Vpliv specifične površine in deleža sekundarnega aluminija na kakovost zlitine AlSi10Mg(Fe) : magistrsko delo

Rudolf, Karlo (author), Vončina, Maja (mentor)

Aluminij je ena od barvnih lahkih kovin. Zaradi dobrih mehanskih lastnosti je druga najbolj uporabljena kovina. Aluminijevo livarska zlitina AlSi10Mg je pogosto uporabljena v avtomobilski industriji, predvsem zaradi ohranjanja dobrih mehanskih lastnosti pri povišanih obratovalnih temperaturah. V livarstvu se jo uliva najpogosteje po postopku tlačnega litja. Zaradi okoljevarstvenega vidika se vse bolj v proces izdelave surovin uveljavlja reciklaža sekundarnega aluminija. Za izdelavo reciklirane aluminijeve zlitine uporabljamo novi ter stari odpad, ki se zelo razlikuje med seboj po kemijski sestavi, vsebnosti nečistoč ter specifični površini. Na lastnosti zlitine vpliva delež krožne litine materiala, ki ga dodamo talini. Kako vse to vpliva na strjevanje, mehanske lastnosti ter na razvoj mikrostrukture smo raziskovali v magistrski nalogi. Raziskovali smo vpliv specifične površine ter delež krožne litine na strjevanje, razvoj mikrostrukturo ter mehanske lastnosti zlitine AlSi10Mg(Fe). Analize so potekale v litem stanju. Izdelali smo sedem vzorcev iz različnih deležev blokov ter krožne litine z različno specifično površino. Vpliv teh dveh spremenljivk na kakovost taline smo spremljali z analizami. Potek strjevanja smo analizirali z enostavno termično analizo ter diferenčno vrstično kalorimetrijo. Vpliv na mikrostrukturo smo analizirali s pomočjo optične mikroskopije ter izračunov Thermo-Calc. Vpliv specifične površine in delež krožne litine na mehanske lastnosti pa z meritvami trdote ter nateznim preizkusom, pri čemer smo spremljali natezno trdnost, mejo plastičnosti in raztezek. Večja kot je specifična površina ter delež surovin iz krožne litine uporabljene za izdelavo zlitine, slabše so mehanske lastnost. Vzroki za to so odgor nekaterih elementov, povečanje vnosa nečistoč ter povečanje deleža železa v zlitini.

• Language: Slovenian
• Keywords: zlitina AlSi10Mg(Fe), reciklaža, termodinamika, mehanske lastnosti, mikrostruktura, strjevanje
• 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: [K. Rudolf]
• Year: 2021
• Number of pages: XVI, 64 f.
• PID: 20.500.12556/RUL-134062
• UDC: 669
• COBISS.SI-ID: 92251907
• Publication date in RUL: 23.12.2021

Secondary language

• Language: English
• Title: Influence of specific surface and amount of recycling aluminium on AlSi10Mg(Fe) alloy quality : master's thesis

Abstract

Aluminium is one of the non-ferrous light metals. Due to its good mechanical properties, it is the second most used metal. Aluminium casting alloy AlSi10Mg is widely used in the automotive industry, mainly due to maintaining good mechanical properties at elevated operating temperatures. In foundry, it is most often casted by the process of die casting. Due to the environmental aspect, the recycling of secondary aluminium is gaining ground in the process of raw material production. To produce recycled aluminium alloy, we use new and old waste, which differs greatly in chemical composition, impurity content and specific surface. The properties of the alloy are affected by the proportion of secondary material added to the melt. How all this affects solidification, mechanical properties and the development of microstructure was investigated in the master 's thesis. We investigated the influence of specific surface area and the proportion of secondary material on solidification, development of microstructure and mechanical properties of AlSi10Mg(Fe) alloy. Analyses were performed in the cast state. We produced seven samples from different proportions of primary and secondary material with different specific surface area. The influence of these two variables on melt quality was monitored by several analyses. The solidification process was analyzed by simple thermal analysis and differential scanning calorimetry. The effect on the microstructure was determined using optical microscopy and Thermo-Calc calculations. Influence of specific surface and share of secondary material on mechanical properties were analyzed with hardness measurements and tensile test, where tensile strength, plastic limit and elongation were monitored. The larger the specific surface area and the proportion of secondary raw materials were used to make the alloy, the lower were the mechanical properties. The reasons for this are, the burning of some elements, an increase in the input of impurities and an increase in the proportion of iron in the alloy.

• Keywords: AlSi10Mg(Fe) alloy, recycling, thermodynamics, mechanical properties, microstructure, solidification