Vroče preoblikovanje zlitine EN AW 3003

Godec, Domen (author), Fajfar, Peter (mentor)

V diplomskem delu smo se ukvarjali z vročim preoblikovanjem aluminijeve zlitine EN AW 3003. Valjaste tlačne preizkuse smo izvedli na simulatorju termomehanskih stanj Gleeble 1500D. Pri temperaturah 300 °C, 400°C in 500 °C smo izvedli teste pri hitrostih deformacije 0,1 s-1, 1 s-1, 10 s¬-1. Iz rezultatov tlačnih preizkusov smo v programu Origin izdelali krivulje tečenja, iz katerih smo razbrali, da se maksimumi napetosti pojavijo kasneje pri nižjih temperaturah in prej pri višjih temperaturah. Iz maksimumov napetosti smo izračunali navidezno aktivacijsko energijo za vroče preoblikovanje preiskovane aluminijeve zlitine, katera znaša 195,07 kJ∙mol-1. S pomočjo parametrov Sellarsove enačbe smo maksimume napetosti še izračunali. Dobljene vrednosti se zelo dobro ujemajo z izmerjenimi. Krivulje tečenja smo odvajali, da smo dobili diagram hitrosti utrjevanja v odvisnosti od prave napetosti. Na osnovi analize diagramov hitrosti utrjevanja s »Poliak-Jonas« kriterijem, smo lahko določili kritične napetosti za začetek dinamične rekristalizacje. Ugotovili smo, da se proces dinamične rekristalizacije prične hitreje pri višjih temperaturah in nizkih hitrostih deformacije kot pri nižjih temperaturah in visokih hitrostih deformacije. Vzorce smo po izvedenih preizkusih prerezali in pripravili za metalografsko analizo. Ta je bila izvedena z uporabo optičnega mikroskopa pri 25-kratni in 100-kratni povečavi. Iz mikrostruktur smo ugotovili, da pri nekaterih vzorcih ne poteče dinamična rekristalizacija, vendar pa statična rekristalzacija.

• Language: Slovenian
• Keywords: Aluminijeva zlitina, tlačni preizkus, vpliv hitrosti deformacije, krivulje tečenja, dinamična rekristalizacija.
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2018
• PID: 20.500.12556/RUL-104033
• COBISS.SI-ID: 1772639
• Publication date in RUL: 03.10.2018

GODEC, Domen, 2018, Vroče preoblikovanje zlitine EN AW 3003 [online]. Bachelor’s thesis. [Accessed 2 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=104033

Secondary language

• Language: English
• Title: Hot workability of EN AW 3003 alloy

Abstract

In the diploma work we dealt with hot workability of the aluminium alloy EN AW 3003. Cylindrical pressure tests were performed on the Gleeble 1500D thermo-mechanical state simulator. We performed tests at the temperatures 300 °C, 400 °C and 500 °C at the deformation rates of 0.1 s-1, 1 s-1, 10 s-1. We edited the data from pressure tests in program Origin, where we produced flow curves, from which we found, that the maximums stresses occur later at lower temperatures and earlier at higher temperatures. The apparent activation energy for the hot deformation of the investigated aluminium alloy was calculated from the maximum stresses and it yields 195,07 kJ ∙ mol-1. Using the parameters of the Sellars equation, we have calculated the maximum stresses. The values obtained, closely match the measured values. The flow curves were derivated to obtain a diagram of hardening speed as a function of true stress. Based on the analysis of the hardening speed diagrams with the "Poliak-Jonas" criterion, we could determine the critical stresses for the beginning of dynamic recrystallization. We found that the process of dynamic recrystallization begins faster at higher temperatures and low deformation rates than at lower temperatures and high deformation rates. After the experiments, the samples were cut in half and prepared for metallographic analysis. This was done using an optical microscope at 25x and 100x magnification. After analysis of microstructures, we found that in some samples static recrystallization occurs instead of dynamic recrystallization.

• Keywords: Aluminium alloy, pressure test, impact of deformation rate, flow curves, dynamic recrystallization.