Comparation of corrosion and mechanical properties of commercial and recycled 6060 and 6082 aluminium alloys

Abstract

Although the same quality of various metals from the recycling process is considered for granted, obtaining aluminum of high purity and aluminum alloys with identical properties as from production from pure raw materials is a very challenging process, especially if the sources for recycling are numerous materials that contain different impurities. In this study, recycled alloys were produced by melting of aluminum scrap with the addition of the required components. This paper aims to compare two commercial Al alloys with their analogs from the recycling process. Both of the alloys belong to the aluminum series 6000, with designations 6060 and 6082. The results of comparing corrosion and physical characteristics are presented in this study. Physical characterization was performed by measuring the alloys' hardness and electrical conductivity. The electrochemical investigation used several corrosion methods, OCP (open circuit potential), measuring polarization curves in apparent Tafel region with extrapolation of results, and LRP (linear polarization resistance). The corrosion environment was acidulated 0.5M Na2SO4 with pH=2.5. The received results have confirmed insignificant differences between the properties of the commercial and alloys produced by the recycling. Recycled alloys have achieved almost identical mechanical properties and even slightly better corrosion characteristics, which was the consequence of the lower concentration of impurities in recycled alloys or higher concentration of microalloying components.