1. Additive manufacturing multi-material components of SAF 2507 duplex steel and 15-5 PH martensitic stainless steelMartina Koukolíková, Pavel Podaný, Sylwia Rzepa, Michal Brázda, Aleksandra Kocijan, 2023, izvirni znanstveni članek Povzetek: The study reports the successful deposition of 15–5 precipitation-hardened (PH) martensitic steel on SAF 2507 duplex stainless steel (and vice versa) to form functionally graded materials (FGMs) using powder-based, directed-energy-deposition (DED) technology. The evolution of the microstructure and the mechanical properties of the 15–5 PH/SAF 2507 functionally graded material in the as-built state were investigated systematically. The results proved that the microstructural transition zone (MTZ) is formed above the fusion line due to the dilution effect of both steels. The phase composition of the MTZ consists of ferrite and, in comparison to the base materials, an increased amount of austenite. The interface has the lowest hardness owing to the formation of a significant proportion of the austenitic phase. However, the tensile mechanical properties were not affected by the interface as failure occurred in both SAF 2507 and at the interface regions. The research presents a promising application of FGMs in a horizontal configuration to form a high - quality, metallurgical joint between heterogeneous materials. This study introduces a novel approach by additive manufacturing (AM) of heterogeneous multi-materials, merging the favorable properties of duplex SAF 2507 and martensitic 15-5 PH stainless steels through superior metallurgical bonding. The combination of SAF 2507 and 15-5 PH in a functionally graded material has not been previously explored, as the existing studies deal with the duplex stainless steels SAF 2507 and either martensitic stainless-steel 15-5 PH deposited separately by laser powder-bed-fusion (L-PBF) or DED methods. This research pioneers the investigation of these materials in tandem, paving the way for the development of novel FGMs with optimized properties for specific applications. The resulting FGM exhibits exceptional corrosion resistance and high strength, making it highly versatile for applications in diverse industries such as offshore oil and gas production, aerospace, aviation, and chemical processing equipment.
Ključne besede: directed energy deposition, functionally graded materials, miniaturized specimen testing methods, SAF 2507, 15-5 PH
Objavljeno v DiRROS: 04.04.2024; Ogledov: 46; Prenosov: 17
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2. Moss as a biomonitor to identify atmospheric deposition of minor and trace elements in MacedoniaRobert Šajn, Katerina Bačeva Andronovska, Trajče Stafilov, Lambe Barandovski, 2024, izvirni znanstveni članek Povzetek: The present work was carried out to obtain and highlight the fifth comprehensive baseline dataset on atmospheric deposition of trace elements and to assess air quality in Macedonia. In the period from August to September 2020, a total of 72 moss samples were collected in accessible areas in the country. The content of 28 elements (Ag, Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Sr, Ti, U, and Zn) was determined using inductively coupled plasma–mass spectrometry. Based on the data obtained on the content of the elements, a factor analysis was carried out to identify and characterise different sources of pollution. In addition, distribution maps were created for all elements to show the regions most affected by anthropogenic activities. The survey conducted in 2020 has shown that air pollution with potentially toxic elements (PTEs) has slightly decreased compared to the results of the previous survey from 2015. This is due to the fact that, despite the operation of all mining and smelting facilities with the same capacity, government regulations for the installation of cleaning systems and additional regulations to reduce pollution have been introduced in the last five years. Nevertheless, the fact remains that the highest anthropogenic air pollution with PTEs is still caused by the operation of the ferronickel smelter in Kavadarci (Ni and Cr) in the southern part and by the lead and zinc mines in Probištip, Makedonska Kamenica, and Kriva Palanka in the eastern part of the country (Cd, Pb, and Zn).
Ključne besede: moss, atmospheric deposition, trace elements, air quality, Macedonia
Objavljeno v DiRROS: 20.03.2024; Ogledov: 76; Prenosov: 30
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3. Characterisation of the microstructure and defects during the direct energy deposition of hybrid Ti6Al4V in a low-quality atmosphereSimon Malej, Črtomir Donik, Matej Balažic, Matija Bizjak, Marko Kač, Matjaž Godec, 2023, izvirni znanstveni članek Ključne besede: direct energy deposition, Ti6Al4V, protective atmosphere
Objavljeno v DiRROS: 08.03.2024; Ogledov: 91; Prenosov: 48
Celotno besedilo (3,66 MB)
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4. Characterization of atmospheric deposition as the only mineral matter input to ombrotrophic bogValentina Pezdir, Martin Gaberšek, Mateja Gosar, 2022, izvirni znanstveni članek Povzetek: Ombrotrophic peatlands contain a very small percentage of mineral matter that they receive exclusively from atmospheric deposition. Mineral matter deposited on the Šijec bog was characterized using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). We collected solid atmospheric deposition from snow, rainwater, and using passive samplers. Samples were collected at average atmospheric conditions and after two dust events. Size, morphology, and chemical composition of individual particles were determined. We distinguished four main particle groups: silicates, carbonates, organic particles, and Fe-oxyhydroxides. Silicate particles are further divided into quartz and aluminosilicates. Proportions of these groups vary between samples and between sample types. In all samples, silicate particles predominate. Samples affected by dust events are richer in solid particles. This is well observed in passive deposition samples. Carbonates and organic particles represent smaller fractions and are probably of local origin. Iron-oxyhydroxides make up a smaller, but significant part of particles and are, according to their shape and chemical composition, of both geogenic and anthropogenic origin. Estimated quantity and percentage of main groups vary throughout the year and are highly dependent on weather conditions. Dust events represent periods of increased deposition and contribute significantly to mineral matter input to peatlands.
Ključne besede: atmospheric deposition, SEM/EDS, mineral matter, peatland
Objavljeno v DiRROS: 08.09.2022; Ogledov: 531; Prenosov: 246
Celotno besedilo (3,51 MB)
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5. Elemental associations in stream and alluvial sediments of the Savinja and Voglajna Rivers (Slovenia, EU) as a result of natural processes and anthropogenic activitiesGorazd Žibret, 2022, izvirni znanstveni članek Povzetek: Stream and alluvial sediments of the Savinja and Voglajna rivers were sampled, and sediment fractions <0.063 and 0.063–0.125 mm were analyzed on the content of 60 of the main and trace elements. The objective was to determine elemental associations and identify possible sources of these associations. Differences of Al/Ti oxides ratio (9.7–26) can be attributed to the variations in the source rocks, while the K/Al oxides ratio indicates erosional or depositional river regime and variation in source rocks. One anthropogenic and three natural associations of elements were identified. The anthropogenic association (Ag, In, Sb, Cu, As, Zn, Pb, Cd, Bi, Mo and Sn) is linked to historic Zn smelting in the Celje area, and the subsequent erosion of the material from inadequately managed pyrometallurgical waste deposit. The second association (Li, Sc, Al, V, Cs and Ga) is linked to clay minerals, the third one (Mg, Ca and Te) to carbonate rocks, and the fourth one (Hf, Zr) to the heavy mineral fraction.
Ključne besede: heavy metals, smelting, weathering, erosion, deposition, farming, waste
Objavljeno v DiRROS: 06.07.2022; Ogledov: 551; Prenosov: 387
Celotno besedilo (5,57 MB)
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