Optimiranje udrobnjevanja aluminijeve zlitine EN AW-6110A

Dabanović, Jaka (author), Medved, Jožef (mentor)

V diplomskem delu smo določevali najprimernejšo količino udrobnjevalca v obliki predzlitine AlTi3B1 in najustreznejši kontaktni čas udrobnjevalca s talino za aluminijevo zlitino EN AW-6110A, ki vsebuje silicij in magnezij kot glavna legirna elementa. Cilj je bil doseči velikost kristalnih zrn α-Al pod 180 µm. Eksperimentalni del je potekal v dveh serijah. V prvi smo ulili osem vzorcev. Dva sta bila primerjalna, ostalim smo dodajali različne količine predzlitine. Izkazalo se je, da je najprimernejši dodatek 0,02 mas.% Ti, ki nam je dal povprečno velikost kristalnih zrn 212,6 µm. V drugi seriji smo nato ulili osem vzorcev s količino dodanega titana 0,02 mas.% Ti pri različnih kontaktnih časih s talino. Najmanjša kristalna zrna smo dobili pri času 2 min s povprečno velikostjo kristalnih zrn 157,5 µm. Na vseh vzorcih smo med litjem in procesom strjevanja izvajali enostavno termično analizo, s katero smo določili likvidus temperaturo, temperature strjevanja evtektikov in solidus temperaturo. Izvedli smo tudi termodinamični izračun za izris izopletnih faznih diagramov, diagramov lastnosti in Scheilovih diagramov. S pomočjo teh smo določili faze, ki so nastopale v naši zlitini. Vzorce smo opazovali pod svetlobnim mikroskopom in skladno s standardom ASTM E 112-96 določili velikost kristalnih zrn. Na koncu eksperimentalnega delaš smo še za vse vzorce izvedli diferenčno vrstično kalorimetrijo, pri kateri smo s pomočjo segrevalnih in ohlajevalnih krivulj dobili karakteristične temperature in talilne ter strjevalne entalpije. Za ovrednotenje rezultatov smo izrisali grafe za primerjavo velikosti kristalnih zrn in likvidus temperatur.

• Language: Slovenian
• Keywords: Ključne besede: Zlitine EN AW-6110A, udrobnjevanje, velikost kristalnih zrn, enostavna termična analiza, diferenčna vrstična kalorimetrija
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2018
• PID: 20.500.12556/RUL-101941
• COBISS.SI-ID: 1739359
• Publication date in RUL: 14.07.2018

DABANOVIĆ, Jaka, 2018, Optimiranje udrobnjevanja aluminijeve zlitine EN AW-6110A [online]. Bachelor’s thesis. [Accessed 18 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=101941

Secondary language

• Language: English
• Title: Optimization of grain refinement of alloy EN AW-6110A

Abstract

In this BSc thesis, we determined the most appropriate quantity of grain refiner in the form of the AlTi3B1 master alloy and the most appropriate grain refiner and melt contact time to form the EN AW-6110A aluminium alloy containing silicon and magnesium as the main alloying elements. The aim was to achieve the grain size of α-Al crystals of below 180 µm. The experimental portion was performed in two series. In the first series, we cast eight samples. Two were comparative samples, while we added different quantities of the master alloy to the other samples. It turned out that the most suitable surcharge is 0.02 weight percent of titanium in the total alloy which yielded the average crystal grain size of 212.6 µm. In the second series, we cast eight samples with 0.02 weight percent of titanium added at different contact times with the melt. The smallest crystal grains were obtained at the contact time of 2 minutes with the average crystal grain size of 157.5 µm. We performed a simple thermal analysis on all samples during the casting and solidification in order to determine the start of the liquidus temperature, the solidification temperature of eutectic mixtures and the solidus temperature. We performed the thermodynamic calculation to produce isopleth maps, characteristic diagrams and Scheil diagrams. Using the above, we determine the phases occurring in our alloy. We observed the samples under the light microscope and determined crystal grain sizes according to the ASTM E 112-96 standard. At the end of the experimental portion, we performed differential scanning calorimetry on all samples whereby we used heating and cooling curves to obtain charasterictic temperatures and solidification and melting enthalpies. In order to evaluate the results, we produced charts to compare the crystal grain sizes and liquidus temperatures.

• Keywords: Keywords: alloy EN AW 6110A, grain refining, grain size, simple thermal analysis, differential scaning calorimetry