INFLUENCE OF CORROSION ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF 3XXX, 5XXX, AND 6XXX SERIES ALUMINUM ALLOYS

Abstract

Growing demands imposed on passenger car producers concerning the reduction of exhaust emission to the environment are forcing a search for new materials and design solutions. One of the most-important factors that can reduce this emission is the low mass of a vehicle, leading to a decrease in its average fuel consumption. A reduction in weight can be obtained by the use of aluminum elements instead of steel; e.g., in air conditioning pipes, decreasing the specific weight of the construction by nearly three times. In the present study, the influence of the SWAAT corrosion test on A/C piping made from 3xxx, 5xxx, and 6xxx series aluminum alloys was investigated. The study focused on changes in the mechanical properties of samples before and after a SWAAT test determined by a tensile test and Vickers hardness measurements. Additionally, microstructure examinations were performed with the use of optical and scanning microscopy. Corrosion products on the surface of pipes were identified by Energy Dispersive X-ray Spectroscopy. Pipes made from the EN AW 6063 alloy revealed an almost 50% decrease in its strength properties after the tests. The largest decline in plastic properties was observed in pipes made from the EN AW 6060 alloy.