Corrosion Behavior and Microstructure of Er Containing 5083 and 5A06 Al-Mg Alloys

The corrosion behavior of hot rolled and annealed(at 350 ℃ for 1 h)Al-Mg alloys 5083 and 5A06 micro-alloyed with small amount of Er was investigated by means of immersion tests and electrochemical dynamic potential cycle polarization measurements. For the untreated samples and those after immersion tests, the morphology and microstructure were examined by optical microscopy (OM), scan electron microscopy (SEM), transmission electron microscopy (TEM) together with energy dispersion spectrum (EDS). The results showed that both 5083 and 5A06 with trace Er addition were of good corrosion resistance, and the corresponding corrosion rates were in the range of μA/cm2 when measured in 3.5% NaCl solution. The trace Er addition didn't worsen the corrosion-resistance. The high content of some major alloying element Mg affected greatly the corrosion behavior, and the heat treatment parameters had some effect as well.