1. Sodobni inženirski materialiIvan Anžel, Franc Zupanič, Mihael Brunčko, 2025, drugo učno gradivo Opis: Skripta, Sodobni inženirski materiali je kot temeljno študijsko gradivo namenjeno pervenstveno študentom 2. stopnje študijskih programov Strojništva, Gospodarskega inženirstva, Mehatronike in študentom Inženirsko oblikovanja izdelkov. Skripta je sestavljena iz treh poglavij: (i) Zgradba in izbira inženirskih materialov; (ii) Lastnosti inženirskih materialov; (iii) Primeri sodobnih inženirskih materialov. V prvem poglavju je obravnavana zgradba kovinskih, keramičnih, polimernih in kompozitnih materialov ter predstavljeni so kriteriji, ki omogočajo inženirjem glede na želeno kombinacijo lastnosti materialov, njihovo ustrezno izbiro za določeno aplikacijo. Drugo poglavje obravnava lastnosti sodobnih inženirskih materialov s poudarkom na poglobljenem študiju razlage korelacij med zgradbo, mikrostrukturo in lastnostmi. V zadnjem najobsežnejšem poglavju so predstavljeni izbrani primeri sodobnih inženirskih materialov, katerih uporaba e v industrijski praksi dandanes zelo aktualna. Če naštejemo samo najbolj zanimive: disperzijsko utrjeni materiali, spominske zlitine, konstrukcijska keramika, materiali za shranjevanje vodika, hitrostrjeni kovinski materiali, sodobne aluminijeve zlitine, biopolimeri in še mnogi drugi.
Ključne besede: sodobni inženirski materiali, zgradba, izbira materialov, mikrostruktura, lastnosti
Objavljeno v DKUM: 27.02.2025; Ogledov: 0; Prenosov: 749
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2. The characterization of phase transformations in rapidly solidified Al-Fe and Cu-Fe alloys through measurements of the electrical resistance and DSCMilan Bizjak, Ladislav Kosec, Borut Kosec, Ivan Anžel, 2006, izvirni znanstveni članek Opis: For the characterization of the phase transformations in the alloys during the heat treatment the various methods of the thermal analyses are available. Thermogravimetry, differential thermal analysis (DTA) and the differential scanning calorimetry (DSC) are the most frequently used methods. The phase transformations proceed in two stages, i.e. nucleation and the growth of the new phase. Both processes are closely linked with the movement of the atoms. Rapidly solidified alloys often contain the elements with the low diffusivity. During the transition from the unstable to the stable state the energy changes are small, therefore the characterization of the changes by DTA, DSC is very difficult and could not be measured. During the heat treatment the phase transformations of the rapidly solidified alloys of Al-Fe and Cu-Fe were successfully detected by the simultaneous measurements of the electrical resistance, and were compared by the DSC method. By determination of the temperature regions of the phase transitions or temperatures, where the dynamics of the changes is maximal, the samples were heat treated and analysed by the scanning and transmission electron microscopy respectively.
Ključne besede: rapidly solidified Al-Fe alloy, rapidly solidified Cu-Fe alloy, transformations, electrical resistance, differential scanning calorimetry
Objavljeno v DKUM: 03.07.2017; Ogledov: 1966; Prenosov: 149
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3. Synthesis and characterization of hardened Cu-Fe-Ni-P alloyGoran Brovč, Goran Dražić, Blaž Karpe, Igor Đorđević, Gorazd Lojen, Borut Kosec, Milan Bizjak, 2015, izvirni znanstveni članek Opis: In the manufacturing industry of electrical contacts, the prohibition of the use of toxic metals (Cd, Be), and desire to avoid the alloying with precious metals (Ag) has created a need for new alloys with good electrical conductivity and high mechanical properties at elevated temperatures. As a potentially useful material for this purpose, we have analyzed the continuously cast Cu-Fe-Ni-P alloy in various heat treatment conditions. Sequence of phase transformations during heat treatment was followed by 4 point D.C. electrical resistivity measuring method, and analyzed by scanning (SEM) and transmission (TEM) electron microscopy. Measurements of Vickers hardness and electrical conductivity after various heat treatment procedures indicate on high potential of Cu-Fe-Ni-P alloys as a material for electrical contacts.
Ključne besede: copper alloys, precipitation hardening, electrical contacts, electrical conductivity
Objavljeno v DKUM: 03.07.2017; Ogledov: 2320; Prenosov: 97
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4. Rhodium platings : experimental studyRebeka Rudolf, Bojan Budić, Dragoslav Stamenković, Miodrag Čolić, Andrej Ivanič, Borut Kosec, 2013, drugi znanstveni članki Opis: Modern rhodium plating solutions are based on either sulphate or phosphate. Although in theory there are four possible combinations, in practice only three different rhodium electrolytes are used. These are based on dilutions of rhodium sulphate or phosphate concentrates with added sulphuric or phosphoric acid. These processes are be discussed in this paper with a demonstration of Rh platings in the Slovenian firm Zlatarna Celje d.d.
Ključne besede: rhodium, plating, jewellery, properties
Objavljeno v DKUM: 03.07.2017; Ogledov: 1194; Prenosov: 115
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5. Microstructure of NiTi orthodontic wires observations using transmission electron microscopyJanko Ferčec, Darja Feizpour, Borut Buchmeister, Franc Rojko, Bojan Budič, Borut Kosec, Rebeka Rudolf, 2014, izvirni znanstveni članek Opis: This work presents the results of the microstructure observation of six different types of NiTi orthodontic wires by using Transmission Electron Microscopy (TEM). Within these analyses the chemical compositions of each wire were observed in different places by applying the EDS detector. Namely, the chemical composition in the orthodontic wires is very important because it shows the dependence between the phase temperatures and mechanical properties. Micro- structure observations showed that orthodontic wires consist of nano-sized grains containing precipitates of Ti2Ni and/or TiC. The first precipitated Ti2Ni are rich in Ti, while the precipitated TiC is rich in C. Further investigation showed that there was a difference in average grain size in the NiTi matrix. The sizes of grains in orthodontic wires are in the range from approximately 50 to 160 nm and the sizes of precipitate are in the range from 0,3 μm to 5 μm.
Ključne besede: orthodontic wires, nickel-titanium orthodontic wire, NiTi wire, shape memory alloys, SMA wires, microstructure, transmission electron microscopy, TEM, average grain size
Objavljeno v DKUM: 03.07.2017; Ogledov: 1524; Prenosov: 127
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6. Mechanical properties and microstructure characterisation of Au-Pt dental alloyRebeka Rudolf, Tjaša Zupančič Hartner, Ladislav Kosec, Aleksandar Todorović, Borut Kosec, Ivan Anžel, 2008, izvirni znanstveni članek Opis: Development of a dental alloy with high Au content is based on the ternary system of Au-Pt-Zn with a nominal composition of 86,9Au-9,9Pt-1,5Zn, and about 1,5 wt.% micro-alloying elements (In, Ir, Rh). The results analyses of different heat-treated states showed that the optimal mechanical properties and hardness of an Au-Pt-Zn alloy can be reached with combinations of heat treatment for 20 minutes at 723 K and then slowly cooling, if the alloy was annealed at 1223 K for 30 minutes and the water quenched. Research results confirmed that the microstructure of the Au-Pt-Zn alloy consists of two phases: α1-phase rich in Au (main phase) and α2-phase rich in Pt (minor phase). During XRD analysis and use of the Rietveld method, it was found that the α1-phase content is about 98,5 wt.% while the content of α2-phase is 1,5 wt.%. STA analyses show that the Au-Pt-Zn alloy has a solidus temperature of about 1292 K and a liquidus temperature of about 1412 K.
Ključne besede: Au dental alloy, properties, microstructure, characterization
Objavljeno v DKUM: 03.07.2017; Ogledov: 1326; Prenosov: 128
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7. Internal oxidation of silver alloys with tellurium, selenium and sulphurGorazd Kosec, Ladislav Kosec, Ivan Anžel, Vasilij Gontarev, Borut Kosec, Milan Bizjak, 2005, izvirni znanstveni članek Opis: Silver alloys with tellurium, selenium and sulphur fulfil the conditions for the internal oxidation. Microstructure of these alloys consists of matrix (dilute solid solution) and particles of intermetallic compounds. Internal oxidation of ternary alloys is very similar to that of the binary alloys, but there are also distinctions in thermodynamics properties of alloying elements.
At the direct oxidation of the particles of the intermetallic compound the phenomena of the selective oxidation was observed. Concentration of more reactive elements is increasing in the oxidized part of the particles of the intermetallic compound (Te in AgTeSe alloys). Therefore the precipitated oxides formed with diffusional internal oxidation are richer with less reactive alloying element (Se in AgTeSe alloy). In the precipitated oxide particles the concentration of selenium is more than twice higher than of tellurium.
Ključne besede: internal oxidation, silver, alloys, compound, particle
Objavljeno v DKUM: 03.07.2017; Ogledov: 1135; Prenosov: 103
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8. Analysis of interface at explosive welded plates from low-carbon steel and titaniumBorut Kosec, Ladislav Kosec, Gabrijela Čevnik, Peter Fajfar, Mirko Gojić, Ivan Anžel, 2004, izvirni znanstveni članek Opis: On the basis of experimentally obtained data, it was established that a very thin layer of a melt is generated at the explosive welding of two metals at the bond interface within which impurities flow at the bond during melting. Rapid cooling after the collision generates an alloy of different structure and very small grains of an average thickness app. 1 to 2 micro m. The generation of such an amorphous layer in the bond area has been noticed with various metal combinations and represents a fundamental mechanism of explosive welding of metals. Using the metallographic analysis, the development of the vortices which were formed by the explosive welding of low-carbon steel and titanium plates is described in the paper.
Ključne besede: metallurgy, explosion welding, plates, composites, low-carbon steel, titanium, melt, vortex
Objavljeno v DKUM: 03.07.2017; Ogledov: 1400; Prenosov: 84
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9. Analysis of a strain rate field in cold formed material using the visioplasticity methodLeo Gusel, Rebeka Rudolf, Borut Kosec, 2009, drugi znanstveni članki Opis: In this paper the visioplasticity method is used to find the complete velocity and strain rate distributions from the experimental data, using the finite-difference method. The data about values of strain rates in plastic re- gion of the material is very important for calculating stresses and the prediction of product quality. Specimens of copper alloy were extruded with different lubricants and different coefficients of friction and then the strain rate distributions were analysed and compared. Significant differences in velocity and strain rate distributions were obtained in some regions at the exit of the deformed zone.
Ključne besede: forward extrusion, copper alloy, visioplasticity, strain rate, lubrication
Objavljeno v DKUM: 03.07.2017; Ogledov: 966; Prenosov: 144
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10. Microstructural and phase analysis of CuAlNi shape-memory alloy after continuous castingMirko Gojić, Stjepan Kožuh, Ivan Anžel, Gorazd Lojen, Ivana Ivanić, Borut Kosec, 2013, izvirni znanstveni članek Opis: The results of the characterization of a CuAlNi shape-memory alloy after continuous casting technology are shown. Using this procedure a bar with a diameter of 8 mm was manufactured. After solidification of the alloy the microstructure characterization was carried out using optic microscopy (OM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) methods. Our results showed that the as-cast alloy consisted of the parent β1 and β1’ martensite phases. The martensite phase primary as the needle-like inside grains was observed. Martensite laths have different orientations inside particular grains. It was found that the average grains size is 98.78 µm. The grain diameter near to the external surface is higher than in the center. The average hardness of the alloy was 275 HV1.
Ključne besede: shape memory alloys, martensite, continuous casting, grain size
Objavljeno v DKUM: 16.03.2017; Ogledov: 1237; Prenosov: 125
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