Effect of rolling temperature on the corrosion resistance of AZ61 magnesium alloy

The microstructure and properties of AZ61 magnesium alloy after rolling (rolling temperature: 300, 350, 380 and 400 ℃) were characterized and tested by metallographic microscopy, X-ray diffraction, polarization curves, electrochemical impedance spectroscopy and immersion tests, respectively. The influence of the rolling temperature on the microstructure of AZ61 magnesium alloy and the genetic effect of the temperature on the corrosion resistance were studied, and the mapping relationship between its rolling temperature and corrosion resistance was clarified, respectively. The results showed that with increasing rolling temperature, the grain size of the AZ61 magnesium alloy first decreased and then increased, the content of the β phase decreased first, then increased, and then decreased, and its corrosion resistance increased first, then decreased, and then increased. The corrosion behavior of the AZ61 magnesium alloy was first localized pitting corrosion and then extended to surface corrosion. When the rolling temperature was 350 ℃, the grain size of the alloy was the smallest, the content of the β phase was the lowest, and the alloy had the best corrosion resistance at this time. The polarization resistance was as high as 530.970 Ω·cm², the corrosion potential was -1.470 V, the corrosion current density was 8.415×10^-6 A/cm², and the average corrosion rate was as low as 1.14×10^-4 g/(cm²·h).