17168 KB212 KB0 KB2016Goričanec, DarkoGubeljak, NenadKrope, JurijMatavž, AlbinIX, 124 str., 30 cmCOBISSID:19765270URN:URN:NBN:SI:doc-LZAOHW47slA. Matavžvisokošolska delaageingBrusiDisertacijemechanical propertiesMehanske lastnostimicroscopic amalysis of grinding wheel samplesmikroskopska analiza vzorcev brusovnatezna trdnostresin-bonded wheelssmolno vezani brusistaranjestatistical methodsstatistične metodetensile strenghtVpliv staranja na mehanske lastnosti smolno vezanih brusov s korundnimi in SiC zrni| doktorska disertacija|The doctoral dissertation seeks to identify the manner in which ageing affects the mechanical and functional properties of resin-bonded grinding wheels with aluminium oxide and silicon carbide in certain time series based on the tests performed. The measurements provided the basis for the design of a temporal model of changes. The regularity of the approach used in the set research concept, which provided reliable and reproducible measurements, was confirmed with an assessment of the value of the Weibull modulus. Furthermore, the influence of humidity as the most likely cause for a steep downgrade in the mechanical properties of grinding wheels was examined and identified. Within that context, the system of forced, i.e. accelerated ageing of grinding wheels (additional humidification) was used under special atmospheric conditions. In the continuation, model mechanisms for changing microstructures during ageing were produced based on the microstructure characterization of grinding wheels that were exposed to different thermo mechanical impacts. These confirmed the most likely cause for ageing as established empirically and therewith related changes to the mechanical properties of grinding wheels. The findings were confirmed with a reversible thermal treatment process. Furthermore, the findings are useful in practice, i.e. in the process of manufacturing grinding wheels, allow for improvements to mechanical properties and, most of all, considerably slow down the ageing process, thus giving such products higher added valueV doktorski disertaciji smo na osnovi preizkusov, izvedenih na smolno vezanih brusih s korundnimi zrni in zrni silicijevega karbida (SiC), ugotavljali, kako v določenih časovnih zaporedjih staranje vpliva na njihove mehanske in funkcionalne lastnosti. Na osnovi meritev smo oblikovali časovni model poteka sprememb. Pravilnost pristopa zastavljenega koncepta raziskav, s katerim smo zagotovili zanesljivost in ponovljivost izvedenih meritev, smo potrdili z oceno vrednosti Weibullovega modula. Prav tako smo preverili in ugotavljali vpliv vlage kot najverjetnejšega povzročitelja hitrejšega padca mehanskih lastnosti brusov. V tem kontekstu smo uporabili sistem vsiljenega, t.j. hitrejšega staranja brusov (dodatno vlaženje) pri atmosferskih pogojih. V nadaljevanju smo na osnovi karakterizacije mikrostruktur brusov, ki so bili izpostavljeni različnim termomehanskim vplivom, izdelali modele mehanizmov spreminjanja mikrostruktur med staranjem. Ti so potrdili že empirično ugotovljen najverjetnejši razlog vpliva na staranje in s tem povezanih sprememb mehanskih lastnosti brusov. Ugotovitve smo z reverzibilnim procesom termične obdelave tudi potrdili. Spoznanja so praktično uporabna v procesu proizvodnje brusov, omogočajo izboljšanje mehanskih lastnosti, predvsem pa bistveno upočasnijo proces staranja in s tem dajo brusu višjo dodano vrednostTEXTvisokošolska delatheses and dissertationsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Mariboru, Fakulteta za kemijo in kemijsko tehnologijo