Termodinamična karakterizacija zlitin EN AW 6028 in EN AW 6262 v litem in homogeniziranem stanju

Lunežnik, Žiga (author), Medved, Jožef (mentor), Steinacher, Matej (comentor)

Aluminijevi zlitini EN AW 6028 in EN AW 6262 (Al-Mg-Si) spadata med tiste z dobro kombinacijo trdnosti, obdelovalnosti in odpornosti proti koroziji. Kemijska sestava – Al: 90–98 mas. %, Mg: 0,6–1,5 mas. %, Si: 0,4–1,5 mas. %, Cu: 0,1–0,6 mas.%, Fe: do 0,7 mas. % – omogo a toplotno obdelavo in s tem izboljbanje mehanskih lastnosti. Najve se uporabljata v gradbenibtvu, avtomobilski industriji, letalski industriji in za izdelavo strojnih komponent. Namen diplomskega dela je izvedba termodinami ne karakterizacije zlitin EN AW 6028 in EN AW 6262. S programom Thermo-Calc smo izvedli termodinami ne izra une ravnote~nega in neravnote~nega stanja in na podlagi dobljenih izra unov izrisali fazne diagrame ter Scheil-ove diagrame. Izvedli smo tudi diferen no vrsti no kalorimetrijo (DSC) za vzorca v litem in homogeniziranem stanju s pomo jo naprave NEZTSCH DSC 404 F3 Pegasus. Od itali smo karakteristi ne temperature in odgovarjajo e entalpije tvorbe posameznih faz. Termodinami ni izra uni za zlitini EN AW 6028 in EN AW 6262 ka~ejo, da se pri strjevanju najprej tvorijo primarni zmesni kristali ?-Al, nato pa evtektiki s fazami Mg3Bi2, Al15Si2Mn4 in Mg2Si. Mikrostruktura prikazuje primarna dendritna zrna zmesnih kristalov ?-Al, po kristalnih mejah pa evtektike. Po homogenizaciji ni ve opaziti Mg2Si faze, pojavi pa se pove ana poroznost. Strjevanje poteka med 700 in 470 °C.

• Language: Slovenian
• Keywords: aluminijeve zlitine, EN AW 6028, EN AW 6262, termodinami ni izra uni, diferen na vrsti na kalorimetrija
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2024
• PID: 20.500.12556/RUL-162026
• Publication date in RUL: 18.09.2024

Secondary language

• Language: English
• Title: Thermodynamic characterization of EN AW 6028 and EN AW 6262 alloys in cast and homogenized state

Abstract

Aluminium alloys EN AW 6028 and EN AW 6262 (Al-Mg-Si) are among those with a good combination of strength, machinability and corrosion resistance. The chemical composition - Al: 90–98% by weight, Mg: 0.6–1.5% by weight, Si: 0.4–1.5% by weight, Cu: 0.1–0.6% by weight, Fe: up to 0.7% by weight - allows heat treatment and thus an improvement of the mechanical properties. They are mainly used in the construction, automotive, aerospace and machine component industries. The aim of the thesis is to carry out a thermodynamic characterisation of EN AW 6028 and EN AW 6262 alloys. Thermodynamic calculations of the equilibrium and nonequilibrium states have been carried out with the Thermo-Calc program and phase diagrams and Scheil diagrams have been drawn on the basis of the obtained calculations. Differential scanning calorimetry (DSC) was also performed for the cast and homogenised samples using a NEZTSCH DSC 404 F3 Pegasus. The characteristic temperatures and the corresponding enthalpies of formation of the individual phases were read. Thermodynamic calculations for EN AW 6028 and EN AW 6262 alloys show that at the solidification, primary α-Al mixture crystals form first, followed by eutectics with Mg3Bi2, Al15Si2Mn4 and Mg2Si phases. The microstructure shows the primary dendritic grains of the primary α-Al mixture crystals and the eutectics along the crystal boundaries. After homogenisation, the Mg2Si phase is no longer observed, but increased porosity appears. Solidification takes place between 700 and 470 °C.

• Keywords: aluminium alloys, EN AW 6028, EN AW 6262, thermodynamic calculations, differential scanning calorimetry