20.500.12556/DKUM-89776 Vpliv mikrolegiranja s kemijskimi elementi Sc, Y in V na mikrostrukturo in lastnosti zlitine Al-Mg-Si doktorska disertacija Effect of chemical elements Sc, Y and V on microstructure and properties of Al-Mg-Si alloy V disertaciji je obravnavan vpliv mikrolegiranja s Sc, Y in V na razvoj kompleksne mikrostrukture in izboljšanja lastnosti. Referenčno zlitino predstavlja AA 6086, ki je modificirana zlitina AA 6082 z višjimi vsebnostmi Si, Cu in Zr. Preiskovani vzorci so bili liti v bakreno koliko ter toplotno obdelani v različnih temperaturnih režimih. Karakterizacija je potekala z uporabo matematičnih modelov ter eksperimentalno s svetlobno mikroskopijo, vrstično in presevno elektronsko mikroskopijo, energijsko disperzijsko spektroskopijo, rentgensko difrakcijo, diferenčno vrstično kalorimetrijo ter meritvami mehanskih lastnosti v obliki dilatometrije, trdote in tlačnih preizkusov. Izvedena je bila napredna karakterizacija mikrostrukturnih vsebin v litem in homogeniziranem stanju, ter v umetno staranih stanjih v temperaturnem območju od 170 °C do 450 °C. Razvoj mikrostrukture in lastnosti je primerljiv za zlitine s Sc in kombinacijo Sc in Y, medtem ko dodatek V bistveno ne vpliva na spremembe v referenčni zlitini. V vseh vzorcih so potrjeni številni eksotermni procesi, ki nakazujejo na aktiven razvoj disperzoidov in izločkov. Elementa Sc in Y vplivata na kinetiko izločanja predvsem pri povišanih temperaturah, kjer se reakcija nastajanja disperzoidov v primerjavi z referenčno zlitino premakne za red velikosti 50 °C. V vzorcih so detektirani majhni poligonalni in večji igličasti disperzoidi, za vzorca s Sc in Y pa je opravljena poglobljena karakterizacija prisotnih disperzoidov. Izboljšane mehanske lastnosti referenčne zlitine so bile dosežene s toplotno obdelavo vzorcev v litem stanju, kjer so izmerjene vrednosti v povprečju 77,5 HV ter so 30 % višje kakor v toplotno obdelanih homogeniziranih vzorcih. Visokotrdnostne lastnosti so bile dosežene s klasičnim staranjem pri 180 °C, kjer je povprečna izmera trdota po 8 urah znašala 122 HV. This thesis discusses the influence of Sc, Y and V microalloying on the development of complex microstructure and mechanical properties. The reference alloy is AA 6086, which is a modified AA 6082 alloy with higher Si, Cu and Zr contents. Investigated samples were cast in a copper mold and heat treated in different temperature regimes. Characterisation was carried out using mathematical models and experimentally by light microscopy, scaning and transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, differential scanning calorimetry and mechanical property measurements in the form of dilatometry, hardness and compression tests. Advanced characterisation of the microstructural components in the cast, homogenised and artificially aged condition has been carried out in the temperature range 170 °C to 450 °C. The microstructural and property evolution is comparable for alloys with Sc and Sc-Y, while the addition of V does not significantly affect on properties of reference alloy. In all samples, a number of exothermic processes are confirmed, indicating the active development of dispersoids and precipitates. The Sc and Y elements influence on kinetics of precipitation mainly at elevated temperatures, where the dispersoid formation shifts for 50 °C compared to the reference alloy. Small polygonal and larger spheroidal dispersoids are detected in the samples, and an in-depth characterisation of the dispersoids present is performed for the Sc and Y samples. Improved mechanical properties of the reference alloy were achieved by heat treatment of the cast samples, where the measured values are on average 77,5 HV and 30 % higher than in the heat-treated homogenised samples. High strength properties were achieved by classical ageing at 180 °C, where the average hardness measured after 8 hours was 122 HV. aluminijeve zlitine Al-Mg-Si mikrolegiranje mikrostruktura mehanske lastnosti Aluminium alloy Al-Mg-Si microalloying microstructure mechanical properties true true false [S. Žist] Slovenski jezik Angleški jezik Doktorsko delo/naloga 2024-08-12 04:04:19 2025-05-12 12:09:18 2025-05-23 03:10:47 0000-00-00 00:00:00 2025 0 Maribor 0 Maribor XIV, 101 str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 2026-12-31 620.17/.18:669.715(043.3) 236805635 DOK_Zist_Sandi_2025.pdf DOK_Zist_Sandi_2025.pdf 1 ACA0DCCA8887230ADE58EAD473153262 4b869b45073071a6dca0a87e0c6efe5a6eefdccd18b6a9ea66b33cd2966d92ab 50892ca5-2f14-11f0-925b-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=190886 Fakulteta za strojništvo 0 0 0