Vpliv toplotnih obdelav na mehanske lastnosti aluminijeve zlitine EN AW-2011 : magistrsko delo

Smolar, Tinkara (author), Vončina, Maja (mentor), Steinacher, Matej (comentor)

Iztiskovanje, kot postopek preoblikovanja, predstavlja zgolj posamezni korak pri celotni metalurški verigi. Pri izločevalno-utrjevalnih zlitinah so tako ob deformaciji ključnega pomena tudi toplotne obdelave. Homogenizacija, ki se izvede pred postopkom iztiskovanja, in staranje, ki se izvede po postopku iztiskovanja, predstavljata ključen del raziskovalnega vprašanja v industrijski energetiki in ekonomiki. Optimiranje časovno in temperaturno ugodnejših toplotnih obdelav predstavlja izzive raziskovalnih in znanstvenih institucij, kar pomaga pri napredku tako metalurške stroke kot tudi industrijskih obratov. Kljub morebitnim spremembam morajo končni izdelki zagotavljati ustrezno mikrostrukturo in mehanske lastnosti. Namen magistrskega dela je bil analizirati vpliv toplotnih obdelav pred postopkom iztiskovanja in po njem na končne mehanske lastnosti iztiskovanih palic. Cilji so bili usmerjeni v analizo utrjevalno-izločevalne aluminijeve zlitine EN AW-2011, izvedbo različnih toplotnih obdelav, nateznih preizkusov in merjenje trdot. Hkrati so bili rezultati mehanskih preizkusov podkrepljeni z analizami svetlobne mikroskopije, vrstične elektronske mikroskopije ter diferenčne vrstične kalorimetrije. Raziskovalni problem je predstavljalo iskanje optimalne izvedbe homogenizacije (pred iztiskovanjem) in staranja (po iztiskovanju), pri čemer bi implementacija tovrstnih ugotovitev v industriji predstavljala tudi ekonomski vidik ter zmanjšala količino CO2 na kilogram proizvedenega aluminija. Raziskovalno delo je v začetku zajemalo pregled in analizo literaturnih virov. V ospredju so bile analize toplotnih obdelav za sorodne oz. podobne zlitine obravnavani EN AW-2011. Vzorčenju vertikalno polkontinuirno litih drogov je sledila sistematična izvedba toplotne obdelave (homogenizacije) pri temperaturi 520 °C in 8 različnih časih (laboratorijske žarilne peči). Izvedba analiz DSC je služila za ugotovitev in potrditev uspešnosti in ustreznosti omenjene toplotne obdelave. Na podlagi teh tez so se izbrali parametri homogenizacije za nadaljnjo raziskavo. Karakterizacija iztiskovanih palic je zagotovila sledenje celotnemu, tudi preoblikovalnemu delu eksperimentalnega procesa. Po vzoru sistematično izvedenih toplotnih obdelav homogenizacije je bila izvedena tudi toplotna obdelava umetnega staranja. Razpon omenjene toplotne obdelave je obsegal tri različne temperature in temu prilagojene časovne intervale. Obseg raziskav proizvodne verige je potrdil najoptimalnejše parametre homogenizacije 520 °C 4 ure in umetnega staranja pri 170 °C 14 ur.

• Language: Slovenian
• Keywords: aluminijeva zlitina EN AW-2011, toplotna obdelava, homogenizacija, umetno staranje, mehanske lastnosti
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Place of publishing: Ljubljana
• Publisher: [T. Smolar]
• Year: 2021
• Number of pages: XVI, 68 f.
• PID: 20.500.12556/RUL-131359
• UDC: 669
• COBISS.SI-ID: 84829443
• Publication date in RUL: 25.09.2021

SMOLAR, Tinkara, 2021, Vpliv toplotnih obdelav na mehanske lastnosti aluminijeve zlitine EN AW-2011 : magistrsko delo [online]. Master’s thesis. Ljubljana : T. Smolar. [Accessed 25 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=131359

Secondary language

• Language: English
• Title: Influence of heat treatments on mechanical properties of aluminium alloy EN AW-2011 : master's thesis

Abstract

Extrusion, as a metal forming process, represents a complete individual step in the entire metallurgical verification. In the case of heat-hardening alloys, heat treatment is also crucial in addition to deformation. Homogenization, which is carried out before the extrusion process, and aging, which is carried out after the extrusion process, are the key to the researcher in the industrial energy and economics. Optimizing more time and temperature favorable heat treatments presents challenges to research and scientific institutions, which helps in the progress of both metallurgical science and industrial plants. In addition to possible changes, the final products must provide suitable microstructure and mechanical properties. The purpose of the master's thesis was to analyze the influence of heat treatments before and after the extrusion process on the final mechanical properties of extruded bars. The objectives were focused on the analysis of the precipitation hardening aluminum alloy EN AW-2011, the implementation of various heat treatments, tensile tests and measured hardness. At the same time, the results of mechanical tests were supported by the analysis with light microscopes, scanning electron microscopy and differential scanning calorimetry. The research problem was the search for optimal implementation of homogenization (before extrusion) and aging (after extrusion), where the implementation of such findings in industry would also represent an economic aspect. The research work initially included a review and analysis of literature sources. At the forefront were the analyzes of heat treatments for related or similar alloys as EN AW-2011. Sampling of vertically semi-continuously cast bars was followed by systematic heat treatment (homogenization) at a temperature of 520 °C at 8 different times (laboratory annealing furnaces). Carrying out a DSC analysis, which was found to confirm the effectiveness and adequacy of the mentioned heat treatment. Based on these theses, the homogenization parameters were selected for further research. The characterization of the extruded bars ensured the tracking of the entire, including the deformation part of the experimental process. Following the example of systematically performed heat treatment of homogenization, heat treatment of artificial aging was also performed. The range of mentioned heat treatments included three different temperatures and time intervals adapted to them. The scope of research in the production chain confirmed the most optimal parameters of homogenization at 520 °C for 4 hours and artificial aging at 170 ° C for 14 hours.

• Keywords: Aluminum alloy EN AW-2011, heat treatment, homogenization, artificial aging, mechanical propertie