1. Wear Behaviour of Multilayer Al-PVD-Coated Polymer GearsTonica Bončina, Brigita Polanec, Franc Zupanič, Srečko Glodež, 2022, original scientific article Keywords: polymer gears, aluminium PVD coating, Physical Vapour Deposition process, multilayer coating, wear
Published in DKUM: 15.11.2022; Views: 186; Downloads: 18
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2. VPLIV NIKLJA NA LASTNOSTI ALUMINIJEVIH BRONOV : diplomsko deloDenis Arnšek, 2019, undergraduate thesis Abstract: V diplomskem delu sem se ukvarjal s študijem vpliva različnega deleža niklja na mikrostrukturo in s tem na mehanske lastnosti aluminijevih bronov. Ugotovil in uporabil sem ustrezne metode metalografske priprave vzorcev iz brona in načine kvalitativne in kvantitativne metalografske analize. Določil sem vrste mikrostrukturnih sestavin in delež β-faze. Izvedli smo natezne preskuse pri sobni in povišani temperaturi, udarne preizkuse in meritve trdote. Ugotovil sem povezavo med deležem niklja in trdoto, ter povezavo z drugimi trdnostnimi lastnostmi (natezno trdnostjo in udarno žilavostjo pri sobni ter pri povišani temperaturi).
Keywords: Aluminijevi broni, metalografska analiza, mehanske lastnosti, delež niklja, delež β-faze
Published in DKUM: 07.05.2019; Views: 932; Downloads: 86
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3. Effect of cooling rate on the microstructure of an Al94Mn2Be2Cu2 alloyTonica Bončina, Boštjan Markoli, Franc Zupanič, 2012, original scientific article Abstract: In this study the effect of the cooling rate on the microstructure of Al94 Mn2 Be2 Cu2 alloy was investigated. The vacuum induction melted and cast alloy was exposed to different cooling rates. The slowest cooling rate was achieved by the DSC (10 K·min^−1), the moderate cooling rate succeeded by casting in the copper mould (≈1 000 K·s−1) and the rapid solidification was performed by melt spinning (up to 10^6 K·s^−1). The microstructure of the DSC-sample consisted of α-Al matrix, and several intermetallics: τ1-Al29 Mn6 Cu4 , Al4 Mn, θ-Al2 Cu and Be4 Al(Mn,Cu). The microstructures of the alloy at moderate and rapid cooling consisted of the α-Al matrix, i-phase and θ-Al2 Cu. Particles of i-phase and θ-Al2 Cu were much smaller and more uniformly distributed in melt-spun ribbons.
Keywords: Al-alloy, metallography, microstructure, cooling rate, solidification
Published in DKUM: 03.07.2017; Views: 721; Downloads: 90
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4. In situ TEM study of precipitation in a quasicrystal-strengthened Al-alloyTonica Bončina, Franc Zupanič, 2017, original scientific article Abstract: Precipitation kinetics and mechanisms within an Al-Mn-Be-Cu quasicrystal strengthened alloy at 300°C were studied using in-situ transmission electron microscopy. The alloy was cast into a copper mould. Quasicrystalline precipitates formed throughout
the Al-rich solid solution, whilst heterogeneous formations of Al2Cu and T-phase occurred on icosahedral quasicrystalline particles formed during solidification. The formation of quasicrystalline particles and T-phase was limited by manganese diffusivity, whilst
that of Al2Cu by copper diffusivity. The precipitation produced only a small hardening effect.
Keywords: Al-alloy, quasicrystal
Published in DKUM: 09.05.2017; Views: 1119; Downloads: 328
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5. The action of a laser on an aluminium targetVišnja Henč-Bartolič, Tonica Bončina, Suzana Jakovljević, Davor Pipić, Franc Zupanič, 2008, original scientific article Abstract: A nitrogen laser beam (337 nm, 6 ns (FWHM), (3.2 [plus minus] 0.2) mJ) was focused with a quartz lens (f = 100 mm) onto an aluminium target in air at normal pressure. The laser irradiation and plasma explosion caused a modification to the Al surface and the deposition of a thin film (droplets) onto a glassy carbon plate. The irradiated target and the deposited material were studied with a scanning electron microscope (SEM) and a focused-ion-beam (FIB) device. A crater surrounded by a rim was produced on the spot of maximum irradiation on the aluminium target. The crater, very deep in comparison to its width and thickness, was presumably caused by the Kelvin-Helmholtz and the Rayleigh-Taylor instabilities. The temperatures of the electron and the massive particles were explained.
Keywords: aluminium, laser ablation, thin film deposition, instabilities, temperatures
Published in DKUM: 23.03.2017; Views: 1082; Downloads: 104
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8. Mikrostruktura hitro strjenih trakov zlitine Cu-ZrIvan Anžel, Alojz Križman, Tonica Bončina, Franc Zupanič, Gorazd Lojen, L. Kosec, Borivoj Šuštaršič, 1995, original scientific article Abstract: Hitro strjene trakove zlitin Cu -0,5% Zr in Cu - 1% Zr smo izdelali s postopkom litja taline na hitro se vrteči boben pri različnih procesnih parametrih. Mikrostrukturo trakov smo raziskali v odvisnosti od debeline oziroma povprečne ohlajevalne hitrosti in od sestave zlitin. V prečnem prerezuje mikrostruktura tankih trakov (50-55▫$mu$▫m) sestavljena iz cone transkristalnih zrn, ki sega do zgornje proste površine in v kateri ločimo tri področja z različno substrukturo: področje brez mikrosegregacij, področje trakaste substrukture in področje s celično/dendritno substrukturo. Trakovi z debelino 85-90▫$mu$▫m vsebujejo v prečnem prerezu poleg transkristalne cone še cono globularnih zrn z dendritno morfologijo. Velikost posamezne cone ter substrukturnih področij znotraj transkristalne cone je pri isti debelini trakov odvisna od kemijske sestave zlitin.
Keywords: hitro strjevanje, mikrostruktura, trakovi, Cu - Zr zlitina
Published in DKUM: 10.07.2015; Views: 1216; Downloads: 51
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9. Struktura in mikrostruktura jeklenih peskov, narejenih v Abrasivu MutaRebeka Rudolf, Alojz Križman, Tonica Bončina, 1999, professional article Abstract: V Sloveniji je podjetje Abrasiv Muta edini proizvajalec jeklenih peskov. Njihovi konkurenti so svetovne multinacionalke, eden izmed njih je tudi Whelebrator Alleward France. V članku podajamo primerjavo mikrostruktur vzorcev jeklenih peskov Abraziva Mute z vzorci tega konkurenčnega podjetja. Poameriškem standardu SAE J827 smo pripravili in analizirali vzorce peskov ter ocenili napake na prerezih delcev. Raziskave so obsegale makroskopski in mikroskopski pregled vzorcev. Naredili smo tudi meritve trdot, preskuse obrabne obstojnosti in sejalno analizo teh peskov. Na podlagi rezultatov smo ugotovili, da so peski podjetja Abraziv Muta in francoskega podjetja primerljivi glede kvalitete in mikrostrukturnih značilnosti, medtem ko imajo peski romunskega podjeja veliko slabše lastnosti.
Keywords: jekleni pesek, mikrostruktura, napake
Published in DKUM: 10.07.2015; Views: 1713; Downloads: 51
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10. Vpliv razmer pri razprševanju taline na lastnosti jeklenega granulataFranc Zupanič, Tonica Bončina, Alojz Križman, Rebeka Rudolf, 1999, professional article Abstract: V tej raziskavi smo opredelili vpliv procesnih parametrov pri razprševanju jeklene taline na lastnosti visokoogljičnega jeklenega granulata. V sodelovanju s podjetjem Abrasiv Muta smo v industrijskih razmerah razpršili devet šarž jeklene taline ob znanih vrednostih različnih vplivnih parametrov, kot so temperatura in pretok taline, tlak in temperatura razpršilne vode, temperatura in nivo vode v hladilnem bazenu... Rezultati preiskav jeklenega granulata so pokazali, da ima najizrazitejši vpliv tlak razpršilne vode, ki določa velikostno porazdelitev jeklenih kroglic v granulatu, njihovo okroglost ter obrabno obstojnost. Tudi vpliv drugih dejavnikov ni zanemarljiv. Ugotovljeno je, da večje granulacije kroglic vsebujejo večje število napak kot drobne, to pa se kaže tudi v njihovi manjši obrabni sposobnosti.
Keywords: jekleni granulat, velikostna porazdelitev, okroglost, obrabna obstojnost, Ervinov preskus
Published in DKUM: 10.07.2015; Views: 861; Downloads: 38
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