Effect of Solution Temperature on the Corrosion Behavior of 6061-T6 Aluminum Alloy in NaCl Solution

The influence of solution temperature on the corrosion behavior of 6061-T6 aluminum alloy in 3.5% NaCl solution was studied by electrochemical tests, weight loss method, and surface morphology analysis. The results show that the samples treated at different solution temperatures have different corrosion resistance. The anticorrosion resistance of aluminum alloys decreases first and then increases as the solution temperature increases. At 535 °C, the sample has the optimal corrosion resistance, with a slight corrosion degree, while the alloy sample treated at 555 °C shows the most severe degree of corrosion, with a large number of different sized pits and some ulcerous corrosion pits, as well the apparent intergranular corrosion. The corrosion behavior of different solid aluminum alloy samples is closely related to the microstructure. The Mg2Si precipitates act as the anode phase to protect the substrate, and a decrease in the amount of AlFeSi precipitates reduces the number of micro-galvanic corrosion cells, and the severe segregation of AlFeSi precipitates accelerates the corrosion.