11. The effect of heat treatment on the interface of 155 PH martensitic stainless steel and SAF 2507 duplex steel in functionally graded AM componentsMartina Koukolíková, Pavel Podaný, Sylwia Rzepa, Michal Brázda, Aleksandra Kocijan, 2023, izvirni znanstveni članek Povzetek: Multi-material components, also known as functionally graded materials (FGMs), are innovative materials that possess unique properties due to their composition and have many potential applications in engineering and science. The effect of the heat treatment (HT) of functionally graded materials 15–5 precipitation-hardened (PH) martensitic steel and SAF 2507 duplex stainless steel (and the opposite order of deposition, i.e. SAF 2507 first followed by 15–5 PH stainless steel) on the interface microstructures was systematically investigated in the presented research. The choice of HT followed the trend of optimum post-processing for the individual alloys. A significant modification in the interface microstructure, characterized in the microstructural transition zone (MTZ) formed above the fusion line. Mechanical properties by miniaturized testing method including hardness measurement characterized both types of interfaces. The sequence of the materials’ application did not have a significant effect on their final mechanical tensile properties in the heat-treated states. Nevertheless, the microstructural change at the MTZ led to drop in the hardness at the interface. The research presents heat-treated FGMs in a horizontal configuration to form a high-quality metallurgical joint between heterogeneous materials manufactured by powder-based directed energy deposition method. Ključne besede: heat treatment, additive manufacturing, martensitic stainless steel, duplex steel, microstructure, mechanical properties Objavljeno v DiRROS: 04.04.2024; Ogledov: 330; Prenosov: 96 Povezava na datoteko |
12. Characterization and Mechanical Properties of Sintered Clay MineralsSara Tominc, Vilma Ducman, Jakob Koenig, Srečo D. Škapin, Matjaž Spreitzer, 2024, objavljeni znanstveni prispevek na konferenci Povzetek: The need to reduce energy consumption and the carbon footprint generated by firing ceramics has stimulated research to develop sintering processes carried out at lower temperatures(ideally not above 300 °C) and high pressures (up to 600 MPa), the so-called cold sintering process (CSP) (Grasso et al., 2020, Maria et al., 2017). To evaluate the applicability of CSP to clays, we focused on two representative clay minerals, kaolinite and illite, and on the natural clay material obtained from a Slovenian brick manufacturer. The selected clay materials were characterized on the basis of mineralogical-chemical composition (XRD, XRF) and particle size distribution (SEM analysis, PSD, BET). The powders of clay minerals and natural clay material were first sintered in a heating microscope to determine the sintering conditions and then in a laboratory furnace at 1100 °C for 2 hours and additionally at 1300 °C for kaolinites. The effect of compression of the initial powders on their final properties was also investigated. Ključne besede: conventional sintering, cold sintering, clay minerals, characterization, mechanical properties Objavljeno v DiRROS: 29.03.2024; Ogledov: 350; Prenosov: 159 Celotno besedilo (681,81 KB) Gradivo ima več datotek! Več... |
13. Međuodnos svojstava rasta i kvalitete drva na pokusnoj plohi arišaMirzeta Memišević Hodžić, Sulejman Sinanović, Dalibor Ballian, 2023, izvirni znanstveni članek Povzetek: Larch (Larix decidua) showed good growth and adaptability to ecological conditions in Bosnia and Herzegovina. The research aims to determine the variability of the morphological traits of larch in the seed stand near Kakanj, the variability at the beginning of heartwood formation, and correlations among these properties.In the larch seed stand, established by seedlings 2+0 in 1979, an area of 0,45 hectares was set aside. The heights and breast height diameters of the trees were on that area were measured in 2002 and 2020, and the basal area and volume were calculated. In 2020, the trees were drilled at breast height with a Presler drill to measure the proportion of heartwood. Average values of all properties for 2002 and 2020 were calculated. The ten, five and one best trees were selected according to the properties of breast height diameter, height, basal area, volume, and the intensities of selection for these traits were calculated. The Pearson correlation coefficient among all investigated traits were calculated. The average breast height diameter of 41-year-old trees was 24,6 cm, average height 21,8 m, basal area 0.0499m2 and volume 0.3745 m3 (table 1), while in 2002. the average breast height diameter was 15,5 cm, height 18,2 m, basal area 0,020 m2, and volume 0,128 m3 (table 1). Between 2002 and 2020, there was an overtaking of trees in breast height diameter and height and thus the base and volume (table 2). The average larch tree starts heartwood formation at the age of 14 years (table 1). The earliest heart-wood formation occurs in the sixth year (tree 495) and the latest in the 32nd year (table 4). Pearson coefficient showed a high positive correlation between breast height diameter and height in 2002 (ta-ble 9), which means that trees with a good height increase also have a good thickness increase. As a result, the correlation between breast height diameter and basal area and breast height diameter and volume, height and basal area, height and volume, and basal area and volume are statistically signifi-cant. Pearson’s correlation coefficient for the year 2020 showed a negative correlation between the be-ginning of heartwood formation and all other traits (table 10), i.e., trees that formed heartwood earlier have higher values of growth traits.The results will be used in the selection processes of larch individuals with good height and thickness growth and early heartwood formation. Ključne besede: European larch, morphological properties, core formation, selection Objavljeno v DiRROS: 25.03.2024; Ogledov: 364; Prenosov: 230 Celotno besedilo (255,90 KB) Gradivo ima več datotek! Več... |
14. A comparative analysis among quenched, tempered, and stepped cooled TIG welded SS-304 plates based on tensile strength, hardness, and microstructural appearanceSaurabh Dewangan, Saksham Saksham, Adhir Chandra Paul, Jaka Burja, 2023, izvirni znanstveni članek Ključne besede: welding, austenitic stainless steel, heat affected zone, mechanical properties Objavljeno v DiRROS: 15.03.2024; Ogledov: 297; Prenosov: 141 Celotno besedilo (10,97 MB) Gradivo ima več datotek! Več... |
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16. Evolution of microstructure and embrittlement during the tempering process in SiCrCu medium-carbon steelsPavel Salvetr, Aleksandr Gokhman, Črtomir Donik, Zbyšek Nový, Jakub Kotous, Matjaž Godec, 2023, izvirni znanstveni članek Ključne besede: medium-carbon steel, tempering martensite embrittlement, microstructure, mechanical properties Objavljeno v DiRROS: 08.03.2024; Ogledov: 299; Prenosov: 183 Celotno besedilo (4,44 MB) Gradivo ima več datotek! Več... |
17. The use of paper industry side product in constructionBarbara Likar, Laura Vovčko, 2020, objavljeni znanstveni prispevek na konferenci Povzetek: The amount of waste material and side products of various industrial plants is increasing, which leads into waste accumulation and lack of space in disposal landfills. Paper industry, with its side products paper sludge and ash, faces these same issues. To reduce the accumulation of these materials, we explored the possibility of their use in construction. At first a series of geomechanical tests was conducted on a product consisting of fly ash and bottom ash. Based on the laboratory results test fields were constructed, where the preparation and installation technologies were tested. The fields were exposed to the atmospheric conditions, so durability of the product in the natural environment was proven. Since the composition of both fly ash and bottom ash depends on the paper industry process, a continuous monitoring of their characteristics was established. Ključne besede: paper industry, fly ash, bottom ash, construction material, geomechanical properties Objavljeno v DiRROS: 05.03.2024; Ogledov: 344; Prenosov: 142 Celotno besedilo (521,45 KB) Gradivo ima več datotek! Več... |
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19. Possibilities for improvement of mechanical properties of high-strength medium-carbon SiCr steelsPavel Salvetr, Jakub Kotous, Črtomir Donik, Aleksandr Gokhman, Zbyšek Nový, 2023, izvirni znanstveni članek Ključne besede: spring steel, 54SiCr6 steel, microstructure, mechanical properties Objavljeno v DiRROS: 02.02.2024; Ogledov: 495; Prenosov: 162 Celotno besedilo (1,44 MB) Gradivo ima več datotek! Več... |
20. Austenite reversion suppression with deep cryogenic treatment : a novel pathway towards 3rd generation advanced high-strength steelsPatricia Jovičević Klug, Matic Klug Jovičević, Lars Thormählen, Jeffrey McCord, Michael Rohwerder, Matjaž Godec, Bojan Podgornik, 2023, izvirni znanstveni članek Ključne besede: Martensitic stainless steel, deep cryogenic treatment, microstructure, mechanical properties, microstructural transformations, phase transformation Objavljeno v DiRROS: 02.02.2024; Ogledov: 375; Prenosov: 175 Celotno besedilo (13,70 MB) Gradivo ima več datotek! Več... |