6720 KB199 KB0 KB2014Anžel, IvanArtiček, UrošGusel, LeoVII, 107 str., 30 cmCOBISSID:18007830URN:URN:NBN:SI:doc-KOLTRBB1slU. Artičekvisokošolska delabakercopperDisertacijeDodajalne tehnologijefunctionally graded materialfunkcionalno gradientni materialiLENS technologyMaterialimehanske lastnostimicrostructuremikrostrukturaorodno jeklotehnologija LENStool steelRazvoj mikrostrukture pri izdelavi gradientnega materiala H13-Cu s tehnologijo LENS| doktorska disertacija|LENS technology represents a modern additive technology for the application of metallic materials. In this dissertation, the conceptual design of the use of high-tech materials is presented in tools for injection moulding as well as tools for die casting of light metals fabricated with this technology. In practice, deviations of dimensional and design tolerances of the product frequently occur during the solidification due to uneven temperature distribution in the tool and consequently, in the product during cooling. At the same time, thermal conductivity of tool steels limits the cooling time and consequently, the productivity of tools. The presented problem of synthesizing a H13 tool steel and copper alloy using functionally graded materials with specific microstructure and a combination of properties represents new possibilities for optimization in this field. The dissertation shows the influence of the layered deposition and thermal conditions of the LENS technology on the development of microstructure and consequently, mechanical properties. For easier understanding, we characterized reference samples of different chemical compositions using the traditional casting technology. Using various analyses, such as microstructural, chemical, thermal and phase, we determined phase compositions as well as the impact of technology on the formation of cracks and the development of microstructure, depending on the chemical composition and solidification conditions. In the field of chemical compositions which are susceptible to cracking, we examined the crack-filling mechanism, which is a result of complete wetting of copper and temperature conditions during the deposition of new layers. To examine the effects of phase compositions on mechanical properties of the alloys, tensile tests and microhardness measurements were carried out. Results show the possibility of a successful fabrication of samples of functionally graded materials H13-Cu using the LENS technology. Finally, the influence of solidification conditions on microstructure development as well as the model of microstructure development and stability are explainedTehnologija LENS predstavlja sodobno dodajalno tehnologijo nanašanja kovinskih materialov. Prikazana je idejna zasnova uporabe visokotehnoloških materialov v orodjih za brizganje umetnih mas ter orodjih za tlačno litje lahkih kovin in njihovih zlitin, izdelanih z omenjeno tehnologijo. V praksi se pogosto zgodi, da pride med strjevanjem do odstopanj dimenzijskih in oblikovnih toleranc izdelka zaradi neenakomerne porazdelitve temperature v orodju ter posledično v izdelku med ohlajanjem. Hkrati pa toplotna prevodnost orodnih jekel omejuje čas ohlajanja ter posledično produktivnost orodij. Obravnavana problematika sinteze zlitine orodnega jekla H13 in bakra v funkcionalno gradientnih materialih s specifično mikrostrukturo in kombinacijo lastnosti predstavlja nove možnosti optimizacije na tem področju. V disertaciji je predstavljen vpliv plastne gradnje in termičnih pogojev tehnologije LENS na razvoj mikrostrukture in posledično na mehanske lastnosti. Za boljše razumevanje zlitinskega sistema smo okarakterizirali referenčne vzorce, izdelane s tehnologijo litja, kjer smo se približali ravnotežnemu strjevanju. Z uporabo različnih analiznih metod smo določili fazne sestave ter vpliv tehnologije na tvorbo razpok in razvoj mikrostrukture v odvisnosti od kemijske sestave in razmer pri strjevanju. Na področju kemijskih sestav, ki so dovzetne za nastanek razpok, smo odkrili mehanizem zalitja razpok, ki je posledica popolnega močenja bakra in temperaturnih razmer pri nanosu novih plasti. Za razumevanje vpliva faznih sestav na mehanske lastnosti zlitin so bili izvedeni natezni preizkusi ter meritve mikrotrdot. Rezultati kažejo možnost uspešne izdelave vzorcev funkcionalno gradientnih materialov H13-Cu s tehnologijo LENS. Pojasnjen je vpliv pogojev strjevanja na razvoj mikrostrukture ter postavljen model razvoja in stabilnosti mikrostrukture v trdnemTEXTvisokošolska delatheses and dissertationsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Mariboru, Fakulteta za strojništvo