Unravelling the effect of temperature and humidity alternation on 6061 aluminium alloy corrosion behaviour in simulated urban industrial environment

Abstract

The effect of temperature and humidity alternation on the corrosion behaviour and mechanical properties of 6061 aluminium alloy in a simulated urban industrial atmospheric environment was investigated and analysed by weightlessness method, scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Fourier infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and dynamic potential polarization (LSV). The fluctuation of the composition, structure, and morphology of the corrosion product layer is studied; the entry of corrosive medium destroys the densification; and the second phase brings the potential difference, which causes the corrosion to expand internally and accelerates the localized corrosion. The corrosion rate shows a trend of first gradually increasing and then decreasing, corresponding to the formation of the initial oxide film hinders the corrosion, and then the local product film separation leads to the weakening of the corrosion resistance. The mechanical properties are significantly reduced after corrosion, and the fracture mechanism is transformed from the ductile fracture to the cleavage fracture gradually. This study also provided some theoretical guidance for the accelerated simulation tests of Al alloys in the marine atmosphere.