36 KB698 KB29 KB200020262011Jenko, MonikaKevorkijan, VaružanKovačec, UrošPaulin, IrenaŠkapin, Srečo D.letnik:45številka:6str. 537-544COBISSID:15665942ISSN:1580-2949URN:URN:NBN:SI:doc-SAXFJPJMenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijealuminijeve penekarakterizacijapanelipenilna sredstvavroče valjanjeModelling and preparation of core foamed Al panels with accumulative hot-roll bonded precursors| Načrtovanje in izdelava Al-panelov s sredico iz Al-pen na osnovi večstopenjsko toplo valjanih prekurzorjev|In this paper, laboratory and semi-industrial processes for the preparation of aluminium foam samples and core-foamed panels with closed porosity were investigated. The samples were prepared starting from the accumulative hot-roll bonded precursors, with titanium hydride (TiH2) or dolomite (Ca0.5Mg0.5CO3) powder added as the foaming agent. The formation of the precursors was performed in three steps. In the initial stage, titanium dihydride or dolomite particles were deposited on a single side of a selected number of aluminium strip samples made from the alloy AA 1050. In the second step, by putting together in pairs, single-sided coated strips, precursors with a two-layered structure were prepared. The samples were hot-rolled to a final thickness of 1.9-3.8 mm, introducing a total deformation of about 45-49 % by a process well-known as accumulative hot-roll bonding. In the third stage of the precursor's formation, the desired multilayered precursor's structure was achieved by hot-roll multi-passing, i.e., by repeating (with 2-16 passes) the accumulative hot-roll bonding procedure. The obtained precursors were foamed in an electrical furnace, under different foaming conditions, based on the initial temperature of the thermal decomposition of the foaming agent. The microstructure of the obtained foam samples was investigated with optical and scanning electron microscopy. According to the accumulated experimental results, one can conclude that the usage of dolomite powder as a foaming agent with a higher temperature of thermal decomposition (>750 °C) compared to TiH2, which thermally decomposed even at the temperatureof hot-rolling (>350 °C), enabling the formation of multilayered precursors at higher temperatures of hot-rolling without any intermediate annealing. This consequently increases the productivity of the foamed core panel production without influencing their final qualityV delu opisujemo razvoj laboratorijskih in polindustrijskih postopkov priprave vzorcev aluminijskih pen in panelov iz Al-pen z zaprto poroznostjo. Vzorce panelov smo izdelovali na osnovi večstopenjsko toplo valjanih prekurzorjev, ki so kot sredstvo za penjenje vsebovali delce titanovega dihidrida (TiH2) ali dolomitnega prahu (Ca0,5Mg0,5CO3). Postopek priprave večplastnih prekurzorjev je potekal v treh fazah. V začetni fazi smo delce titanovega dihidrida ali dolomita nanašali na izbrano stran aluminijevega traku zlitine AA 1050. Sledila je priprava dvoplastnega prekurzorja. Po dva in dva premazana trakova smo zložili tako, da sta se premazani stranici stikali ter dvojček vroče zvaljali na 1,9-3,8 mm s skupno deformacijo med 45-49%. Postopek smo v sklepni fazi izdelave prekurzorjev ponavljali do želene večplastnosti (od 2- do 16-krat ). S postopkom večkratnega valjanja in podvajanja plasti penilnega sredstva smo dosegli enakomerno porazdelitev penilnega sredstva skozi celoten prerez izdelanih prekurzorjev. Dobljene prekurzorje smo nato penili v električni peči pri različnih pogojih glede na temperaturo termičnega razkroja sredstva za penjenje. Mikrostrukturo dobljenih vzorcev pen smo analizirali z optično in vrstično elektronsko mikroskopijo. Z raziskavami smo potrdili, da uporaba dolomitnega prahu kot penilnega sredstva z višjo temperaturo termičnega razkroja (>750 °C) v primerjavi s TiH2, ki se termično razkraja že pri temperaturi toplega valjanja (>350 °C), omogoča izdelavo večplastnih prekurzorjev pri višjih temperaturah toplega valjanja brez vmesnega žarjenja in posledično povišuje produktivnosti brez vpliva na kakovost končnega izdelkaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije