20.500.12556/RUL-103336 Mikrotrdota v zvarnih spojih raznorodnih visokotrdnostnih aluminijevih zlitin Microhardness in Dissimilar High-Strength Aluminium Alloy Welds V zaključni nalogi smo obravnavali mehanske lastnosti aluminijevih zlitin za gnetenje za uporabo v transportni industriji. Osredotočili smo se na trdnostne lastnosti, pridobljene po postopku varjenja s trenjem in mešanjem. V eksperimentalnem delu smo za zvarni spoj zlitine 2017A-T451 in 7075-T651, varjene pod različnimi pogoji, izvedli meritve hrapavosti in valovitosti ter izmerili mikrotrdoto v preseku zvarnega mesta. Nato smo poiskali povezave med izmerjenimi vrednostmi in varilnimi parametri. Izbrani vzorec smo pogledali pod mikroskopom ter opravili makro-in mikrostrukturno analizo. Najdene ekstremne vrednosti mikrotrdote smo na koncu primerjali s proučevanimi mikrostrukturnimi značilnostmi. Meritve hrapavosti so pokazale, da se nahaja največji aritmetični odstopek profila v smeri potovanja orodja, in sicer ob pogoju podajanja na obrat 25 vrt/cm pri vrednosti 5,4 µm. Najvišje vrednosti trdote so bile izmerjene pri vzorec s podajanjem na obrat 16 vrt/cm v zgornjem delu zvara v coni mešanja, in sicer pri okoli 170 HV0,2, medtem ko je bila najnižje izmerjena trdota pri istem vzorcu v spodnjem delu zvara v toplotno vplivanemu področju, in sicer na strani zvara z zlitino 7075 v vrednosti 96 HV0,2. In this study we investigated the mechanical properties of wrought aluminium alloys for transportation industry use. We focused on the strength properties, obtained by the friction stir welding process. In the experimental part, we took measurements of surface roughness and waveviness of friction stir welded joints in 2017A-4 and 7075-T6 aluminium alloys that were welded using different welding parameters. We also measured the microhardness profile through the transverse cross-section of butt joints. After finding the correlation between measured values and the welding process parameters, macroscopic and microscopic analyses for the chosen specimen were performed. Then we investigate the possible correlation between measured microhardness extremes and microstructure properties. The topography analysis showed us that the highest value of mean roughness (5,4 µm) was observed in the direction parallel to the welding direction in the area where welding process at a feed per revolution of 25 rev/cm took place. The maxima of microhardness were observed at the upper layer of the welding sample that was welded at a feed per revolution of 16 rev/cm with a value of 170 HV0,2. In the lower layer of the same specimen, the minimum of 96 HV0,2 was measured. mikrotrdota visokotrdnostne aluminijeve zlitine varjenje s trenjem in mešanjem topografija mikrostruktura makrostruktura Microhardness High-strength aluminium alloys Friction stir welding Topography Microstructure Macrostructure true false false [U. Margon ] Slovenski jezik Angleški jezik Zaključna naloga 2018-09-16 07:46:03 2018-09-16 07:46:04 2023-10-13 08:43:33 0000-00-00 00:00:00 2018 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 539.4.01+620.179.2(043.2) 208844 16235035 2632.pdf 2632.pdf 1 351556AD63C16FDAD3D362DBA107BA91 904ad45275978117830cb27b77cf1c0a52f25d1a2ff600c92dbc6ffbc9754422 c77e61c3-a1b5-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=113753 Fakulteta za strojništvo 0 0 0