1. Influence of isothermal annealing in the 600 to 750 °C range on the degradation of SAF 2205 duplex stainless steelJaka Burja, Borut Žužek, Barbara Šetina, 2024, izvirni znanstveni članek Povzetek: We studied the effect of isothermal annealing (600–750 °C, 1 to 1000 min) on the microstructure
and mechanical properties of SAF 2205 duplex stainless steel. Impact toughness was found
to be significantly more affected than hardness by annealing. Annealing at 750 °C for 1000 min
resulted in a more than 90% decrease in impact toughness, while hardness only increased by 25%.
Tensile strength increased up to 100 MPa, but elongation decreased by more than 50% under the
same conditions. Sigma phase formation was minimal at lower temperatures (650 °C and below)
but increased significantly at higher temperatures. At 750 °C and 1000 min of annealing, the ferrite
content dropped from 50% to 16%. These findings suggest that annealing temperature and time need
to be carefully controlled to avoid a reduction in impact toughness and ductility caused by sigma
phase precipitation. The harmful effect of sigma phase precipitation on mechanical properties was
directly shown.
Ključne besede: duplex stainless steel, sigma phase, precipitation kinetics, mechanical properties, isothermal annealing
Objavljeno v DiRROS: 24.07.2024; Ogledov: 91; Prenosov: 81
 Celotno besedilo (20,91 MB)
Gradivo ima več datotek! Več... |
2. Microstructural, corrosion and mechanical properties of a WE43 alloy : conventional extrusion versus SPDAnna Dobkowska, Aleksandra Zielińska, Irena Paulin, Črtomir Donik, Milena Koralnik, Bogusława Adamczyk-Cieślak, Monika Wieczorek-Czarnocka, Dariusz Kuc, Jiří Kubásek, Tomasz Mikuszewski, Matjaž Godec, Jarosław Mizera, 2024, izvirni znanstveni članek Povzetek: A hexagonal close-packed-structure WE43 alloy was extruded without any preheating of the initial billet using extrusion with an oscillating die to improve the corrosion and mechanical properties. The WE43 alloy was extruded at high ratios of R 1 5:1, R 2 7:1 and R 3 10:1. Electron back-scatter diffraction and transmission electron microscopy were used to determine the microstructural properties of the alloys. The influence of the extrusion method and the extrusion ratios on the corrosion and mechanical properties were investigated. Electrochemical tests were performed, and the corrosion damage was inspected. Tensile tests were made using micro specimens. When compared to conventional extrusion, the microstructural changes obtained with the KoBo method at R 5:1 increased the corrosion resistance, which was not only due to the grain refinement, but also due to the intensity of the texture. A decline in the corrosion resistance of the alloys deformed at higher extrusion ratios was observed. This was a result of the massive plastic strain imposed by the KoBo die. The room-temperature mechanical properties of the KoBo-extruded alloys were improved. However, at higher temperatures the mechanical properties decreased due to the solutioning of tiny triple precipitates.
Ključne besede: WE43, several plastic deformation, microstructure, corrosion, mechanical properties
Objavljeno v DiRROS: 23.07.2024; Ogledov: 93; Prenosov: 32
 Povezava na datoteko |
3. Microstructure and properties of an AZ61 alloy after extrusion with a forward-backward oscillating die without preheating of the initial billetAnna Dobkowska, Aleksandra Zielińska, Irena Paulin, Črtomir Donik, Maciej Łojkowski, Milena Koralnik, Bogusława Adamczyk-Cieślak, Krystian Paradowski, Marek Tkocz, Dariusz Kuc, Jiří Kubásek, Matjaž Godec, Wojciech Święszkowski, 2023, izvirni znanstveni članek Ključne besede: magnesium alloys, severe plastic deformation, microstructure, mechanical properties, corrosion, extrusion, high deformation ratio
Objavljeno v DiRROS: 17.05.2024; Ogledov: 247; Prenosov: 167
Povezava na datoteko |
4. 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: 309; Prenosov: 81
Povezava na datoteko |
5. 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: 322; Prenosov: 141
Celotno besedilo (681,81 KB)
Gradivo ima več datotek! Več... |
6. 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: 270; Prenosov: 123
Celotno besedilo (10,97 MB)
Gradivo ima več datotek! Več... |
7. |
8. 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: 255; Prenosov: 159
Celotno besedilo (4,44 MB)
Gradivo ima več datotek! Več... |
9. |
10. 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: 470; Prenosov: 146
Celotno besedilo (1,44 MB)
Gradivo ima več datotek! Več... |
