1. Dispersoids in Al-Mg-Si alloy AA 6086 modified by Sc and YFranc Zupanič, Sandi Žist, Mihaela Albu, Ilse Letofsky-Papst, Jaka Burja, Maja Vončina, Tonica Bončina, 2023, izvirni znanstveni članek Ključne besede: aluminijeve zlitine, toplotna obdelava, mikrostruktura, disperzoidi, dilatometrija, trdota, aluminium alloy, heat treatment, microstructure, dispersoids, dilatometry, DSC, hardness
Objavljeno v DKUM: 05.04.2024; Ogledov: 183; Prenosov: 21
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3. Microstructure, mechanical properties and fatigue behaviour of a new high-strength aluminium alloy AA 6086Franc Zupanič, Jernej Klemenc, Matej Steinacher, Srečko Glodež, 2023, izvirni znanstveni članek Opis: This study presents the comprehensive experimental investigation of the microstructure, mechanical and fatigue properties of a new high-strength aluminium alloy AA 6086, which was developed from a commercial aluminium alloy AA 6082. The new alloy possesses a higher content of Si, and, it also contains Cu and Zr. The alloy was characterised in the as-cast condition after homogenisation, extrusion, and T6 heat treatment. Light microscopy, scanning and transmission electron microscopy with energy dispersive spectrometry were used to analyse the microstructure and the fractography of broken specimens. The quasi-static and fatigue tests were performed on the MTS Landmark 100 kN servo-hydraulic test machine, controlled with a mechanical extensometer with a 25 mm gauge length. The quasi-static strength of the analysed aluminium alloy AA 6086 was found to be significantly higher if compared to some other AA 6xxx alloys, while the ductility was kept almost the same. The experimental results of the comprehensive fatigue tests in a Low Cycle Fatigue (LCF) and High Cycle Fatigue (HCF) regime showed a good fatigue resistance, and represent a good basis for engineering design applications of the newly developed aluminium alloy AA 6086.
Ključne besede: aluminijeve zlitine, karakterizacija materiala, utrujanje, eksperimentalno testiranje, statistično ovrednotenje, Aluminium Alloy AA 6086, material characterisation, fatigue behaviour, experimental testing, statistical evaluation
Objavljeno v DKUM: 02.04.2024; Ogledov: 281; Prenosov: 22
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4. LCF behaviour of high strength aluminium alloys AA 6110A and AA 6086Jernej Klemenc, Srečko Glodež, Matej Steinacher, Franc Zupanič, 2023, izvirni znanstveni članek Opis: The proposed research presents the comprehensive investigation of the Low Cycle Fatigue (LCF) behaviour of two high-strength aluminium alloys of series AA 6xxx: the conventional alloy AA 6110A and the newly developed alloy AA 6086. Both alloys were characterised in the as-cast condition after homogenisation, extrusion, and T6 heat treatment.
The quasi-static strength and hardness of the aluminium alloy AA 6086 were found to be significantly higher if compared to the AA 6110A alloys, while the ductility was a little bit smaller. The LCF tests showed that the AA 6086 alloy is more suitable for the high-cycle fatigue regime. On the other hand, the engineering advantage of the AA 6110A alloy is only for low-cycle fatigue applications if less than 100 loading cycles are expected in the service life of the analysed structure. The fatigue cracks formed predominantly on the α-AlMnSi intermetallic particles in both alloys, and, during LCF tests, exhibited small crack propagation. The area of the fatigue crack growth was much smaller than the area of the forced fracture. At smaller amplitude strains the fatigue striations were present at the fracture surface, while, at higher amplitude strains, they were not present. The obtained experimental results represent a good basis for engineering design applications of the analysed alloys AA 6086 and AA 6110A.
Ključne besede: aluminijeve zlitine, malociklično utrujanje, eksperimentalno testiranje, fraktografija, aluminium alloys, low cycle fatigue, experimental testing, fractography
Objavljeno v DKUM: 29.03.2024; Ogledov: 197; Prenosov: 13
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5. Comprehensive analysis of different coating materials on the POM substrateTonica Bončina, Srečko Glodež, Brigita Polanec, Lara Hočuršćak, Franc Zupanič, 2023, izvirni znanstveni članek Opis: This study presents a comprehensive analysis of different coating materials on the POM substrate. Specifically, it investigated physical vapour deposition (PVD) coatings of aluminium (Al), chromium (Cr), and chromium nitride (CrN) of three various thicknesses. The deposition of Al was accomplished through a three-step process, particularly plasma activation, metallisation of Al by magnetron sputtering, and plasma polymerisation. The deposition of Cr was attained using the magnetron sputtering technique in a single step. For the deposition of CrN, a two-step process was employed. The first step involved the metallisation of Cr using magnetron sputtering, while the second step involved the vapour deposition of CrN, obtained through the reactive metallisation of Cr and nitrogen using magnetron sputtering. The focus of the research was to conduct comprehensive indentation tests to obtain the surface hardness of the analysed multilayer coatings, SEM analyses to examine surface morphology, and thorough adhesion analyses between the POM substrate and the appropriate PVD coating.
Ključne besede: POM, PVD coating, metal coating, adhesion analyses, indentation tests
Objavljeno v DKUM: 15.02.2024; Ogledov: 304; Prenosov: 37
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6. Melting point of dried gold nanoparticles prepared with ultrasonic spray pyrolysis and lyophilisationŽiga Jelen, Marcin Krajewski, Franc Zupanič, Peter Majerič, Tilen Švarc, Ivan Anžel, Jernej Ekar, Sz-Chian Liou, Jerzy Kubacki, Mateusz Tokarczyk, Rebeka Rudolf, 2023, izvirni znanstveni članek Opis: A coupled process of ultrasonic spray pyrolysis and lyophilisation was used for the synthesis of dried gold nanoparticles. Two methods were applied for determining their melting temperature: uniaxial microcompression and differential scanning calorimetry (DSC) analysis. Uniaxial microcompression resulted in sintering of the dried gold nanoparticles at room temperature with an activation energy of 26–32.5 J/g, which made it impossible to evaluate their melting point. Using DSC, the melting point of the dried gold nanoparticles was measured to be around 1064.3°C, which is close to pure gold. The reason for the absence of a melting point depression in dried gold nanoparticles was their exothermic sintering between 712 and 908.1°C.
Ključne besede: gold nanoparticles, melting point, ultrasonic spray pyrolysis, characterisation
Objavljeno v DKUM: 08.12.2023; Ogledov: 448; Prenosov: 30
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7. Wear Behaviour of Multilayer Al-PVD-Coated Polymer GearsTonica Bončina, Brigita Polanec, Franc Zupanič, Srečko Glodež, 2022, izvirni znanstveni članek Opis: A comprehensive experimental investigation of the wear behaviour of coated spur polymer gears made of POM is performed in this study. Three different thicknesses of aluminium (Al) coatings were investigated and deposited by the Physical Vapour Deposition (PVD) process. The Al coating was deposited in three steps: By plasma activation, metallisation of the aluminium by the magnetron sputtering process, and plasma polymerisation. The wear of the gears was tested on an in-house developed testing rig for different torques (16, 20, and 24 Nm) and a rotational speed of 1000 rpm. The duration of the experiments was set to 13 h, when the tooth thickness and, consequently, the wear of the tooth flank were recorded. The experimental results showed that the influence of metallisation with aluminium surface coatings on the wear behaviour of the analysed polymer gear is not significantly important. The results also showed that the gears with a thicker aluminium coating showed greater wear than gears with a thinner coating or even without a coating. This is probably due to the fact that the aluminium particles that started to deviate during gear operation represented the abrasive material, which led to the faster wear of the contacting surfaces of the meshing gear flanks.
Ključne besede: polymer gears, aluminium PVD coating, Physical Vapour Deposition process, multilayer coating, wear
Objavljeno v DKUM: 15.11.2022; Ogledov: 580; Prenosov: 79
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8. Numerična simulacija odrezavanja gredic : magistrsko deloGorazd Fortin, 2022, magistrsko delo Opis: Za potrebe naročila podjetja SIJ Ravne Systems je bilo treba skonstruirati škarje za rezanje gredic v vročem in pripadajoči valjčni progi. Od tega je naš del obsegal konstrukcijo sestavov noža, ki sta bila koncipirana in snovana po delih in razdelana v razdelavi. Pripravljeni so bili materialni modeli uporabljenih materialov, izvedeni sta bili termična in eksplicitna simulacija za validacijo konstrukcije sestavov noža in poleg ostalih rezultatov so bile pri tem pridobljene največje sile, ki delujejo na škarje v procesu rezanja. Pripravljene so bile tudi sestavne in delavniške risbe delov sestavov noža in v zaključku, po razmisleku glede na izpolnjevanje zahtev zahtevnikov, je bila ugotovljena ustreznost konstrukcije sestavov noža in rezultatov simulacij.
Ključne besede: rezanje v vročem, gredica, škarje, sestav noža, materialni model, konstruiranje, termična simulacija, eksplicitna simulacija
Objavljeno v DKUM: 27.09.2022; Ogledov: 734; Prenosov: 65
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9. Konstrukcijski materiali : učbenikIvan Anžel, Mihael Brunčko, 2022, učbenik za višje in visoke šole Opis: Učbenik je kot osnovna literatura namenjen študentom 1. stopnje študijskih programov Strojništvo, Gospodarsko inženirstvo in Mehatronika. Učbenik sestavljajo tri samostojna poglavja, ki kot celota prinašajo znanja s področja materialov in tehnologij in so potrebna pri razvoju, raziskavah in uporabi materialov na področju strojništva, elektrotehnike, avtomatike, energetike ... Prvo poglavje obravnava značilne skupine konstrukcijskih materialov in njihovo zgradbo. Opisani so osnovni pojmi in predstave o materialih, ki so potrebne za razumevanje njihovih lastnosti. V drugem poglavju so obravnavane ključne lastnosti konstrukcijskih materialov, ki omogočajo uspešno izbiro materialov za določeno aplikacijo. Tretje poglavje vsebuje izbrane primere konstrukcijskih materialov. Opisuje posebna jekla za uporabo v strojništvu, lahke zlitine, konstrukcijsko keramiko, keramična stekla in polimerne materiale.
Ključne besede: konstrukcijski materiali, posebna jekla, lahke zlitine, inženirska keramika in stekla, polimerni materiali
Objavljeno v DKUM: 23.02.2022; Ogledov: 1528; Prenosov: 290
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10. Simulation of Dual-Beam Laser Metal Deposition : magistrsko deloMatej Kočevar, 2021, magistrsko delo Opis: Laser metal deposition process plays an important role in the coating and additive manufacturing of the components. Implementation of dual-beam process represents a further development and offers the advantage of laser ablation process, which provides exert force on the melt pool and increases absorption properties of the workpiece for laser light in comparison to conventional laser metal deposition processes.
The main goal of the present work is to predict temperature distribution on the surface and in the cross-section during a dual-beam laser metal deposition. A better understanding of temperature distribution of the dual-beam laser metal deposition is crucial for analyzing the impact of different process parameters on the process. The prediction of temperature distribution was done using the version 6.14-6 of finite element software ABAQUS/Standard from Dassault Systèmes. The results of the simulations show that the temperature distribution in the case of dual-beam laser metal deposition can be determined with minimum deviation by utilizing the finite element analysis.
Ključne besede: Laser Metal Deposition (LMD), dual-beam process, wire-based Laser Metal Deposition (LMD-w), Finite Element Method (FEM)
Objavljeno v DKUM: 23.09.2021; Ogledov: 1214; Prenosov: 71
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