved on Si(111) at 460 nm wavelength. According to the measured results, the characteristic sizes (periodicity and amplitude) and optical property of silicon can be fine-tuned by low-energy focused ion irradiation at the given interval of incidence angles.

The A356 alloy is commonly used in the foundry industry to produce high-stressed automotive components, such as motor frames and cylinder heads. The aim of this work was to investigate how the mechanical and tribological properties of this alloy can be improved by applying an anodizing process. The properties of the oxide layer formed by anodizing using oxalic acid at low temperatures were characterized by different analytical and tribological methods. The combination of tribological methods with standard measurement techniques—such as hardness measurement, layer thickness measurement, as well as the analysis of the morphological characteristics—was used to track the layer evolution during wear developments.

The A356 aluminum alloy is a very commonly used alloy in the automotive industry, for parts such as pistons, cylinder heads, and connecting rods, for which the mechanical properties can be effectively increased by anodizing. In this work, oxide layers were formed in oxalic acid solution with defined parameters on A356 aluminum alloy and then studied by using a novel combination of the scanning electron microscope (SEM) and in-situ nanoindentation. The purpose of this research is to understand the relationship between the substrate and the oxide layer by examining its microstructure and nanohardness. Based on the experimental results showing special composite microstructure and corresponding high hardness, this alloy seems to be a good alternative for replacing steel brake disks in an environmentally conscious manner.

This paper investigates the phenomenon of Laser-induced Periodic Surface Structures (LIPSS) on Si single crystals. As usual, by variation of parameters, the morphological and physical properties of the resulting surfaces can be tailored, with respect to their use in many applications. One application-oriented use of LIPSS is the preparation of SERS (Surface Enhanced Raman Spectroscopy) substrates, which can be used to detect extremely low concentrations of molecules. In this experimental work, a possible way of manufacturing of SERS substrates, followed by SERS enhancement testing has been shown.

The present investigation is directed to phase transitions in the equimolar NiCoFeCrGa high entropy alloy, which is a mixture of face-centered cubic (FCC) and body-centered cubic (BCC) crystalline phases. The microstructure of the samples was investigated by using scanning electron microscopy (SEM), time-of-flight secondary ion mass spectroscopy (TOF-SIMS), transmission electron microscopy-based energy-dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS), as well as X-ray diffraction (XRD) measurements. Based on the phases observed in different temperature ranges, a sequence of the phase transitions can be established, showing that in a realistic process, when freely cooling the sample with the furnace from high to room temperature, a microstructure having spinodal-like decomposition can also be expected. The elemental mapping and magnetic behaviors of this decomposed structure are also studied.