Vpliv specifične površine sekundarnega aluminija na kakovost zlitine AA7075

Okorn, Matija (author), Medved, Jože (mentor)

Aluminijeva zlitina AA7075 (AlZn6Mg2Cu1) je ena najpogosteje uporabljenih preoblikovalnih zlitin v industriji. Zaradi dobrega razmerja med trdnostjo in težo, ter zmožnostmi naravnega staranja je primerna za številne dele v letalski in avtomobilski industriji, ter druge izdelke kot je na primer plezalna oprema. Aluminijevo zlitino AA7075 smo izdelali iz primarnih in sekundarnih surovin, pri čemer smo še posebej upoštevali in analizirali specifično površino uporabljenega sekundarnega materiala. Namen diplomskega dela je bil ugotoviti kakšen vpliv ima specifična površina sekundarnega aluminija na kakovost zlitin AA7075. Za preiskavo izdelanih zlitin smo uporabili: enostavno termično analizo (ETA), diferenčno vrstično kalorimetrijo (DSC), rentgensko fluorescenčno analizo (XRF) in oceno specifične površine. S pomočjo XRF analize smo izmerili sestavo vsake uporabljene sekundarne surovine (z veliko in majhno specifično površino). Pri prvi šarži smo uporabili 100 % primarne zlitine, pri drugi in tretji pa približno 50 % primarne in 50 % sekundarne surovine z različno specifično površino. Na podlagi različnih sestav materiala smo natančno določili koliko legirnih elementov je potrebno dodati za izdelavo zlitine AA7075 v mejah standarda. Pri taljenju smo ugotovili, da se z vnosom sekundarnega materiala z večjo specifično površino povečuje delež žlindre. To se zgodi zaradi večje površine uporabljenega sekundarnega materiala na kateri je več nečistoč in vključkov. Ugotovili smo tudi, da se z dodajanjem sekundarnega materiala karakteristične točke ohlajevalnih krivulj višajo.

• Language: Slovenian
• Keywords: aluminijeva zlitina AA7075, reciklaža, sekundarni material, specifična površina
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2017
• PID: 20.500.12556/RUL-97657
• Publication date in RUL: 04.11.2017

Secondary language

• Language: English
• Title: Influence of specific surface of secondary aluminium on quality of AA7075 alloy

Abstract

Aluminum alloy AA7075 (AlZn6Mg2Cu1) is one of the most used alloys in the industry. Due to the well balanced strength, weight and natural aging capabilities, it is suitable for production of many parts used in aerospace, automotive industry and other products (climbing equipment). We made aluminum alloy AA7075 from primary and secondary raw materials, especially considering and determanig the specific surface of the used secondary material. The main purpose of the diploma work was to determine the influence of the specific surface of the secondary aluminum on the quality of the final AA7075 alloy. In our research : simple thermal analysis (ETA), differential calorimetry (DSC), X-ray fluorescence analysis (XRF) and approximation of specific surface were used. By using the XRF analysis we determined the composition of each secondary material (with large and small specific surface area). At the first batch 100% of the primary alloy was used, at the second and third batches approximately 50% of primary and 50% of secondary alloy having different specific surface. Based on the different material (alloy) composition we determined the how many alloying elements should be added for the production of the AA7075. Using the melting process we found out that the procentage of slag as a byproduct increases with the input of the secondary aluminum with a larger specific surface. This occures because of the fact that the larger specific surface brings more impurities to the melting proces. We found out, that the addition of the secondary material causes the rise of the characteristic points in cooling curves.

• Keywords: aluminum alloy AA7075, recycling, secondary material, specific surface